- Towards practical baeyer-villiger-monooxygenases: Design of cyclohexanone monooxygenase mutants with enhanced oxidative stability
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Baeyer-Villiger monooxygenases (BVMOs) catalyze the conversion of ketones and cyclic ketones into esters and lactones, respectively. Cyclohexanone monooxygenase (CHMO) from Acinetobacter sp. NCIMB 9871 is known to show an impressive substrate scope as wel
- Opperman, Diederik J.,Reetz, Manfred T.
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- Kinetic resolution of racemic 2-substituted 3-cyclopenten-1-ols by lipase-catalyzed transesterifications: A rational strategy to improve enantioselectivity
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The effect of the acyl group of acylating agents on the enantioselectivity in the Pseudomonas cepacia lipase-catalyzed acylations of racemic alcohols has been studied. 2-[(N,N-Dimethylcarbamoyl)-methyl]-3-cyclopenten-1-ol (1) and 2-[2-(tert-butyldimethylsilyloxy)ethyl]-3-cyclopenten-1-ol (4) were resolved with a variety of enantioselectivities. In the case of alcohol 1, the enantiomeric ratio (the E value) was increased by changing the acylating agent from vinyl acetate (E = 30) to vinyl butyrate (E = 156) and dropped substantially with longer acyl donors. With vinyl chloroacetate, the reaction rate was fast and the enantioselectivity was high (E = 89), whereas the resolution with vinyl trifluoroacetate resulted in a very poor enantioselectivity (E = 4). The bulky acylating agent, vinyl pivalate, gave a moderate enantioselectivity (E = 15). In the case of alcohol 4, the enantioselectivities were excellent (E > 142) except vinyl pivalate (E = 12). It is indicated that the acyl group transiently attached at the active site of the lipase acts as a stereochemical controller. The solvent effect is also described briefly. A clear correlation was observed between the E values and the log P values of the organic solvents; the smaller the log P value of the solvent, the higher the E value.
- Ema, Tadashi,Maeno, Soichi,Takaya, Yusuke,Sakai, Takashi,Utaka, Masanori
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- Lewis acidic Sn(IV) centers - Grafted onto MCM-41 - As catalytic sites for the Baeyer-Villiger oxidation with hydrogen peroxide
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Sn(IV) centers have been grafted onto mesoporous MCM-41 using different RnSnX4-n precursors. For a successful incorporation of the tin, one or two alkyl substituents are beneficial. The calcined samples are able to activate a carbonyl bond for nucleophilic attack as it could be shown by in situ IR spectroscopy. The resulting catalysts are active for the Baeyer-Villiger oxidation of various substrates with hydrogen peroxide and achieve good conversions and selectivities. Chemoselective oxidations toward unsaturated lactones are obtained from unsaturated ketones. The Lewis acidity and the catalytic performance of the grafted Sn(IV) centers are very similar to the directly synthesized Sn-MCM-41, but lower than those of the Sn-Beta zeolite.
- Corma, Avelino,Navarro, Maria Teresa,Renz, Michael
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- Aerobic Baeyer–Villiger Oxidation Catalyzed by a Flavin-Containing Enzyme Mimic in Water
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Direct incorporation of molecular oxygen into small organic molecules has attracted much attention for the development of new environmentally friendly oxidation processes. In line with this approach, bioinspired systems mimicking enzyme activities are of particular interest since they may perform catalysis in aqueous media. Demonstrated herein is the incorporation of a natural flavin cofactor (FMN) into the specific microenvironment of a water-soluble polymer which allows the efficient reduction of the FMN by NADH in aqueous solution. Once reduced, this artificial flavoenzyme can then activate molecular dioxygen under aerobic conditions and result in the Baeyer–Villiger reaction at room temperature in water.
- Chevalier, Yoan,Lock Toy Ki, Yvette,le Nouen, Didier,Mahy, Jean-Pierre,Goddard, Jean-Philippe,Avenier, Frédéric
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- Preparation method corey lactone diol
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The invention provides a preparation method of corey lactone diol, which has the advantages of easily available raw materials. The method has the characteristics of mild reaction conditions, simple operation, simple synthetic route, high chemical yield, low cost and the like, and is suitable for industrial production.
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- Divorce in the two-component BVMO family: The single oxygenase for enantioselective chemo-enzymatic Baeyer-Villiger oxidations
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Two-component flavoprotein monooxygenases consist of a reductase and an oxygenase enzyme. The proof of functionality of the latter without its counterpart as well as the mechanism of flavin transfer remains unanswered beyond doubt. To tackle this question, we utilized a reductase-free reaction system applying purified 2,5-diketocamphane-monooxygenase I (2,5-DKCMO), a FMN-dependent type II Baeyer-Villiger monooxygenase, and synthetic nicotinamide analogues (NCBs) as dihydropyridine derivatives for FMN reduction. This system demonstrated the stand-alone quality of the oxygenase, as well as the mechanism of FMNH2transport by free diffusion. The efficiency of this reductase-free system strongly relies on the balance of FMN reduction and enzymatic (re)oxidation, since reduced FMN in solution causes undesired side reactions, such as hydrogen peroxide formation. Design of experiments allowed us to (i) investigate the effect of various reaction parameters, underlining the importance to balance the FMN/FMNH2cycle, (ii) optimize the reaction system for the enzymatic Baeyer-Villiger oxidation of rac-bicyclo[3.2.0]hept-2-en-6-one,rac-camphor, andrac-norcamphor. Finally, this study not only demonstrates the reductase-independence of 2,5-DKCMO, but also revisits the terminology of two-component flavoprotein monooxygenases for this specific case.
- R?llig, Robert,Paul, Caroline E.,Claeys-Bruno, Magalie,Duquesne, Katia,Kara, Selin,Alphand, Véronique
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supporting information
p. 3441 - 3450
(2021/05/03)
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- Genome Mining of Oxidation Modules in trans-Acyltransferase Polyketide Synthases Reveals a Culturable Source for Lobatamides
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Bacterial trans-acyltransferase polyketide synthases (trans-AT PKSs) are multimodular megaenzymes that biosynthesize many bioactive natural products. They contain a remarkable range of domains and module types that introduce different substituents into growing polyketide chains. As one such modification, we recently reported Baeyer–Villiger-type oxygen insertion into nascent polyketide backbones, thereby generating malonyl thioester intermediates. In this work, genome mining focusing on architecturally diverse oxidation modules in trans-AT PKSs led us to the culturable plant symbiont Gynuella sunshinyii, which harbors two distinct modules in one orphan PKS. The PKS product was revealed to be lobatamide A, a potent cytotoxin previously only known from a marine tunicate. Biochemical studies show that one module generates glycolyl thioester intermediates, while the other is proposed to be involved in oxime formation. The data suggest varied roles of oxygenation modules in the biosynthesis of polyketide scaffolds and support the importance of trans-AT PKSs in the specialized metabolism of symbiotic bacteria.
