- Asymmetric Synthesis of N-Substituted γ-Amino Esters and γ-Lactams Containing α,γ-Stereogenic Centers via a Stereoselective Enzymatic Cascade
-
γ-Amino esters and γ-lactams containing α,γ-stereogenic centers are widely used as chiral intermediates in various bioactive compounds, while their efficient synthesis remains a challenge. Herein, an enzymatic cascade reaction involving an ene reductase (
- Li, Ming,Cui, Yunfeng,Xu, Zefei,Chen, Xi,Feng, Jinhui,Wang, Min,Yao, Peiyuan,Wu, Qiaqing,Zhu, Dunming
-
p. 372 - 379
(2021/10/25)
-
- A robust and stereocomplementary panel of ene-reductase variants for gram-scale asymmetric hydrogenation
-
We report an engineered panel of ene-reductases (ERs) from Thermus scotoductus SA-01 (TsER) that combines control over facial selectivity in the reduction of electron deficient C[dbnd]C double bonds with thermostability (up to 70 °C), organic solvent tolerance (up to 40 % v/v) and a broad substrate scope (23 compounds, three new to literature). Substrate acceptance and facial selectivity of 3-methylcyclohexenone was rationalized by crystallisation of TsER C25D/I67T and in silico docking. The TsER variant panel shows excellent enantiomeric excess (ee) and yields during bi-phasic preparative scale synthesis, with isolated yield of up to 93 % for 2R,5S-dihydrocarvone (3.6 g). Turnover frequencies (TOF) of approximately 40 000 h?1 were achieved, which are comparable to rates in hetero- and homogeneous metal catalysed hydrogenations. Preliminary batch reactions also demonstrated the reusability of the reaction system by consecutively removing the organic phase (n-pentane) for product removal and replacing with fresh substrate. Four consecutive batches yielded ca. 27 g L?1 R-levodione from a 45 mL aqueous reaction, containing less than 17 mg (10 μM) enzyme and the reaction only stopping because of acidification. The TsER variant panel provides a robust, highly active and stereocomplementary base for further exploitation as a tool in preparative organic synthesis.
- Nett, Nathalie,Duewel, Sabine,Schmermund, Luca,Benary, Gerrit E.,Ranaghan, Kara,Mulholland, Adrian,Opperman, Diederik J.,Hoebenreich, Sabrina
-
-
- DIHYDROPYRIMIDINE DERIVATIVES AND USES THEREOF IN THE TREATMENT OF HBV INFECTION OR OF HBV-INDUCED DISEASES
-
Provided herein are dihydropyrimidine derivatives which are useful in the treatment of HBV infection or HBV-induced diseases, as well as pharmaceutical or medical applications thereof.
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-
Page/Page column 65-66
(2019/11/28)
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- Reductive Cyclization of Unactivated Alkyl Chlorides with Tethered Alkenes under Visible-Light Photoredox Catalysis
-
The chemical inertness of abundant and commercially available alkyl chlorides precludes their widespread use as reactants in chemical transformations. Presented in this work is a metallaphotoredox methodology to achieve the catalytic intramolecular reductive cyclization of unactivated alkyl chlorides with tethered alkenes. The cleavage of strong C(sp3)?Cl bonds is mediated by a highly nucleophilic low-valent cobalt or nickel intermediate generated by visible-light photoredox reduction employing a copper photosensitizer. The high basicity and multidentate nature of the ligands are key to obtaining efficient metal catalysts for the functionalization of unactivated alkyl chlorides.
- Claros, Miguel,Ungeheuer, Felix,Franco, Federico,Martin-Diaconescu, Vlad,Casitas, Alicia,Lloret-Fillol, Julio
-
supporting information
p. 4869 - 4874
(2019/03/17)
-
- Identification and Implementation of Biocatalytic Transformations in Route Discovery: Synthesis of Chiral 1,3-Substituted Cyclohexanone Building Blocks
-
Several biocatalytic approaches for the preparation of optically pure methyl 3-oxocyclohexanecarboxylates (S)-, (R)-1 and 3-oxocyclohexanecarbonitriles (S)-, (R)-2 have been successfully demonstrated. Screening of reaction-focused enzyme collections was used to identify initial hits using three enzymatic strategies. Reaction optimization and scale-up enabled the production of chiral intermediates for route scouting efforts on scales of up to 100 g. The enzymes applied in these processes (lipases, enoate reductases, and nitrilases) have been shown to be robust catalysts for drug manufacturing and represent a green alternative to conventional methods to access these chiral cyclohexanone building blocks.
