- O-H hydrogen bonding promotes H-atom transfer from α C-H bonds for C-alkylation of alcohols
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The efficiency and selectivity of hydrogen atom transfer from organic molecules are often difficult to control in the presence of multiple potential hydrogen atom donors and acceptors. Here, we describe the mechanistic evaluation of a mode of catalytic activation that accomplishes the highly selective photoredox a-alkylation/lactonization of alcohols with methyl acrylate via a hydrogen atom transfer mechanism. Our studies indicate a particular role of tetra-n-butylammonium phosphate in enhancing the selectivity for α C-H bonds in alcohols in the presence of allylic, benzylic, α-C=O, and α-ether C-H bonds.
- Jeffrey, Jenna L.,Terrett, Jack A.,MacMillant, David W.C.
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- Mercapturic Acid Conjugates as Urinary End Metabolites of the Lipid Peroxidation Product 4-Hydroxy-2-nonenal in the Rat
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4-Hydroxy-2-nonenal (HNE), an aldehyde end product of lipid peroxidation in biological systems, is capable of producing a range of powerful biological effects. Despite its biological relevance, the metabolic fate of this aldehyde is unknown in vivo. This study examines the urinary excretion of HNE in the rat and the nature of metabolites formed. Following iv administration of HNE, the majority of the dose appeared in urine (67.1 percent after 48 h). The radio-HPLC metabolic profile showed that no unchanged parent compound was detected in urine whereas at least four metabolites were present, most of them corresponding to mercapturic acid conjugates. Two major pathways were involved in the biotransformation of HNE in vivo: (i) reduction/oxidation of the aldehyde group, and (ii) conjugation to endogenous glutathione leading to mercapturic acid conjugates in urine. These end products were isolated by HPLC and identified by mass spectrometry as HNE mercapturic acid, 1,4-dihydroxynonene mercapturic acid, 4-hydroxynonenoic mercapturic acid, and the corresponding lactone.
- Alary, Jacques,Bravais, Fabienne,Cravedi, Jean-Pierre,Debrauwer, Laurent,Rao, Dinesh,Bories, Georges
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- Conjugate Addition of gem-Borazirconocene Alkenes to Michael Acceptors
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gem-Borazirconocenes, 1, readily add across Michael acceptors in the presence of Cu(I)Br*SMe2, to afford 1,4-addition products in good to excellent yilds.In the case of cycloalkenones diastereomers are produced, with the anti product favored.The selectivity with cyclopentenone is high (9:1), while with cyclohexenone it is less (3:1).In the present context, gem-borazirconocene alkanes can be regarded as α-hydroxyl anion equivalents.
- Pereira, Schubert,Srebnik, Morris
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- Efficient and convenient preparation of γ-nonalactone, with use of a Dean-Stark trap to remove methanol
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We describe the development of an efficient and convenient process for preparation of γ-nonalactone. The synthesis was accomplished by free-radical addition of methyl acrylate and n-hexanol. A Dean-Stark trap filled with water and n-hexanol was used to remove the methanol generated during the process. Orthogonal experiments were performed to optimize the reaction conditions, and the desired product, γ-nonalactone, was produced in better than 70 % yield.
- Tu, Song,Shen, Youyu,Dong, Wan,Yang, Jing,Zhang, Chen,Ye, Liyi
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- A new coupling reaction between β-lactones and electrophiles mediated by a SmI2/(NiI2 catalytic) system
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β-lactones react with ketones aldehydes and imines in the presence of a SmI2/(NiI2 catalytic) system to afford substituted tetrahydrofuranones and pyrrolidinones.
- Machrouhi, Fouzia,Namy, Jean-Louis
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- Carbon-Carbon Bond Formation by the Use of Chloroiodomethane as a C1 Unit. II. The Preparation and Synthetic Application of 1-Chloro-3-iodoheptane
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Terminal alkenes, R-CH=CH2 (R=Et, n-Pr, n-Bu, N-Hex), were readily transformed into 1-chloro-3-iodoalkanes by the AIBN-induced free radical addition of chloroiodomethane.Thus, 1-chloro-3-iodoheptane was obtained from 1-hexene in an 88percent yield; this in turn was allowed to react with dialkyl malonates in the presence of alkoxides in alcohols to give dialkyl 2-butylcyclobutane-1,1-dicarboxylates and dialkyl (E)-3-octene-1,1-dicarboxylates (7), either of which could be obtained preferentially by the choice of the experimental parameters.The olefinic product, 7, was further utilized for the synthesis of (E)-5-decenyl acetate and/or 1,4-nonanolide.