- Ueoka, Reiko,Meoded, Roy A.,Gran-Scheuch, Alejandro,Bhushan, Agneya,Fraaije, Marco W.,Piel, J?rn
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supporting information
p. 7761 - 7765
(2020/03/25)
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- Genome mining reveals new bacterial type I Baeyer-Villiger monooxygenases with (bio)synthetic potential
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Baeyer-Villiger monooxygenases (BVMOs) are oxidorreductases that catalyze the oxidation of ketones in a very selective manner. By genome mining we detected seven putative type I BVMOs in Bradyrhizobium diazoefficiens USDA 110. As we established the phylogenetic relationships among them and with other type I BVMOs, we found out that they belong to different clades of the phylogenetic tree. Thus, we decided to clone and heterologously express five of them. Three of them, each one from a divergent phylogenetic group, were obtained as soluble proteins, allowing us to proceed with their biocatalytic assessment and enzymatic characterization. As to substrate scope and selectivity, we observed a complementary behavior among the three BVMOs. BVMO2 was the more versatile biocatalyst in whole-cell systems while BVMO4 and BVMO5 showed a narrow substrate profile with preference for linear ketones and particular regioselectivity for (±)-cis-bicyclo[3.2.0]hept-2-en-6-one.
- Bianchi, Dario A.,Carabajal, María Ayelén,Ceccoli, Romina D.,Rial, Daniela V.
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- A synthesis method of the branch stands lactone diol
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The invention discloses a method for the branch stands lactone diol (( -) - Corey lactone diol) synthetic method, synthesis method of the invention is to dicyclopentadiene as raw materials, by depolymerization, cyclization, oxidation, dechlorination, open-loop, split, Prins reaction, hydrolysis reaction to obtain the target product. The invention discloses a synthetic route, raw material economic, high separation efficiency, and is suitable for industrial production.
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- Flavinium and Alkali-Metal Assembly on Sulfated Chitin: A Heterogeneous Supramolecular Catalyst for H2O2-Mediated Oxidation
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Heterogeneous multiple-catalyst assemblies were developed in which the flavinium cation and Na or Li cations were easily immobilized on a chitin-derived anionic polymeric scaffold through noncovalent ionic interactions. The supramolecular flavinium catalysts were successfully employed in the environmentally friendly heterogeneous Baeyer–Villiger oxidation and sulfoxidation by H2O2. Owing to the cooperative catalytic effect of flavinium, alkali metal, and sulfated chitin, the supramolecular flavinium assembly showed higher catalytic activity for the Baeyer–Villiger oxidation of cyclic ketones than the corresponding homogeneous flavinium catalyst. Because the ionic assembly was stable under the reaction conditions, the catalyst could be readily recovered by simple filtration and reused.
- Sakai, Takuya,Watanabe, Mirai,Ohkado, Ryoma,Arakawa, Yukihiro,Imada, Yasushi,Iida, Hiroki
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p. 1640 - 1645
(2019/03/26)
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- A simple and efficient synthesis of the Corey lactone diol (by machine translation)
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The present invention provides a simple and efficient synthesis of the Corey lactone glycol method, comprises the following steps: step one, the cyclopentadiene in the organic solvent is added, and adding a Lewis acid as a catalyst, at the same time [...] and acetyl chloride to the cyclization reaction, after reaction quenching, extraction, washing, filtration, concentration, compound I prepared; step two, the compound I in the solvent addition of an oxidizing agent to carry out oxidation reaction, generating compounds II; step three, the compound II under basic condition, acidifying the resulting open-loop compound, adding a chiral split reaction of the phenethylamine, then cyclized to obtain compound III; step four, the paraformaldehyde dissolved in the sulfuric acid solution, then dripping into compound III, under pressure, through the Prins addition, Corey lactone diol obtained. The invention discloses a simple and efficient synthesis of the Corey lactone diol, raw materials are apt, the step is short, simple operation, high yield, high optical purity of the obtained product, and is suitable for industrial production and the like. (by machine translation)
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- Comparison of riboflavin-derived flavinium salts applied to catalytic H2O2 oxidations
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A series of flavinium salts, 5-ethylisoalloxazinium, 5-ethylalloxazinium, and 1,10-ethylene-bridged alloxazinium triflates, were prepared from commercially available riboflavin. This study presents a comparison between their optical and redox properties, and their catalytic activity in H2O2 oxidations of sulfide, tertiary amine, and cyclobutanone. Reflecting the difference between the π-conjugated ring structures, the flavinium salts displayed very different redox properties, with reduction potentials in the order of: 5-ethylisoalloxazinium > 5-ethylalloxazinium > 1,10-ethylene-bridged alloxazinium. A comparison of their catalytic activity revealed that 5-ethylisoalloxazinium triflate specifically oxidises sulfide and cyclobutanone, and 5-ethylalloxazinium triflate smoothly oxidises tertiary amine. 1,10-Bridged alloxazinium triflate, which can be readily obtained from riboflavin in large quantities, showed moderate catalytic activity for the H2O2 oxidation of sulfide and cyclobutanone.
