109053-86-3Relevant academic research and scientific papers
Efficient enantioselective synthesis of methyl esters of α-unsubstituted β-hydroxy acids via asymmetric aldol-type addition of chiral boron enolates of (methylthio)acetic acid to aldehydes
Fringuelli, Francesco,Piermatti, Oriana,Pizzo, Ferdinando
, p. 1207 - 1211 (1996)
The aldol-type addition of chiral boron enolates of (methylthio)acetic acid to various aldehydes gives α-(methylthio)-β-hydroxy acids stereoselectively and with good yields. The desulfenylation of methyl esters of the condensation adducts allows methyl es
Total synthesis of amphidinolide T3 using ring-closing metathesis and asymmetric dihydroxylation strategy
Wu, Dongdong,Li, Huoming,Jin, Jian,Wu, Jinlong,Dai, Wei-Min
, p. 895 - 898 (2011)
Total synthesis of amphidinolide T3, a 19-membered ring marine macrolide, has been accomplished using a ring-closing metathesis (RCM) and asymmetric dihydroxylation (AD) strategy. A cycloalkene having the C12=C13 double bond was assembled via RCM in 80% yield and in E/Z ratio of 76:24. The (12E)-isomer -underwent AD using 1 mol% K2OsO2(OH)4 and 4 mol% (DHQD)2AQN as the chiral catalyst at 0 C for 15 hours, furnishing the desired (12R,13R)-diol and its (12S,13S)-diastereomer in 59% and 25% yields, respectively. Selective monosilylation of (12R,13R)-diol followed by DMP oxidation and desilylation afforded amphidinolide T3 in 3.4% overall yield via a 15-step sequence. Georg Thieme Verlag Stuttgart · New York.
Over 98% optical yield achieved by a heterogeneous catalysis. Substrate design and analysis of enantio-differentiating factors of tartaric acid-modified Raney nickel hydrogenation
Sugimura, Takashi,Nakagawa, Satoshi,Tai, Akira
, p. 355 - 363 (2002)
Tartaric acid-modified Raney nickel (TA-MRNi) is a chiral heterogeneous catalyst for the hydrogenation of prochiral ketones. An optical yield (OY) of 86% with methyl acetoacetate (1) as a substrate was improved to 94-96% by employing β-keto esters having a proper bulkiness at the γ-position. The γ-bulkiness effect contributes to a high intrinsic enantio-differentiating ability (factor-i) of the TA-MRNi catalysis. Through the study, we found the best substrate, γ-cyclopropyl-β-keto ester, the hydrogenation of which resulted in 98.6% OY. This further improvement in the OY was ascribed to a smaller contribution of non-enantio-differentiating hydrogenation (N-site catalysis) due to the substrate-specific activation of the enantio-differentiating hydrogenation by the chiral modifier. The OY of the hydrogenation of 1 was analyzed by comparing with well-behaved β-keto esters, and the contribution of the factor-i and the N-site to the OY value was evaluated to deduce the origin of the enantiodifferentiation.
Chiral Surfactant-Type Catalyst: Enantioselective Reduction of Long-Chain Aliphatic Ketoesters in Water
Lin, Zechao,Li, Jiahong,Huang, Qingfei,Huang, Qiuya,Wang, Qiwei,Tang, Lei,Gong, Deying,Yang, Jun,Zhu, Jin,Deng, Jingen
, p. 4419 - 4429 (2015/05/13)
A series of amphiphilic ligands were designed and synthesized. The rhodium complexes with the ligands were applied to the asymmetric transfer hydrogenation of broad range of long-chained aliphatic ketoesters in neat water. Quantitative conversion and excellent enantioselectivity (up to 99% ee) was observed for α-, β-, γ-, δ- and ε-ketoesters as well as for α- and β-acyloxyketone using chiral surfactant-type catalyst 2. The CH/π interaction and the strong hydrophobic interaction of long aliphatic chains between the catalyst and the substrate in the metallomicelle core played a key role in the catalytic transition state. Synergistic effects between the metal-catalyzed site and the hydrophobic microenvironment of the core in the micelle contributed to high stereoselectivity. (Chemical Equation Presented).