- Miyano, Sotaro,Hokari, Hiroshi,Umeda, Yoshiharu,Hashimoto, Harukichi
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- Characterisation of a by-product formed in the industrial production of γ-nonalactone
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Distillation residues from the industrial production of γ-nonalactone, which is accomplished by reaction of hexanol with methyl acrylate initiated by t-butyl peroxide, yielded a by-product which we deduced to be 4-(methoxycarbonylethyl)-γ-nonalactone. The possible pathway of formation of this by-product is discussed.
- Chen, Haitao,Wang, Dan,Liu, Yongguo,Zhang, Guoying,Wang, Tianyi,Wang, Yang,Yang, Shaoxiang,Sun, Baoguo,Tian, Hongyu
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- Synthesis of (±)-4-alkanolides from pent-4-enoic acid
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Synthesis of (±)-4-hexanolide, (±)-4-nonanolide, and (±)-4-dodecanolide, racemic forms of the insect signal substances, has been accomplished by cationic cyclization of pent-4-enoic acid and its amide in the key step.
- Ugurchieva,Lozanova,Zlokazov,Veselovsky
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- Preparation method of coconut aldehyde
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The invention discloses a preparation method of coconut aldehyde. The method comprises the following steps: step 1, mixing n-hexanol, acrylic acid and di-tert-butyl peroxide with uniform stirring, andcarrying out heat insulation on an obtained mixed solution; step 2, mixing n-hexanol with a beta molecular sieve catalyst, performing stirring, heating and heat preservation in a nitrogen environment, dropwise adding the mixed solution obtained in the step 1 at a constant speed during the heat preservation, continuously separating out byproducts including water, tert-butyl alcohol and methanol inthe reaction process, and continuously performing reacting for 1-2 hours after dropwise adding is finished; and step 3, after the reaction is finished, performing cooling, recovering low-boiling-point substances and n-hexanol in the reaction solution in vacuum, performing cooling after the recovery is finished to obtain a crude product, and carrying out reduced pressure distillation on the crudeproduct to obtain a coconut aldehyde product. The novel environment-friendly high-efficiency beta molecular sieve catalyst adopted by the invention shows good catalytic activity and selectivity in coconut aldehyde synthesis, can be repeatedly used, can be cyclically regenerated in manners of high-temperature roasting and the like, and is high in reaction yield, and the technological process is easy to control, and is beneficial to forming industrial large-scale production.
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Paragraph 0017-0022
(2021/02/10)
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- Identification of Bond-Weakening Spirosilane Catalyst for Photoredox α-C?H Alkylation of Alcohols
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The development of catalyst-controlled site-selective C(sp3)?H functionalization is a current major challenge in organic synthesis. This paper describes DFT-guided identification of pentavalent silicate species as a novel bond-weakening catalyst for the α-C?H bonds of alcohols together with a photoredox catalyst and a hydrogen atom transfer catalyst. Specifically, Martin's spirosilane accelerated α-C?H alkylation of alcohols. (Figure presented.).
- Sakai, Kentaro,Oisaki, Kounosuke,Kanai, Motomu
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supporting information
p. 337 - 343
(2019/12/24)
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- A Bond-Weakening Borinate Catalyst that Improves the Scope of the Photoredox α-C-H Alkylation of Alcohols
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The development of catalyst-controlled, site-selective C(sp 3)-H functionalization reactions is currently a major challenge in organic synthesis. In this paper, a novel bond-weakening catalyst that recognizes the hydroxy group of alcohols through formation of a borate is described. An electron-deficient borinic acid-ethanolamine complex enhances the chemical yield of the α-C-H alkylation of alcohols when used in conjunction with a photoredox catalyst and a hydrogen atom transfer catalyst under irradiation with visible light. This ternary hybrid catalyst system can, for example, be applied to functional-group-enriched-peptides.