- Sakai, Takuya,Kumoi, Takuma,Ishikawa, Tatsuro,Nitta, Takahiro,Iida, Hiroki
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supporting information
p. 3999 - 4007
(2018/06/08)
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- Controlling the Regioselectivity of Baeyer–Villiger Monooxygenases by Mutation of Active-Site Residues
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Baeyer–Villiger monooxygenase (BVMO)-mediated regiodivergent conversions of asymmetric ketones can lead to the formation of “normal” or “abnormal” lactones. In a previous study, we were able to change the regioselectivity of a BVMO by mutation of the active-site residues to smaller amino acids, which thus created more space. In this study, we demonstrate that this method can also be used for other BVMO/substrate combinations. We investigated the regioselectivity of 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-CoA monooxygenase from Pseudomonas putida (OTEMO) for cis-bicyclo[3.2.0]hept-2-en-6-one (1) and trans-dihydrocarvone (2), and we were able to switch the regioselectivity of this enzyme for one of the substrate enantiomers. The OTEMO wild-type enzyme converted (?)-1 into an equal (50:50) mixture of the normal and abnormal products. The F255A/F443V variant produced 90 % of the normal product, whereas the W501V variant formed up to 98 % of the abnormal product. OTEMO F255A exclusively produced the normal lactone from (+)-2, whereas the wild-type enzyme was selective for the production of the abnormal product. The positions of these amino acids were equivalent to those mutated in the cyclohexanone monooxygenases from Arthrobacter sp. and Acinetobacter sp. (CHMOArthro and CHMOAcineto) to switch their regioselectivity towards (+)-2, which suggests that there are hot spots in the active site of BVMOs that can be targeted with the aim to change the regioselectivity.
- Balke, Kathleen,B?umgen, Marcus,Bornscheuer, Uwe T.
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p. 1627 - 1638
(2017/08/26)
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- Anion effect of 5-ethylisoalloxazinium salts on flavin-catalyzed oxidations with H2O2
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The anion effect of the 5-ethylisoalloxazinium salts on their catalytic activity was investigated for the oxidation of sulfide with aq H2O2in order to design more practical and safer flavinium salt catalysts that can replace the conventional perchlorate salt. The anions forming stronger conjugated acids were found to accelerate the catalytic sulfoxidation. The riboflavin-derived isoalloxazinium triflate salt was chosen as a readily accessible flavin with an efficient catalytic activity. In fact, the isoalloxazinium triflate 1b is an excellent organocatalyst for the chemoselective oxidations of a sulfide to a sulfoxide, Bayer–Villiger reaction of a cyclobutanone to a γ-butyrolactone, Dakin reaction of an arylaldehyde to a phenol, and oxidation of an aldehyde to a carboxylic acid using aq H2O2as a terminal oxidant under mild conditions.
- Iida, Hiroki,Ishikawa, Tatsuro,Nomura, Keisuke,Murahashi, Shun-Ichi
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supporting information
p. 4488 - 4491
(2016/09/14)
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- Characterization and Crystal Structure of a Robust Cyclohexanone Monooxygenase
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Cyclohexanone monooxygenase (CHMO) is a promising biocatalyst for industrial reactions owing to its broad substrate spectrum and excellent regio-, chemo-, and enantioselectivity. However, the low stability of many Baeyer–Villiger monooxygenases is an obstacle for their exploitation in industry. Characterization and crystal structure determination of a robust CHMO from Thermocrispum municipale is reported. The enzyme efficiently converts a variety of aliphatic, aromatic, and cyclic ketones, as well as prochiral sulfides. A compact substrate-binding cavity explains its preference for small rather than bulky substrates. Small-scale conversions with either purified enzyme or whole cells demonstrated the remarkable properties of this newly discovered CHMO. The exceptional solvent tolerance and thermostability make the enzyme very attractive for biotechnology.
- Romero, Elvira,Castellanos, J. Rubén Gómez,Mattevi, Andrea,Fraaije, Marco W.
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supporting information
p. 15852 - 15855
(2016/12/16)
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- E. coli cells expressing the Baeyer-Villiger monooxygenase 'MO14' (ro03437) from Rhodococcus jostii RHA1 catalyse the gram-scale resolution of a bicyclic ketone in a fermentor
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The Baeyer-Villiger monooxygenase (BVMO) 'MO14' from Rhodococcus jostii RHA1, is an enantioselective BVMO that catalyses the resolution of the model ketone substrate bicyclo[3.2.0]hept-2-en-6-one to the (1S,5R)-2-oxa lactone and the residual (1S,5R)-substrate enantiomer. This regio-plus enantioselective behaviour is highly unusual for BVMOs, which often perform enantiodivergent biotransformations of this substrate. The scaleability of the transformation was investigated using fermentor-based experiments, in which variables including gene codon optimisation, temperature and substrate concentration were investigated. E. coli cells expressing MO14 catalysed the resolution of bicyclo[3.2.0]hept-2-en-6-one to yield (1S,5R)-2-oxa lactone of >99% ee and (1S,5R)-ketone of 96% ee after 14 h at a temperature of 16 °C and a substrate concentration of 0.5 g L-1 (4.5 mM). MO14 is thus a promising biocatalyst for the production of enantio-enriched ketones and lactones derived from the [3.2.0] platform.
- Summers, Benjamin D.,Omar, Muhiadin,Ronson, Thomas O.,Cartwright, Jared,Lloyd, Michael,Grogan, Gideon
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supporting information
p. 1897 - 1903
(2015/02/19)
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- Functional divergence between closely related Baeyer-Villiger monooxygenases from Aspergillus flavus
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Baeyer-Villiger monooxygenases (BVMOs) catalyse the chemo-, regio- and enantioselective oxidation of ketones to esters and lactones. To date, most of the cloned BVMOs available are derived from bacteria, although Baeyer-Villiger oxidations using fungi have frequently been demonstrated. Here we report the cloning and characterization of four BVMOs from the fungus Aspergillus flavus NRRL3357. Phylogenetic analysis shows these four BVMOs to cluster in a distinct group apart from other well-characterized BVMOs including cyclohexanone, phenylacetone and 4-hydroxyacetophenone monooxygenase. Building on the Grogan classification/clustering of BVMOs, we have designated this new group of BVMOs, Group VI. Group VI BVMOs show an early divergence from the cyclopentanone monooxygenase (CPMO) type BVMOs (Group I). Substrate profiling using cyclic, bicyclic, aliphatic and aryl ketones show a clear divergence in function and specificity not only between this new group of BVMOs and the CPMO-type BVMOs, but also between the four A. flavus BVMO paralogues despite their high sequence similarity. This study not only contributes to the growing number of available BVMOs, but also addresses the current classification of Type I BVMOs, and the usefulness of phylogenetic clustering and prediction of function and selectivity when genome-mining is used to search for new biocatalysts.