- Hadi, Timin,D?az-Rodr?guez, Alba,Khan, Diluar,Morrison, James P.,Kaplan, Justin M.,Gallagher, Kathleen T.,Schober, Markus,Webb, Michael R.,Brown, Kristin K.,Fuerst, Douglas,Snajdrova, Radka,Roiban, Gheorghe-Doru
-
supporting information
p. 871 - 879
(2018/07/05)
-
- Organic dye-catalyzed radical ring expansion reaction
-
Herein, we reported an attractive method for synthesizing medium-sized rings that are catalyzed by erythrosine B under fluorescent light irradiation. This synthetic approach featured mild conditions, a facile procedure, a broad substrate scope, and modera
- Deguchi, Masato,Fujiya, Akitoshi,Yamaguchi, Eiji,Tada, Norihiro,Uno, Bunji,Itoh, Akichika
-
p. 15825 - 15830
(2018/05/04)
-
- Biocatalytic synthesis of chiral cyclic γ-oxoesters by sequential C-H hydroxylation, alcohol oxidation and alkene reduction
-
A three-step biocatalytic procedure is described for the conversion of methyl and ethyl cyclopentene- and cyclohexenecarboxylates into both the enantiomers of the corresponding chiral 3-oxoesters, which are useful building blocks for the synthesis of active pharmaceutical ingredients. The allylic hydroxylation of the starting cycloalkenecarboxylates is carried out by using R. oryzae resting cells entrapped in alginate beads, in acetate buffer solution at 25 °C. The oxidation of the intermediate allylic alcohols to unsaturated ketones, performed by the laccase/TEMPO system, and the ene-reductase mediated hydrogenation of the alkene bond were carried out in the same reaction vessel in a sequential mode at 30 °C. Being entirely biocatalytic, our multistep procedure provides considerable advantages in terms of selectivity and environmental impact over reported chemical methods.
- Brenna, Elisabetta,Crotti, Michele,Gatti, Francesco G.,Monti, Daniela,Parmeggiani, Fabio,Pugliese, Andrea,Tentori, Francesca
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p. 5122 - 5130
(2017/11/09)
-
- Biocatalytic access to nonracemic γ-oxo esters: Via stereoselective reduction using ene-reductases
-
The asymmetric bioreduction of α,β-unsaturated γ-keto esters using ene-reductases from the Old Yellow Enzyme family proceeds with excellent stereoselectivity and high conversion levels, covering a broad range of acyclic and cyclic derivatives. Various strategies were employed to provide access to both enantiomers, which are versatile precursors of bioactive molecules. The regioselectivity of hydride addition on di-activated alkenes was elucidated by isotopic labeling experiments and showed strong preference for the keto moiety as activating/binding group as opposed to the ester. Finally, chemoenzymatic synthesis of (R)-2-(2-oxocyclohexyl)acetic acid was achieved in high ee on a preparative scale combining enzymatic reduction followed by ester hydrogenolysis.
- Turrini, Nikolaus G.,Cioc, Rǎzvan C.,Van Der Niet, Daan J. H.,Ruijter, Eelco,Orru, Romano V. A.,Hall, Mélanie,Faber, Kurt
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p. 511 - 518
(2017/08/14)
-
- TRPV4 ANTAGONISTS
-
The present invention relates to spirocarbamate analogs, pharmaceutical compositions containing them and their use as TRPV4 antagonists.