- Kanai, Motomu,Oisaki, Kounosuke,Sakai, Kentaro
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supporting information
p. 2171 - 2184
(2020/08/10)
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- Production method for synthesizing coconut aldehyde synthetic fragrance through reactive distillation
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The invention belongs to the technical field of fine chemical production, and specifically relates to a production method for synthesizing a coconut aldehyde synthetic fragrance through reactive distillation. The production method comprises the following steps: (a) mixing raw materials through a pipeline so as to obtain a batched mixture; (b) releasing hexanol into a preheater from the interior ofa hexanol high-level tank, and carrying out preheating; (c) pumping the hexanol into the high-boiling-point feeding section of the reaction zone of a reactive distillation tower, pumping the batchedmixture into the low-boiling-point feeding section of the reaction zone of the reactive distillation tower through a dropwise adding pump; (d) separating a crude coconut aldehyde product from the tower bottom of the reactive distillation tower; (e) transferring the hexanol separated in the step (d) into the preheater through a material pump, and allowing the hexanol to continue participating in areaction; and (f) further subjecting the separated crude coconut aldehyde product to separation and purification. The production method provided by the invention adopts a reactive distillation technology to separate by-products namely methanol and tert-butanol and low-boiling-point impurities generated by side reactions out of a reaction system in time, greatly shortens the reaction time, and improves the reaction speed and reaction efficiency.
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Paragraph 0039-0064
(2019/01/08)
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- Method for synthesizing coconut aldehyde synthetic spice through reactive distillation
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The invention belongs to the technical field of fine chemical engineering, and particularly relates to a method for synthesizing a coconut aldehyde synthetic spice through reactive distillation. The method comprises the following steps: (a) mixing hexyl alcohol, methyl acrylate and di-tert-butyl peroxide to obtain a mixture; (b) weighing hexyl alcohol, adding the hexyl alcohol into a heater of a reactive distillation tower, and putting the proportioned mixture obtained in the step (a) into a reaction area of the reactive distillation tower; (c) introducing condensate water at the tower top ofthe reactive distillation tower, and separating out a coconut aldehyde crude product from the tower bottom; and (d) transferring the coconut aldehyde crude product into a rotary evaporator, controlling the vacuum degree, the temperature and the rotating speed, and carrying out collecting to obtain the coconut aldehyde. According to the invention, a reactive rectification technology is adopted, andby-products are separated out from the reaction system in time, so that dual effects that separation is promoted by a reaction and the reaction is promoted by separation are achieved, the reaction efficiency is improved, and the reaction yield is ensured.
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Paragraph 0041-0057
(2019/01/08)
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- PROCESS FOR THE ELECTROCHEMICAL PREPARATION OF GAMMA-HYDROXYCARBOXYLIC ESTERS AND GAMMA-LACTONES
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γ-Hydroxycarboxylic esters and γ-lactones which are suitable as flavors can be prepared by electrochemical reductive cross-coupling of α,β-unsaturated esters with carbonyl compounds in an undivided electrolysis cell having a cathode composed of lead, lead alloys, cadmium, cadmium alloys, mercury, steel, glassy carbon or boron-doped diamonds and a basic aqueous electrolyte comprising an electrolyte salt which suppresses the cathodic formation of hydrogen.
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Paragraph 0054-0057
(2014/04/18)
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- An efficient oxidative lactonization of 1,4-diols catalyzed by Cp*Ru(PN) complexes
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An efficient oxidative lactonization of 1,4-diols in acetone is accomplished by the well-defined ruthenium catalyst, whose bifunctional nature underlies the high efficiency as well as unique chemo- and regioselectivity of the reaction which provides a rapid access to γ-butyrolactones including flavor lactones hinokinin, and muricatacin.
- Ito, Masato,Osaku, Akihide,Shiibashi, Akira,Ikariya, Takao
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p. 1821 - 1824
(2008/02/02)
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- PROCESSES FOR PRODUCING OXIDE WITH HIGHER OXIDATION THAN ALCOHOL
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The present invention provides a process for producing an oxide from an alcohol compound, the process comprising the steps of causing silica gel to carry the alcohol compound thereon and an oxidative catalyst thereon, and oxidizing the alcohol compound in the presence of an oxidizing agent, giving an oxide higher in oxidizing degree than the alcohol compound, and also provides a process for producing an oxide from an alcohol compound, the process comprising the steps of causing silica gel to carry the alcohol compound, and subjecting the alcohol compound to an electrolytic oxidation, giving an oxide higher in oxidizing degree than the alcohol compound.