- Ferroni,Smit,Opperman
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- Cloning and expression of a Baeyer-Villiger monooxygenase oxidizing linear aliphatic ketones from Dietzia sp. D5
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A Baeyer-Villiger monooxygenase has been identified in the genome sequence of Dietzia sp. D5. Sequence similarity search revealed that the enzyme belongs to a group of BVMOs that are closely related to ethionamide monooxygenase from Mycobacterium tuberculosis (EthA). The BVMO was expressed in E. coli BL21-CodonPlus(DE3)-RP and the best expression was achieved when the E. coli cells were cultivated in terrific broth (TB) at 15 °C and induced with 0.1 mM of IPTG. Since the purified enzyme did not show any measurable activity, the substrate scope of the BVMO has been determined using whole-cell and crude cell extract systems. The enzyme was most active towards linear aliphatic substrates. However, it has shown a moderate degree of conversion for cyclobutanone, 2-methylcyclohexanone, bicyclo[3.2.0]hept-2-en-6-one, phenylacetone and thioanisole. There was no detectable conversion of ethionamide, cyclohexanone and acetophenone.
- Bisagni, Serena,Smus?, Justyna,Chávez, Georgina,Hatti-Kaul, Rajni,Mamo, Gashaw
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p. 161 - 169
(2014/12/11)
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- Type II flavin-containing monooxygenases: A new class of biocatalysts that harbors baeyer-villiger monooxygenases with a relaxed coenzyme specificity
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Within a newly identified set of flavin-containing monooxygenases (FMOs) from Rhodococcus jostii RHA1, we have identified three monooxygenases (FMO-E, FMO-F, and FMO-G) that are effective in catalyzing Baeyer-Villiger oxidations. These type II FMOs display relaxed coenzyme specificity by accepting both NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) and NADH (reduced form of nicotinamide adenine dinucleotide), as a coenzyme, which is a novel and attractive feature among biocatalysts capable of conducting Baeyer-Villiger oxidations. We purified FMO-E and determined that the Michaelis constants for both coenzymes were in the micromolar range, whereas the activity was highest for NADH. By using the stopped-flow technique, formation of a peroxyflavin-enzyme intermediate was observed, which indicated that type II FMOs follow a catalytic mechanism similar to that of other class B flavoprotein monooxygenases. A set of cyclobutanones and cyclohexanones were used to probe the regio- and enantioselectivity of all three recombinant monooxygenases. The biocatalysts readily accepted small cyclic ketones, which enabled the conversion of previously poorly accepted substrates by other monooxygenases (especially norcamphor), and exhibited excellent and unique regio- and enantioselectivities. Sequence analysis revealed that type II FMOs that act as Baeyer-Villiger monooxygenases contain a unique N-terminal domain. Sequence conservation in this protein domain can be used to identify new NADH-dependent Baeyer-Villiger monooxygenases, which would facilitate future biocatalyst discovery efforts. New kid on the block: Members of a newly recognized group of sequence-related flavin-containing monooxygenases can perform Baeyer-Villiger oxidations. Their coenzyme indifference and unique specificity make them attractive biocatalysts.
- Riebel, Anette,Fink, Michael J.,Mihovilovic, Marko D.,Fraaije, Marco W.
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p. 1112 - 1117
(2014/05/06)
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- Jatrophane diterpenes: Preparation of the western fragment of pl-3
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Jatrophane diterpenes are structurally intriguing natural products with promising biological properties. Herein, the synthesis of the western fragment of the Euphorbiaceae constituent Pl-3 starting from (1R,5S)-bicyclo[3.2.0]hept- 2-en-6-one is described. Key steps in the sequence include a Baeyer-Villiger oxidation, an iodolactonization reaction, and the installation of the northern side chain through the addition of a lithiated vinyl bromide. The overall efficiency of the route is increased by taking advantage of latent symmetry. The synthesis of the western fragment of Pl-3 is developed by taking advantage of the latent symmetry in an intermediate; both enantiomers are thus converted into the desired substrate. Key steps of the synthesis include a Baeyer-Villiger oxidation, an iodolactonization reaction, and the addition of a vinyllithium species to the completed cyclopentane moiety of the natural product.
- Lentsch, Christoph,Fuerst, Rita,Mulzer, Johann,Rinner, Uwe
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p. 919 - 923
(2014/03/21)
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- PREPARATION OF LUBIPROSTONE
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Aspects of the present application relate to process for the preparation of lubiprostone.
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Paragraph 0110
(2013/07/25)
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- METHOD FOR MANUFACTURING ESTER
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The present invention relates to a method for manufacturing an ester from a ketone or an aldehyde, which is a reactive substrate, by a Baeyer-Villiger oxidation reaction using hydrogen peroxide, and in this method, as a catalyst, M(BAr4)n, which is a metal borate, is used (M represents an alkali metal or an alkaline earth metal; Ar represents an aryl; and n is the same number as the valence of M). For example, when cyclohexanone was used as the reactive substrate, and Sr[B(3,5-CF3C6H3)4]2 was used as the catalyst, ε-caprolactone was obtained at an isolated yield of 82%.
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Paragraph 0064; 0070; 0075; 0097
(2013/08/28)
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- Expanding the biocatalytic toolbox of flavoprotein monooxygenases from Rhodococcus jostii RHA1
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With the aim to enlarge the set of available flavoprotein monooxygenases, we have cloned 8 unexplored genes from Rhodococcus jostii RHA1 that were predicted to encode class B flavoprotein monooxygenases. Each monooxygenase can be expressed as soluble protein and has been tested for conversion of sulfides and ketones. Not only enantioselective sulfoxidations, but also enantioselective Baeyer-Villiger oxidations could be performed with this set of monooxygenases. Interestingly, in contrast to known class B flavoprotein monooxygenases, all studied biocatalysts showed no nicotinamide coenzyme preference. This feature coincides with the fact that the respective sequences appear to form a discrete group of sequence related proteins, distinct from the known class B flavoprotein monooxygenases subclasses: the so-called flavin-containing monooxygenases (FMOs), N-hydroxylating monooxygenases (NMOs) and Type I Baeyer-Villiger monooxygenases (BVMOs). Taken together, these data reveal the existence of a new subclass of class B flavoprotein monooxygenases, which we coined as Type II FMOs, that can perform Baeyer-Villiger oxidations and accept both NADPH and NADH as coenzyme. The uncovered biocatalytic properties of the studied Type II FMOs make this newly recognized subclass of monooxygenases of potential interest for biocatalytic applications.
- Riebel, Anette,De Gonzalo, Gonzalo,Fraaije, Marco W.