- -
-
Paragraph 0104; 0105
(2016/08/23)
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- Electrochemical reduction of 1-bromomethyl-2-oxocycloalkane-1-carboxylates at silver cathodes in dimethylformamide: One-carbon ring-expansion reactions
-
Cyclic voltammetry and controlled-potential (bulk) electrolysis have been employed to investigate the separate electrochemical reductions of methyl 1-bromomethyl-2-oxocyclopentane-1-carboxylate (1) and ethyl 1-bromomethyl-2-oxocyclohexane-1-carboxylate (2) at silver cathodes in dimethylformamide (DMF) containing 0.10 M tetramethylammonium tetrafluoroborate (TMABF4). Oneelectron reductive cleavage of the carbon-bromine bond of each substrate yields a radical intermediate that undergoes a ring-expansion reaction, followed by hydrogen-atom abstraction from the solvent, to afford methyl 3-oxocyclohexane-1-carboxylate (3a) and ethyl 3-oxocycloheptane-1-carboxylate (3b), respectively, in good yield. Each substrate gives rise to three other products: (a) a debrominated analogue of each starting material, (b) a dimeric species formed via radical coupling, and (c) a species possessing an ester group extended by one carbon atom. Electrolyses of 1 and 2 done in the presence of D2O have revealed that carbanion intermediates result in small amounts from two-electron cleavage of carbon-bromine bonds. A mechanistic scheme, involving both radicals and carbanions, is proposed to account for the formation of the various products.
- Wappes, Ethan A.,Mubarak, Mohammad S.,Peters, Dennis G.
-
p. G122 - G127
(2015/04/14)
-
- TRPV4 ANTAGONISTS
-
The present invention relates to spirocarbamate compounds of Formula (I) in which R1, (R2)Y, R3, R4, X and A have the meanings given in the specification. The invention further provides pharmaceutical compositions containing the compounds or pharmaceutically acceptable salts thereof and relates to their use of these compounds as TRPV4 antagonists in treating or preventing conditions associated with TRPV4 imbalance.
- -
-
Page/Page column 62-63
(2013/03/26)
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- CYCLOALKYLNITRILE PYRAZOLE CARBOXAMIDES AS JANUS KINASE INHIBITORS
-
Cycloalkylnitrile pyrazole carboxamides as JAK inhibitors useful for the treatment of JAK-mediated diseases such as rheumatoid arthritis, asthma, COPD and cancer are provided.
- -
-
Page/Page column 89
(2013/04/10)
-
- Site-selective oxidation of unactivated C sp 3-H bonds with hypervalent iodine(III) reagents
-
By design: The site-selective oxidation of unactivated secondary C sp 3-H bonds was accomplished with hypervalent iodine(III) reagents and tert-butyl hydroperoxide (see scheme). The preparation and derivatization of the hypervalent iodine(III) reagent are simple, thus allowing the rational design of these reagents to optimize the site selectivity of the oxidation. Copyright
- Moteki, Shin A.,Usui, Asuka,Zhang, Tiexin,Solorio Alvarado, Cesar R.,Maruoka, Keiji
-
supporting information
p. 8657 - 8660
(2013/09/12)
-
- Designer cells for stereocomplementary de novo enzymatic cascade reactions based on laboratory evolution
-
Designer cells for a synthetic cascade reaction harnessing selective redox reactions were devised, featuring two successive regioselective P450-catalyzed CH-activating oxidations of 1-cyclohexene carboxylic acid methyl ester followed by stereoselective ol
- Agudo, Ruben,Reetz, Manfred T.
-
supporting information
p. 10914 - 10916
(2013/11/19)
-
- TRPV4 ANTAGONISTS
-
The present invention relates to spirocarbamate analogs, pharmaceutical compositions containing them and their use as TRPV4 antagonists.