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- Microbial bioreductions of γ- and δ-ketoacids and their esters
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A series of yeasts were used in the bioreductions of aliphatic and aromatic γ- and δ-ketoacids and esters to investigate the preparation of enantiomerically pure γ- and δ-lactones through the intermediacy of their corresponding γ- and δ-hydroxyacids and esters. Bioreduction of ethyl 4-oxononanoate 2a with Pichia etchellsii afforded the γ-nonanolide (+)-5a with 99% e.e., while Pichia minuta proved to be the best choice for the bioreduction of ethyl 2-oxocyclohexylacetate 2e, which afforded cis-(-)-5e and trans-(-)-5e with 98 and 99% e.e., respectively. Reduction of 3-(2-oxocyclohexyl)propionic acid 3e with Pichia glucozyma gave predominantly the corresponding δ-lactone trans-(-)-6e with 94% e.e., whose absolute configuration was determined by means of CD spectroscopy.
- Forzato, Cristina,Gandolfi, Raffaella,Molinari, Francesco,Nitti, Patrizia,Pitacco, Giuliana,Valentin, Ennio
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p. 1039 - 1046
(2007/10/03)
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- An aqueous silica gel disperse electrolysis system. N-Oxyl-mediated electrooxidation of alcohols
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N-Oxyl-mediated electrooxidation of alcohols was performed in an aqueous silica gel disperse system. The newly devised electrolysis system offers an organic solvent-free and operationally simple procedure for oxidation of alcohols and could be successfully applied to kinetic resolution of sec-alcohol as well as enantioselective oxidation of meso-1,4-diol affording optically active γ-lactone.
- Tanaka, Hideo,Kawakami, Yusuke,Goto, Kentaro,Kuroboshi, Manabu
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p. 445 - 448
(2007/10/03)
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- A NEW ROUTE TO γ-SUBSTITUTED γ-LACTONES AND δ-SUBSTITUTED δ-LACTONES BASED ON THE REGIOSELECTIVE β-SCISSION OF ALKOXY RADICALS GENERATED FROM TRANSANNULAR HEMIACETALS
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A new general synthesis of γ-substituted γ-lactones and δ-substituted δ-lactones including dihydro-5-octyl-2(3H)-furanone, a natural pheromone, is described.The synthesis involves the regioselective β-scission of alkoxy radicals generated from transannular hemiacetals as the key step. Key Words: γ-Lactones; δ-Lactones; Mercury(II) Oxide-Iodine Reagent; Photolysis; β-Scission of Alkoxyl Radicals
- Kobayashi, Kazuhiro,Sasaki, Akiyoshi,Kanno, Yoshikazu,Suginome, Hiroshi
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p. 7245 - 7258
(2007/10/02)
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- N-Benzyl-3-(tri-n-butylstannyl)thiopropionamide as Thiohomoenolatesynthon. Application to a Synthesis of Some Heterocycles
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N-Benzyl-3-(tri-n-butylstannyl)thiopropionamide undergoes metalexchange with n-butyllithium.The resulting thiohomoenolate dianion reacts with elestrophiles (aldehydes and ketones) to give the γ-hydroxythioamides, which are transformed into lactones, iminothiolactones, and thiolactams with simple elaboration.
- Takahata, Hiroki,Ohkura, Etsuko,Ikuro, Kazumi,Yamazaki, Takao
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p. 285 - 292
(2007/10/02)
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- An Efficient Route for γ-Alkyl-γ-butyrolactones
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An efficient route for γ-alkyl-γ-butyrolactones (1) involving iodolactonisation is described.
- Gurjar, M. K.,Purandare, A. V.