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- Discovery of Baeyer-Villiger monooxygenases from photosynthetic eukaryotes
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Baeyer-Villiger monooxygenases are attractive "green" catalysts able to produce chiral esters or lactones starting from ketones. They can act as natural equivalents of peroxyacids that are the catalysts classically used in the organic synthesis reactions, consisting in the cleavage of CC bonds with the concomitant insertion of an oxygen atom. In this study, two type I BVMOs have been identified for the first time in photosynthetic eukaryotic organisms, the red alga Cyanidioschyzon merolae (Cm) and the moss Physcomitrella patens (Pp). A biocatalytic characterization of these newly discovered enzymes, expressed in recombinant forms, was carried out. Both enzymes could be purified as holo enzymes containing a FAD cofactor. Their thermostability was investigated and revealed that the Cm-BVMO is the most thermostable type I BVMO with an apparent melting temperature of 56 C. Substrate profiling revealed that both eukaryotic BVMOs accept a wide range of ketones which include aromatic, aliphatic, aryl aliphatic and bicyclic ketones. In particular, linear aliphatic ketones (C9 and C12), carrying the keto functionality in different positions, resulted to be the best substrates in steady state kinetic analyses. In order to restore the BVMO-typifying sequence motif in the Pp-BVMO, a mutant was prepared (Y160H). Intriguingly, this mutation resulted in higher activities on most tested substrates. The recombinant enzymes displayed kcat values in the 0.1-0.2 s-1 range, which is relatively low when compared with other known type I BVMOs. This may hint to a role in secondary metabolism in these photosynthetic organisms, though their exact function remains to be established.
- Beneventi, Elisa,Niero, Mattia,Motterle, Riccardo,Fraaije, Marco,Bergantino, Elisabetta
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p. 145 - 154
(2013/12/04)
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- Blending Baeyer-Villiger monooxygenases: Using a robust BVMO as a scaffold for creating chimeric enzymes with novel catalytic properties
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The thermostable Baeyer-Villiger monooxygenase (BVMO) phenylacetone monooxygenase (PAMO) is used as a scaffold to introduce novel selectivities from other BVMOs or the metagenome by structure-inspired subdomain exchanges. This yields biocatalysts with new
- Van Beek, Hugo L.,Gonzalo, Gonzalo De,Fraaije, Marco W.
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supporting information; experimental part
p. 3288 - 3290
(2012/05/04)
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- Baeyer-Villiger Oxidation of Cyclobutanones with 10-Methylacridinium as an Efficient Organocatalyst
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Baeyer-Villiger oxidation of cyclobutanones is achieved in current developed protocol with 10-methylacridinium perchlorate (AcrH +ClO4-) as a novel organocatalyst both with irradiation at room temperature and without irradiation at elevated temperature. Excellent yields of the corresponding lactones are obtained and the possible mechanism has been proposed.
- Xu, Hua-Jian,Zhu, Feng-Fei,Shen, Yong-Ya,Wan, Xin,Feng, Yi-Si
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supporting information; experimental part
p. 4145 - 4151
(2012/07/27)
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- A Flavoprotein Monooxygenase that Catalyses a Baeyer-Villiger Reaction and Thioether Oxidation Using NADH as the Nicotinamide Cofactor
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A gene from the marine bacterium Stenotrophomonas maltophilia encodes a 38.6 kDa FAD-containing flavoprotein (Uniprot B2FLR2) named S. maltophilia flavin-containing monooxygenase (SMFMO), which catalyses the oxidation of thioethers and also the regioselective Baeyer-Villiger oxidation of the model substrate bicyclo[3.2.0]hept-2-en-6-one. The enzyme was unusual in its ability to employ either NADH or NADPH as nicotinamide cofactor. The KM and kcat values for NADH were 23.7±9.1 μM and 0.029 s-1 and 27.3±5.3 μM and 0.022 s-1 for NADPH. However, kcat/KM value for the ketone substrate in the presence of 100 μM cofactor was 17 times greater for NADH than for NADPH. SMFMO catalysed the quantitative conversion of 5 mM ketone in the presence of substoichiometric concentrations of NADH with the formate dehydrogenase cofactor recycling system, to give the 2-oxa and 3-oxa lactone products of Baeyer-Villiger reaction in a ratio of 5:1, albeit with poor enantioselectivity. The conversion with NADPH was 15%. SMFMO also catalysed the NADH-dependent transformation of prochiral aromatic thioethers, giving in the best case, 80% ee for the transformation of p-chlorophenyl methyl sulfide to its R enantiomer. The structure of SMFMO reveals that the relaxation in cofactor specificity appears to be accomplished by the substitution of an arginine residue, responsible for recognition of the 2′-phosphate on the NADPH ribose in related NADPH-dependent FMOs, with a glutamine residue in SMFMO. SMFMO is thus representative of a separate class of single-component, flavoprotein monooxygenases that catalyse NADH-dependent oxidations from which possible sequences and strategies for developing NADH-dependent biocatalysts for asymmetric oxygenation reactions might be identified.
- Jensen, Chantel N.,Cartwright, Jared,Ward, Jonathan,Hart, Sam,Turkenburg, Johan P.,Ali, Sohail T.,Allen, Michael J.,Grogan, Gideon
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experimental part
p. 872 - 878
(2012/07/27)
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- Pyrazinium salts as efficient organocatalysts of mild oxidations with hydrogen peroxide
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A series of 3-substituted pyrazinium tetrafluoroborates was prepared as simple analogues of flavinium salts which are efficient organocatalysts for oxidations with hydrogen peroxide. It was shown that pyrazinium derivatives with an electron-withdrawing su
- Menova, Petra,Kafka, Frantisek,Dvorakova, Hana,Gunnoo, Smita,Sanda, Miloslav,Cibulka, Radek
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experimental part
p. 865 - 870
(2011/06/23)
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- Asymmetric baeyer-villiger oxidation of 2,3- and 2,3,4-substituted cyclobutanones catalyzed by chiral phosphoric acids with aqueous H 2O2 as the oxidant
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Catalytic asymmetric Baeyer-Villiger (B-V) oxidation of 2,3,4-trisubstituted cyclobutanone (4) has been realized by the catalysis of a 1,1′-bi-2-naphthol (BINOL)-derived chiral phosphoric acid (1j), which contains bulky 2,4,6-triisopropyl phenyl groups at the 3,3′-positions of the BINOL backbone, using 30% aqueous H2O2 as the oxidant, affording the corresponding Iγ-lactone (5) in 99% yield with 95% ee. In a divergent kinetic resolution of racemic 2,3-disubstituted bicyclic cyclobutanones (6) through asymmetric B-V oxidation, the chiral phosphoric acid 1p demonstrated excellent catalytic performance, giving a range of regioisomeric chiral lactones in a normal lactone (nl)/abnormal lactone (al) ratio of up to 2.1:1, with up to 99% ee in the al product. It was found that fine tuning of the stereoelectronic properties of the backbone in chiral phosphoric acids is critically important for attaining high levels of enantioselectivity in the catalysis of B-V reactions of different type of cyclobutanones. The present work has provided a convenient approach to the synthesis of a variety of optically active chiral Iγ-lactones. Asymmetric Baeyer-Villiger oxidation of tricyclic cyclobutaone and a variety of racemic bicyclic cyclobutanone derivatives has been realized by the catalysis of 1,1′-bi-2-naphthol (BINOL)-derived chiral phosphoric acid with high yields and excellent enantioselectivities using 30% aqueous H2O2 as the oxidant.