- -
-
Page/Page column 64
(2013/02/28)
-
- NOVEL CYCLIC BENZIMIDAZOLE DERIVATIVES USEFUL ANTI-DIABETIC AGENTS
-
Novel compounds of the structural formula (I) are activators of AMP-protein kinase and are useful in the treatment, prevention and suppression of diseases mediated by the AMPK- activated protein kinase. The compounds of the present invention are useful in
- -
-
Page/Page column 73
(2011/09/30)
-
- Combined effects on selectivity in Fe-catalyzed methylene oxidation
-
Methylene C-H bonds are among the most difficult chemical bonds to selectively functionalize because of their abundance in organic structures and inertness to most chemical reagents. Their selective oxidations in biosynthetic pathways underscore the power of such reactions for streamlining the synthesis of molecules with complex oxygenation patterns. We report that an iron catalyst can achieve methylene C-H bond oxidations in diverse natural-product settings with predictable and high chemo-, site-, and even diastereoselectivities. Electronic, steric, and stereoelectronic factors, which individually promote selectivity with this catalyst, are demonstrated to be powerful control elements when operating in combination in complex molecules. This small-molecule catalyst displays site selectivities complementary to those attained through enzymatic catalysis.
- Chen, Mark S.,White, M. Christina
-
scheme or table
p. 533 - 571
(2010/10/05)
-
- Directed evolution of an enantioselective enoate-reductase: Testing the utility of iterative saturation mutagenesis
-
Directed evolution utilizing iterative saturation mutagenesis (ISM) has been applied to the old yellow enzyme homologue YqjM in the quest to broaden its substrate scope, while controlling the enantioselectivity in the bioreduction of a set of substituted cyclopentenone and cyclohexenone derivatives. Guided by the known crystal structure of YqjM, 20 residues were selected as sites for saturation mutagenesis, a pooling strategy based on the method of Phizicky [M. R. Martzen, S. M. McCraith, S. L. Spinelli, F. M. Torres, S. Fields, E. J. Grayhack, E. M. Phizicky, Science 1999, 286, 1153-1155] being used in the GC screening process. The genes of some of the hits were subsequently employed as templates for randomization experiments at the other putative hot spots. Both (R)-and (S)-selective variants were evolved using 3-methylcyclohexenone as the model substrate in the asymmetric bioreduction of the olefinic functionality, only small mutant libraries and thus minimal screening effort being necessary. Some of the best mutants also proved to be excellent catalysts when testing other prochiral substrates without resorting to additional mutagenesis/screening experiments. Thus, the results constitute an important step forward in generalizing the utility of ISM as an efficient method in laboratory evolution of enzymes as catalysts in organic chemistry.
- Bougioukou, J. Despina,Kille, Sabrina,Taglieber, Andreas,Reetz, Manfredt.
-
experimental part
p. 3287 - 3305
(2010/04/30)
-
- A catalytic enantioselective conjugate addition of cyanide to enones
-
The first synthetically useful catalytic enantioselective conjugate addition of cyanide to enones is described. The optimized conditions involved a Gd catalyst (5 or 10 mol %) derived from ligands 3 or 4 and a 1:1 ratio of TBSCN and 2,6-dimethylphenol. Th
- Tanaka, Yuta,Kanai, Motomu,Shibasaki, Masakatsu
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p. 6072 - 6073
(2008/12/20)
-
- Fluorine-substituted cyclofenil derivatives as estrogen receptor ligands: Synthesis and structure-affinity relationship study of potential positron emission tomography agents for imaging estrogen receptors in breast cancer
-
In a search for estrogen receptor (ER) ligands to be radiolabeled with fluorine-18 for imaging of ER-positive breast tumors with positron emission tomography (PET), we investigated cyclofenil analogues substituted at the C3 or C4 position of the cyclohexyl group. McMurry coupling of 4,4′- dihydroxybenzophenone with various ketones produced key cyclofenil intermediates, from which C3 and C4 substituents containing alkyl and various oxygen or fluorine-substituted alkyl groups were elaborated. Binding assays to both ERα and ERβ revealed that the C3 site is more tolerant of steric bulk and polar groups than the C4 site, consistent with a computational model of the ERα ligand binding pocket. Fluorine substitution is tolerated very well at some sites, giving some compounds having affinities comparable to or higher than that of estradiol. These fluoro and fluoroalkyl cyclofenils merit further consideration as fluorine-18 labeled ER ligands for PET imaging of ERs in breast tumors.
- Seo, Jai Woong,Comninos, John S.,Chi, Dae Yoon,Kim, Dong Wook,Carlson, Kathryn E.,Katzenellenbogen, John A.