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p. 554 - 555
(2007/10/02)
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- Samarium(II) Di-iodide Induced Reductive Coupling of α,β-Unsaturated Esters with Carbonyl Compounds Leading to a Facile Synthesis of γ-Lactone
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Samarium(II) di-iodide, which is a strong one-electron transfer reducing agent, is effective for the reductive coupling of α,β-unsaturated esters with carbonyl compounds, whereby substituted γ-lactones can easily be prepared in good to excellent yields under very mild conditions.Two mole equiv. of samarium(II) di-iodide to each mole equiv. of starting substrate always give reasonable yields.The presence of an alcohol is essential in the reaction, complex unidentified products being formed in the absence of an alcohol; t-butyl alcohol gave more satisfactory results than methanol and ethanol.The alcohol acts as a proton donor, the use of MeOD leading to a deuteriated γ-lactone.The reaction is applicable to both aliphatic and aromatic ketones or aldehydes, whereas the electrochemical method is limited to aliphatic substrates.The diastereoselectivity is examined in the reaction of 4-t-butylcyclo-hexanone with ethyl acrylate; an anti-isomer is produced predominantly (syn:anti = 1:9) as the result of selective axial attack.The reaction may proceed by a radical mechanism, and reaction may not involve a samarium ester homoenolate.The reaction is extended to the intramolecular reaction of an α,β-unsaturated keto ester (8-oxonon-2-enoate) leading to the ready synthesis of a bicyclic γ-lactone.
- Fukuzawa, Shin-ichi,Nakanishi, Akira,Fujinami, Tatsuo,Sakai, Shizuyoshi
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p. 1669 - 1676
(2007/10/02)
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- Amberlyst-A21 as a New and Efficient Surface Catalyst for the Conjugate Addition of Nitroalkanes to Methyl Acrylate: An Improved Synthesis of Methyl 4-Nitro- and 4-Oxoalkanoates
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Utilization of Amberlyst-A21 without solvent in the conjugate addition of nitroalkanes to methyl acrylate, affords 4-nitroalkanoic methyl esters in good yields.Successive Nef reaction, using potassium permanganate, provides functionalized 4-oxoalkanoic methyl esters.
- Ballini, Roberto,Petrini, Marino,Rosini, Goffredo
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p. 711 - 713
(2007/10/02)
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- Free Radical Addition of 2-Bromoalkanoic Acids to Alkenes
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The benzoyl peroxide-catalyzed reaction of 2-bromoalkanoic acids such as bromoacetic, 2-bromopropionic, and 2-bromobutyric acid with 1-alkenes was found to proceed thorough the addition of the C-Br bond across the double bond followed by cyclization affording 4-alkanolides in good yields.
- Nakano, Taichi,Kayama, Mikio,Nagai, Yoichiro
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p. 1049 - 1052
(2007/10/02)
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- Reductive Coupling of Ketones or Aldehydes with Electron-deficient Alkenes Promoted by Samarium Di-iodide
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Samarium di-iodide is an efficient reagent for the reductive coupling of ketones or aldehydes and electron-deficient alkenes, whereby γ-lactones can be prepared in good yields from ethyl acrylate.
- Fukuzawa, Shin-ichi,Nakanishi, Akira,Fujinami, Tatsuo,Sakai, Shizuyoshi
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p. 624 - 625
(2007/10/02)
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- STANNYL ESTER CYCLIZATIONS
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Alpha halo stannyl esters react with alkenes to afford lactones.The reaction is catalyzed by AIBN.The reaction proceeds best with electron rich alkenes.The mechanistic aspects of this novel reaction are discussed.This reaction can also be conducted intramolecularly to produce bicyclic lactones.An approach to the lignan system is presented.
- Kraus, George A.,Landgrebe, Kevin
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p. 4039 - 4046
(2007/10/02)
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- Electroorganic Chemistry. Part 73. Electroreductive Cross-coupling of 3-Substituted Alkanoic Acid Esters with Aldehydes or Acid Anhydrides
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Elecroreductive cross-coupling reaction of 3-phenylthioalkanoic acids esters (4a) or quaternary ammonium salts of 3-aminoalkanoic acid esters (4b) with aldehydes gave the corresponding γ-lactones in one step.The cross-coupling reaction of (4b) with acid anhydrides leading to the formation of the corresponding γ-keto esters is also described.
- Shono, Tatsuya,Matsumura, Yoshihiro,Kashimura, Shigenori
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p. 1922 - 1935
(2007/10/02)
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- Electroreductive hydrocoupling of activated olefins with ketones or aldehydes in the presence of trimethylchlorosilane
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Electroreductive crossed hydrocoupling of α,β-unsaturated esters with aldehydes or ketones in the presence of trimethylchlorosilane afforded γ-lactones in good yields. Similarly, α,β-unsaturated nitriles gave γ-hydroxynitriles in high yields.
- Shono, Tatsuya,Ohmizu, Hiroshi,Kawakami, Souta,Sugiyama, Hiroshi
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p. 5029 - 5032
(2007/10/02)
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