- Xu, Senmiao,Wang, Zheng,Zhang, Xumu,Ding, Kuiling
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supporting information; experimental part
p. 110 - 116
(2011/03/21)
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- Asymmetric Baeyer-Villiger oxidation with Co(Salen) and H2O 2 in water: Striking supramolecular micelles effect on catalysis
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A micellar environment enables catalytic, diastereoselective and enantioselective Baeyer-Villiger oxidation of cyclobutanones (ee up to 90%) with H2O2 as oxidant using Co(Salen) catalyst 1, while the same catalytic system is inactive in organic solvents. The Royal Society of Chemistry 2009.
- Bianchini, Giulio,Cavarzan, Alessandra,Scarso, Alessandro,Strukul, Giorgio
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experimental part
p. 1517 - 1520
(2010/06/13)
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- Laboratory evolution of robust and enantioselective Baeyer-Villiger monooxygenases for asymmetric catalysis
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The Baeyer-Villiger Monooxygenase, Phenylacetone Monooxygenase (PAMO), recently discovered by Fraaije, Janssen, and co-workers, is unusually thermostable, which makes it a promising candidate for catalyzing enantioselective Baeyer-Villiger reactions in organic chemistry. Unfortunately, however, its substrate scope is very limited, reasonable reaction rates being observed essentially only with phenylacetone and similar linear phenyl-substituted analogs. Previous protein engineering attempts to broaden the range of substrate acceptance and to control enantioselectivity have been met with limited success, including rational design and directed evolution based on saturation mutagenesis with formation of focused mutant libraries, which may have to do with complex domain movements. In the present study, a new approach to laboratory evolution is described which has led to mutants showing unusually high activity and enantioselectivity in the oxidative kinetic resolution of a variety of 2-aryl and 2-alkylcyclohexanones which are not accepted by the wild-type (WT) PAMO and of a structurally very different bicyclic ketone. The new strategy exploits bioinformatics data derived from sequence alignment of eight different Baeyer-Villiger Monooxygenases, which in conjunction with the known X-ray structure of PAMO and induced fit docking suggests potential randomization sites, different from all previous approaches to focused library generation. Sites harboring highly conserved proline in a loop of the WT are targeted. The most active and enantioselective mutants retain the high thermostability of the parent WT PAMO. The success of the "proline" hypothesis in the present system calls for further testing in future laboratory evolution studies.
- Reetz, Manfred T.,Wu, Sheng
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supporting information; experimental part
p. 15424 - 15432
(2010/02/16)
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- Catalytic asymmetric Baeyer-Villiger oxidation in water by using Pt IIcatalysts and hydrogen peroxide: Supramolecular control of enantioselectivity
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The enantioselective BaeyerVilliger oxidation of cyclic ketones is a challenging reaction, especially when using environmentally friendly oxidants. The reaction was carried out in water by using soft Lewis acid PtII complexes that have chiral diphosphines as well as monophosphines. Addition of a surfactant is crucial, which leads to the formation of micelles that act as nanoreactors in which the substrate and catalyst encounter each other in an ordered medium that in several cases positively influences both the conversion and the selectivity of the reactions. This is due to the combination of the hydrophobic effect (which confines the components of the reaction in the micelles), together with supramolecular interactions between the partners within the ordered palisade provided by the alkyl chains of the surfactant. For the oxidation of wieso-cyclobutanones, addition of surfactant allowed the reaction to proceed in high yields and the enantiometic excess (ee; 56%) was higher than in organic solvents. Subsequent extension to meso-cyclohexanones resulted in a general decrease in yields but an enhancement of enantioselectivity (ee up to 92%) moving from organic to water-surfactant media, regardless of the substrate or the catalyst employed. Different behaviour was observed with chiral cyclobutanones 7 and 10: with 7 the best catalyst was 1g, whereas with the larger substrate, 10, complexes 1a-b performed better in terms of enantioselectivity. Each combination of substrate, catalyst and surfactant is a new system and supramolecular reciprocal interactions together with the hydrophobic character of the counterparts play crucial roles. The asymmetric Baeyer-Villiger oxidation in water catalyzed by 1a-h in the presence of micelles is a viable reaction that often benefits from the hydrophobic effect, leading to substantial increases in enantioselectivity.
- Cavarzan, Alessandra,Bianchini, Giulio,Sgarbossa, Paolo,Lefort, Laurent,Gladiali, Serafino,Scarso, Alessandro,Strukul, Giorgio
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scheme or table
p. 7930 - 7939
(2010/03/31)
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- Self-sufficient Baeyer-Villiger monooxygenases: Effective coenzyme regeneration for biooxygenation by fusion engineering
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(Chemical Presented) Two-in-one biocatalysts were engineered by the covalent fusion of NADPH-dependent Baeyer-Villiger monooxygenases to a phosphite dehydrogenase for coenzyme regeneration (see scheme). Not only the purified fusion proteins, but also whole cells and crude cell extracts containing the enzyme conjugates, could be used to catalyze biotransformations with high efficiency. NADP+=nicotinamide adenine dinucleotide phosphate.
- Torres Pazmino, Daniel E.,Snajdrova, Radka,Baas, Bert-Jan,Ghobrial, Michael,Mihovilovic, Marko D.,Fraaije, Marco W.