-
p. 2496 - 2511
(2007/10/03)
-
- ANTIBACTERIAL COMPOUNDS
-
Cyclohexane and cyclohexene derivatives and pharmaceutically acceptable derivatives thereof useful in methods of treatment of bacterial infections in mammals, particularly man
- -
-
-
- Zinc- and indium-mediated ring-expansion reaction of α-halomethyl cyclic β-keto esters in aqueous alcohol
-
Radical ring-expansion reaction of various α-halomethyl cyclic β-keto esters and α-halomethyl benzocyclic β-keto esters and chain-extension reaction of α-halomethyl β-keto esters with zinc powder and indium powder in refluxing aqueous alcohol were carried
- Sugi, Masaaki,Sakuma, Daisuke,Togo, Hideo
-
p. 7629 - 7633
(2007/10/03)
-
- Silylated cyclohexadienes as new radical chain reducing reagents: Preparative and mechanistic aspects
-
Various silylated 1,4-cyclohexadienes are presented as superior tin hydride substitutes for the conduction of various radical chain reductions. Debrominations, deiodinations, and deselenations can be performed using these environmentally benign reagents. Furthermore, Barton - McCombie-type deoxygenations using silylated cyclohexadienes are described. Radical cyclizations, ring expansions, and Giesetype addition reactions with the new tin hydride substitutes are presented. The polymerization of styrene can be regulated using silylated cyclohexadienes. Rate constants for hydrogen atom abstraction from two 1-silyl-cyclohexadienes by primary C-radicals were determined. The effects of the cyclohexadiene substituents on the reaction outcomes are discussed. Finally, qualitative EPR experiments on silyl radical expulsion from silylated cyclohexadienyl radicals are presented.
- Studer, Armido,Amrein, Stephan,Schleth, Florian,Schulte, Tobias,Walton, John C.
-
p. 5726 - 5733
(2007/10/03)
-
- Novel access to cyclohexane-1,4-diones and 1,4-hydroquinones via radical 1,2-acyl rearrangement on 2-(halomethyl)cyclopentane-1,3-diones using cobaloxime-mediated electroreduction or tributyltin hydride
-
A new preparative access to synthetically useful cyclohexane-1,4-diones 2 and their oxidized analogues, hydroquinones 3, with the option of introducing alkyl and aryl substituents, was developed by radical 1,2-acyl rearrangement on 2-(halomethyl)cyclopentane-1,3-diones 1, accessible from 1,2-bis(trimethylsiloxy)cyclobutene and α-bromo ketone dimethyl acetals. The electroreduction of monoacetals of 1 in the presence of cobaloxime as a catalyst afforded the cyclohexane-1,4-dione monoacetals in good yields. The Bu3SnH-reduction of 2-aryl 1 under refluxing in benzene effected the rearrangement, affording 2, and when the reaction was prolonged, aromatization to 3 proceeded in moderate yields.
- Kawafuchi, Hiroyuki,Inokuchi, Tsutomu
-
p. 2051 - 2054
(2007/10/03)
-
- Environmentally friendly TPDS-mediated free radical ring expansion of α-haloalkyl cyclic β-keto esters
-
Reactivities of tetraphenyldisilane (TPDS), tris(trimethylsilyl)silane, and tributyltin hydride in the radical ring expansion of α-haloalkyl cyclic β-keto esters were examined. Among these reagents, TPDS was found most effective for the preparation of medium-sized cyclic compounds in terms of yields and ring-expansion/reduction selectivity.
- Sugi, Masaaki,Togo, Hideo
-
p. 3171 - 3175
(2007/10/03)
-
- Indium metal as a reducing agent. Selective reduction of the carbon-carbon double bond in highly activated conjugated alkenes
-
(Equation presented) Indium metal in aqueous ethanolic ammonium chloride reduces the C=C bond in highly activated conjugated alkenes such as α,α-dicyano olefins, β-arylenones, and enone esters.
- Ranu, Brindaban C.,Dutta, Jyotirmoy,Guchhait, Sankar K.