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supporting information; scheme or table
p. 2275 - 2278
(2009/02/08)
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- A light-driven stereoselective biocatalytic oxidation
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Let the sunshine in: Light can be used to drive enantioselective Baeyer-Villiger oxidations of cyclic ketones catalyzed by a flavin-dependent enzyme. Photochemical reduction of the flavin using ethylenediaminetetraacetate (EDTA) as the sacrificial electron donor closes the catalytic cycle, thus providing a means to directly regenerate reduced flavin cofactors without the need for costly nicotinamide cofactors as electron donors. (Chemical Equation Presented).
- Hollmann, Frank,Taglieber, Andreas,Schulz, Frank,Reetz, Manfred T.
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p. 2903 - 2906
(2008/03/13)
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- An aerobic, organocatalytic, and chemoselective method for Baeyer-Villiger oxidation
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(Chemical Equation Presented) Highly chemoselective Baeyer-Villiger oxidations can be performed in the presence of other reactive functionalities such as alcohols, olefins, and sulfides, which would undergo electrophilic oxidation under conventional conditions (see scheme). [DMRFlEt] +[ClO4]- (depicted blue) is a new class of flavin compound that catalyzes aerobic Baeyer-Villiger oxidations in the presence of Zn dust as the electron source.
- Imada, Yasushi,Iida, Hiroki,Murahashi, Shun-Ichi,Naota, Takeshi
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p. 1704 - 1706
(2007/10/03)
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- Microbiological transformations 57. Facile and efficient resin-based in situ SFPR preparative-scale synthesis of an enantiopure unexpected lactone regioisomer via a baeyer-villiger oxidation process
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Equation presented. The microbiological Baeyer-Villiger oxidation of (-)-bicyclo[3.2.0]hept-2-en-6-one allowed exclusive formation of the unexpected lactone regioisomer in 84% yield, high chemical purity, and enantiopure form. Substrate (25 g) was transformed in a 1 L bubble column reactor, following a in situ substrate feeding/product removal methodology, which afforded high volumetric productivity (1.2 g L-1 h -1). This illustrates the high sustainable chemistry advantages of such a process, simply conducted in aqueous medium, at room temperature and using atmospheric oxygen.
- Hilker, Iris,Gutierrez, Maria C.,Alphand, Veronique,Wohlgemuth, Roland,Furstoss, Roland
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p. 1955 - 1958
(2007/10/03)
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- A short stereoselective synthesis of (+)- and (-)-2-oxabicyclo[3.3.0]oct-6-en-3-one by intramolecular carbon-hydrogen insertion catalyzed by chiral dirhodium(II) carboxamidates
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The synthesis of (1S,5R)-(-)-2-oxabicyclo[3.3.0]oct-6-en-3-one, a useful synthetic precursor en route to various prostaglandins, from divinylcarbinol via catalytic metathesis and C-H insertion of 3-cyclopentenyl diazoacetate is described. Enantioselectivities of 90±1% have been achieved in the insertion process.
- Doyle, Michael P.,Catino, Arthur J.
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p. 925 - 928
(2007/10/03)
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- Selective and shape-selective Baeyer-Villiger oxidations of aromatic aldehydes and cyclic ketones with Sn-beta zeolites and H2O2
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Sn-Beta is used as a heterogeneous catalyst for the Baeyer-Villiger reaction with hydrogen peroxide. Cyclic ketones are transformed into the corresponding lactones, while unsaturated ketones are oxidized to the corresponding unsaturated lactones with very high chemoselectivity. The catalyst is also selective for the oxidation of aromatic aldehydes with H2O2, producing the formate ester or the corresponding hydrolyzed product, that is the alcohol. Shape-selective oxidations are observed for isomeric reactants with different molecular shapes. The catalytic Sn sites have been characterized by 119Sn MAS-NMR spectroscopy, and tetrahedral incorporation into the zeolite framework has been demonstrated. In situ IR spectroscopy and 18O labeling experiments have shown that the oxidation mechanism involves an intermediate of the Criegee type.
- Renz, Michael,Blasco, Teresa,Corma, Avelino,Fornes, Vicente,Jensen, Robert,Nemeth, Laszlo
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p. 4708 - 4717
(2007/10/03)
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- Identification of novel mammalian squalene synthase inhibitors using a three-dimensional pharmacophore
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Squalene synthase (E.C. 2.5.1.21) catalyses the reductive dimerisation of farnesyl diphosphate in a [1-4] head to head fashion to form squalene, and is the first committed step in cholesterol biosynthesis. Specific inhibitors of squalene synthase would inhibit cholesterol formation and allow production of other important compounds derived from the cholesterol biosynthetic pathway, namely the ubiquinones (co-enzyme Q10), dolichol, and would also allow the isoprenylation process of ras by farnesyl-protein transferase. The construction of a hypothetical squalene synthase three-dimensional pharmacophore is presented. It serves as a template for the identification of several new potential classes of inhibitors. The synthesis, anti-microbial and mammalian pig liver squalene synthase activities of analogues based on the bicyclo[3.2.0]heptane and bicyclo[3.3.0]octane ring systems are reported. Analogues of the latter system are pro-drug type inhibitors and exhibit promising biological activity.
- Fairlamb, Ian J.S.,Dickinson, Julia M.,O'Connor, Rachael,Higson, Seamus,Grieveson, Lynsey,Marin, Veronica
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p. 2641 - 2656
(2007/10/03)
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- Preparation of TADOOH, a hydroperoxide from TADDOL, and use in highly enantioface- and enantiomer-differentiating oxidations
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Replacement of one OH group in TADDOL ( = a,a,a′,a′-tetraaryl-1,3-dioxolane-4.5-dimethanol) by an OOH group gives a stable, crystalline chiral hydroperoxy alcohol TADOOH ( = [(4R,5R)-5-[(hydroperoxydiphenyl)methyl]-2,2-dimethyl-1,3-dioxolan-4-yl] diphenylmethanol) 3, the crystal structure of which resembles those of numerous other TADDOL derivatives (Fig. 2). The new hydroperoxide was tested as chiral oxidant in three types of reactions: the epoxidation of enones with base catalysis (Scheme 2), the sulfoxidation of methyl phenyl sulfide (Scheme 3), and the Baeyer-Villiger oxidation of bicyclic and tricyclic cyclobutanones, rac-10a-d with kinetic resolution (Scheme 4, Fig. 3, and Table). Products of up to 99% enantiomer purity were isolated (the highest values yet observed for oxidations with a chiral hydroperoxide!). Mechanistic models are proposed for the stereochemical courses of the three types of reactions (Schemes 5 and 6, and Fig. 4). Results of AM1 calculations of the relative transition-state energies for the anionic rearrangements of the exo Criegee adducts of TADOOH to the enantiomeric bicyclo[3.2.0]heptan-6-ones are in qualitative agreement with the observed relative rates (Table and Fig. 5).
- Aoki, Masao,Seebach, Dieter
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p. 187 - 207
(2007/10/03)
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- Chiral aluminum complexes as catalysts in asymmetric Baeyer-Villiger reactions of cyclobutanones
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BINOL-aluminum complexes were successfully employed as mediators and catalysts in asymmetric Baeyer-Villiger rearrangements of cyclobutanones. Good enantioselectivies were achieved with only 15 mol% of the chosen chiral Lewis acid. The enantiomeric excesses obtained have never been reached before in such metal-catalyzed Baeyer-Villiger reactions.
- Bolm, Carsten,Beckmann, Oliver,Palazzi, Chiara
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p. 1593 - 1597
(2007/10/03)
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- Electron deficient flavin as catalyst for baeyer-villiger reaction: Oxidation of cyclobutanones to γ-lactones using hydrogen peroxide
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The use of an electron deficient isoalloxazine derivative as coenzyme model for the Baeyer-Villiger oxidation is described. This allows, in the presence of hydrogen peroxide, the catalytic oxidation of cyclobutanones into the corresponding γ-lactones with good to excellent yields.
- Mazzini, Claudio
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p. 1161 - 1167
(2007/10/03)
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- Biological Baeyer-Villiger Oxidation of Some Monocyclic and Bicyclic Ketones using Monooxygenases from Acinetobacter calcoaceticus NCIMB 9871 and Pseudomonas putida NCIMB 10007
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A. calcoaceticus NCIMB 9871 and Ps. putida NCIMB 10007 have been utilized as biocatalysts in Baeyer-Villiger oxidations.The former microorganism oxidized the racemic ketone 6 non-selectively but transformed the dihalogeno ketone (+/-)-8 into optically active lactone 10 and recovered ketone.Ps. putida NCIBM 10007 oxidized the two enantiomers of the ketone 6 at different rates while both enantiomers of ketone (+/-)-1 were converted into lactones, one enantiomer giving 3-oxabicyclooctenone preferentially, while the other enantiomer gave 2-oxabicyclooctenone.Ps. putida NCIMB 10007 contains two quite different types of monooxygenase enzyme, one using NADH as cofactor (labelled MO1) the other employing NADPH as cofactor (labelled MO2).Monooxygenase MO1 proved to be a selective efficient biocatalyst for the oxidation of bicyclic ketones such as 1 and 6 while monooxygenase MO2 is a useful catalyst for the oxidation of cyclopentanones 15 - 17.Cofactor recycling was effected using dehydrogenase enzymes in preparative-scale experiments.
- Gadnon, Rene,Grogan, Gideon,Levitt, Melissa S.,Roberts, Stanley M.,Wan, Peter W. H.,Willetts, Andrew J.
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p. 2537 - 2544
(2007/10/02)
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- Radical-Type Cyclization of Dienes, VI. - Substrate-Controlled Asymmetric Synthesis of (3aS,6aR)-(+)-3,3a,6,6a-Tetrahydro-2H-cyclopentafuran-2-one
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(R)-(-)-Carvone (1) was converted via straightforward reactions into 10-hydroxycarvone (4) which was cyclized to 5 via the mercury-mediated free-radical method.Periodate cleavage of 5 yields the bicyclic dione.Regio- and stereoselective reduction of 6 with lithium tri(tert-butyloxy)hydridoaluminate results in 7 (80percent yield). 7 was directly converted into γ-lactone 8 via Baeyer-Villiger oxidation.Saponification of 8 to 9, mesylation of 9 to 10 followed by elimination of methanesulfonic acid yield enantiomerically pure (3aS,6aR)-(+)-3,3a,6,6a-tetrahydro-2H-cyclopentafuran-2-one (11).The synthesis can be carried out with readily available, and economical, (S)-(+)-carvone to yield ent-11.Key Words: Cyclopentafuran-2-one, (2aS,6aR)-(+)-3,3a,6,6a-tetrahydro-2H- / Radicals / Cyclization / Carvone
- Weinges, Klaus,Schwarz, Georg
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p. 811 - 814
(2007/10/02)
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- Some Baeyer-Villiger Oxidations using a Monooxygenase Enzyme from Pseudomonas putida NCIMB 10007
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A monooxygenase from Pseudomonas putida NCIMB 10007 is shown to catalyse stereoselective Baeyer-Villiger-type oxidations on the bicyclic ketones 2, 7, 8 and 9.
- Grogan, Gideon,Roberts, Stanley M.,Willetts, Andrew J.
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p. 699 - 701
(2007/10/02)
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- Synthesis of both the enantiomers of methyl epijasmonate
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Both the pure enantiomers of methyl epijasmonate 1 with potato-tuber inducing activity were synthesized stereoselectively starting from 2-oxabicyclo[3.3.0]-oct-6-en-3-one 6 in 20% yield through 11 steps.
- Kitahara, Takeshi,Nishi, Tsunehiro,Mori, Kenji
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p. 6999 - 7006
(2007/10/02)
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- Microbial Oxidation of 7endo-Methylbicyclohept-2-en-6-one, 7,7-Dimethylbicyclohept-2-en-6-one and 2exo-Bromo-3endo-hydroxy-7,7-dimethylbicycloheptan-6-one using Acinetobacter NCIMB 9871
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A bio-Bayer-Villiger reaction using Acinetobacter NCIMB 9871 and the bicycloheptanone 2 provided the corresponding substituted oxabicyclooctanones 6 and 7.Similarly the ketones 3 and 9 furnished the lactones 8 and 10 respectively: the lactones 6, 7 and 10 were obtained in states of high optical purity.
- Carnell, Andrew J.,Roberts, Stanley M.,Sik, Vladimir,Willetts, Andrew J.
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p. 2385 - 2390
(2007/10/02)
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