-
p. 2603 - 2605
(2007/10/03)
-
- Silylated cyclohexadienes: New alternatives to tributyltin hydride in free radical chemistry
-
An environmentally benign alternative to the toxic tin hydrides in radical chemistry is offered by the introduction of silylated cyclohexadienes 1. Most of the common radical reactions, such as dehalogenations, deselanations, deoxygenations, cyclizations, and intermolecular radical addition reactions can be conducted by using these readily available new reagents. X = Cl, Br, I, SePh, OCSOPh.
- Studer, Armido,Amrein, Stephan
-
p. 3080 - 3082
(2007/10/03)
-
- Tin-free radical chemistry: Intramolecular addition of alkyl radicals to aldehydes and ketones
-
The radical cyclization of several ω-iodoaldehydes and a ketone can be accomplished without the use of tributyltin hydride. Triethylborane in presence of oxygen or light from a sun lamp can serve as a radical initiator and terminator. In these conditions,
- Devin, Priscille,Fensterbank, Louis,Malacria, Max
-
p. 5511 - 5514
(2007/10/03)
-
- Reactions of 1-methoxycarbonyl-3-cyclohexene and 3,4-epoxy-1-methoxycarbonyl-cyclohexane with tert-butoxy radical
-
Reactions of 1-methoxycarbonyl-3-cyclohexene and 3,4-epoxy-1-methoxycarbonylcyclohexane (as a 63:37 mixture of trans and cis isomers or pure trans isomers) with tert-butoxy radical at 413 K yield oligomeric products. In the case of epoxy derivatives, 1-methoxycarbonyl-4-cyclohexen-3-ol, 1-methoxycarbonyl-4-cyclohexen-3-one, and 1-methoxycarbonyl-3-cyclohexanone are also formed. This set of products indicates that tert-butoxy radical abstracts a hydrogen atom from the 2-position of the cyclohexene ring and from the 2,3- or 4,5-positions of the cyclohexane ring. 1996 MAEe Cyrillic signΚ Hayκa/Interperiodica Publishing.
- Zaitseva,Narizhnaya
-
p. 480 - 485
(2007/10/03)
-
- Competition for Regiochemical Control between Substituents of Some 2,3-Disubstituted Buta-1,3-dienes in the Diels-Alder Reactions
-
Several 3,4-disubstituted 3-sulfolenes 1a-j, the precursors for the corresponding 2,3-disubstituted 1,3-dienes 2a-j, are conveniently prepared and undergo Diels-Alder reactions smoothly with methyl acrylate under thermal conditions where the order of para
- Chou, Ta-shue,Chang, Chin-Yao,Wu, Meng-Chu,Hung, Shao-Hwa,Liu, Hui-Ming,Yeh, Wen-Yuan
-
p. 1643 - 1644
(2007/10/02)
-
- Pericyclic Umpolung. Reversal of Regioselectivity in the Diels-Alder Reaction
-
New methodology is reported which enables reversal of regiochemistry in the Diels-Alder reaction.Esterification of 2-(β-hydroxyethyl)dimethylsilyldienes with common dienophiles followed by type 2 intramolecular Diely-Alder reaction results in formation of a single regio- and stereoisomer.Oxidative cleavage of the cycloadduct produces a cyclohexanone with a substitution pattern opposite of that found in the analogous bimolecular cycloaddition reaction.
- Shea, K. J.,Staab, Andrew J.,Zandi, Kathleen S.
-
p. 2715 - 2718
(2007/10/02)
-
- NOVEL FREE RADICAL RING-EXPANSION REACTIONS
-
A novel free radical initiated ring expansion of haloalkyl β-keto esters is described.Following alkylation of the β-keto ester with the appropriate dihalide, the resulting halide is treated at reflux with tri-n-butyltin hydride.Rearrangement to the homolo
- Dowd, Paul,Choi, Soo-Chang
-
-
- SPECIFITY OF E. COLI SHIKIMATE DEHYDROGENASE TOWARDS ANALOGUES OF 3-DEHYDROSHIKIMIC ACID
-
Analogues of 3-dehydroshikimic acid which lack the C-4 and C-5 hydroxyl groups have been synthesised and assayed as substrates for shikimate dehydrogenase.The presence of the C-4 hydroxyl group is found to be very important for specificity, whereas the C-5 hydroxyl group is not.The enzyme exhibits enantioselectivity at C-1 and C-4 of the racemic substrate analogues.
- Bugg, Timothy D. H.,Abell, Chris,Coggins, John R.
-
p. 6779 - 6782
(2007/10/02)
-
- Cyano or Acyl Group Migration by Consecutive Homolytic Addition and β-Fission
-
Suitably constituted aryl and alkyl radicals readily rearrange by 1,2- or 1,4-acyl or cyano migration.
- Beckwith, Athelstan L. J.,O'Shea, Dennis M.,Gerba, Sendaba,Westwood, Steven W.
-
p. 666 - 667
(2007/10/02)
-
- General Syntheses of 6- and 7-Carbomethoxy-trans-1-heteradecalins and 6- and 7-Carbomethoxy-trans-2-heteradecalins
-
Two routes to all of the title compounds in the oxa and aza series have been studied.The most general path, involving a cyclohexene oxide intermediate, was not successful becauase of difficulty in separating regioisomers.Allylation of 4-carbomethoxycyclohexanone (11) followed by reduction produced the required trans-disubstituted allyl alcohols, which were converted to all of the desired 6-carbomethoxy-trans-1-heteradecalins.The allyl ketones were subjected to a homologation-side chain contraction sequence to produce the 6-carbomethoxy-trans-2-heteradecalins.Allylation of 3-carbomethoxycyclohexanone (12) was not regioselective, but all four product isomers were characterized.The desired 5-carbomethoxy-2-allylcyclohexanone isomers (27 and 28) were converted to the 7-carbomethoxy-trans-decalins by similar series of reactions
- Hirsch, Jerry A.,Truc, Vu Chi
-
p. 2218 - 2227
(2007/10/02)
-
- Enzymatic in vitro Reduction of Ketones. Part 13. Horse Liver Alcohol Dehydrogenase (HLAD) as a Tool for the Synthesis of Enantiomerically Pure Alkyl 3-oxo- and 3-hydroxycyclohexanecarboxylates.
-
Enantiomerically pure alkyl 3-oxocyclohexanecarboxylates and the corresponding alcohols have been prepared using HLAD as a suitable catalyst.Kinetic and thermodynamic parameters for the enzymatic reductions are given.The enantiomeric purity and the absolute configuration of the reaction products are determined.The alcohol moiety (methyl, isopropyl or pentyl) of the ester group influences both the steric course and the kinetics of the reduction.Side reactions of the substrate with the reaction medium can be avoided by an appropriate choice of the reaction conditions.
- Willaert, J. J.,Lemiere, G. L.,Dommisse, R. A.,Lepoivre, J. A.,Alderweireldt, F. C.
-
p. 2401 - 2423
(2007/10/02)
-
- ENZYMATIC IN VITRO REDUCTION OF KETONES. PART 11. THE UNEXPECTED STERIC COURSE OF THE HLAD CATALYZED REDUCTION OF 3-CYANOCYCLOHEXANONE.
-
3-Cyanocyclohexanone is a suitable substrate for preparative HLAD reduction, delivering enantiomerically pure (1S,3S)-trans and (1R,3S)-cis alcohols.Details are given on the kinetics of the reduction and the absolute configuration of the products.In contr
- Willaert, Jan J.,Lemiere, Guy L.,Dommisse, Roger A.,Lepoivre, Joseph A.,Alderweireldt, Frank C.
-
p. 139 - 150
(2007/10/02)
-
- gem-Dichlorocyclopropanes as Masked Esters: A Novel Synthesis of β-Methoxycarbonyl Aldehydes and Ketones
-
The carbonyl conjugated gem-dichlorocyclopropanes (1) react with sodium methoxide in methanol affording β-methoxycarbonyl aldehydes and ketones in high yield.
- Banwell, Martin G.
-
p. 1453 - 1454
(2007/10/02)
-