Development of Chiral Spiro P-N-S Ligands for Iridium-Catalyzed Asymmetric Hydrogenation of β-Alkyl-β-Ketoesters
Bao, Deng-Hui,Wu, Hui-Ling,Liu, Chao-Lun,Xie, Jian-Hua,Zhou, Qi-Lin
supporting information, p. 8791 - 8794 (2015/11/27)
The chiral tridentate spiro P-N-S ligands (SpiroSAP) were developed, and their iridium complexes were prepared. Introduction of a 1,3-dithiane moiety into the ligand resulted in a highly efficient chiral iridium catalyst for asymmetric hydrogenation of β-alkyl-β-ketoesters, producing chiral β-alkyl-β-hydroxyesters with excellent enantioselectivities (95-99.9 % ee) and turnover numbers of up to 355 000. Bulkyness is the key: New chiral tridentate spiro P-N-S ligands (SpiroSAP) bearing a conformationally constrained 1,3-dithiane moiety were developed. Their iridium catalysts showed excellent enantioselectivities and activity (TON up to 355 000) for asymmetric hydrogenation of β-alkyl-β-ketoesters.
Enzymatic total synthesis of banana volatile (S)-2-pentyl (R)-3-hydroxyhexanoate
Kallergi, Maria,Kalaitzakis, Dimitris,Smonou, Ioulia
experimental part, p. 3946 - 3950 (2011/09/14)
The banana volatile (S)-2-pentyl (R)-3-hydroxyhexanoate has been synthesized in 79 % yield and high optical purity (>99 % ee, >99 % de) starting from methyl 3-oxohexanoate and 2-pentanone. The synthetic method consists of three steps and the key reactions are enzymatic reduction and enzymatic transesterification. Copyright
Organocatalytic preparation of simple β-hydroxy and β-amino esters: Low catalyst loadings and gram-scale synthesis
Jiang, Hao,Gschwend, Bjoern,Albrecht, Lukasz,Anker Jorgensen, Karl
supporting information; experimental part, p. 5052 - 5055 (2010/12/25)
A combined amino- and N-heterocyclic carbene (NHC)-catalyzed one-pot reaction sequence for the synthesis of simple enantioenriched β-hydroxy and β-amino esters using commercially available catalysts at low catalyst loadings has been developed. The desired
Lipase-promoted asymmetric transesterification of 4-alkyloxetan-2-ones with ring-opening
Koichi, Yota,Suginaka, Kaoru,Yamamoto, Yukio
, p. 1645 - 1646 (2007/10/02)
Lipase-catalysed reaction of (+/-)-4-alkyloxetan-2-ones 1a-c with benzyl alcohol gave (R)-1a (R=Me) (36percent, 96percent ee) and benzyl (S)-3-hydroxybutanoate 2a (51percent, 85percent ee), (R)-1b (R=Pr) (42percent, 75percent ee) and benzyl (S)-3-hydroxyhexanoate 2b (45percent, 69percent ee) and (S)-1c (R=Pr-i, 41percent, 95percent ee) and benzyl (R)-3-hydroxy-4-methylpentanoate 2c (43percent, 90percent ee), respectively.
Asymmetric Reduction of Aliphatic Short- to Long-Chain β-Keto Acids by Use of Fermenting Bakers' Yeast
Utaka, Masanori,Watabu, Hisashi,Higashi, Hiroshi,Sakai, Takashi,Tsuboi, Sadao,Torii, Sigeru
, p. 3917 - 3921 (2007/10/02)
Eleven β-keto acids, ranging from 3-oxobutanoic to 3-oxooctanoic acids, were reduced with fermenting bakers' yeast to the corresponding optically active β-hydroxy acids, which were isolated as the methyl esters.In all cases, the (R)-hydroxy acids were obtained in >/=98percent ee, except for 3-oxobutanoic acid, which afforded the (S)-hydroxy acid in 86percent ee.Inhibition of fermentation was observed for 3-oxoundecanoic to 3-oxotetradecanoic acids, leading to no reduction.Lowering of the substrate concentration was found to be appreciably effective in avoiding inhibition.
Preparation of Enantiomerically Pure β-Silylcarboxyl Derivatives by Asymmetric 1,4-Addition to N-Enoyl-sultams
Oppolzer, Wolfgang,Mills, Robert J.,Pachinger, Werner,Stevenson, Thomas
, p. 1542 - 1545 (2007/10/02)
EtAlCl2-promoted additions of organocopper reagents to camphor-derived, conjugated N-enoyl-sultams gave saturated and olefinic β-silylcarboxyl derivatives with high diastereodifferentiation.Nondestructive removal of the chiral auxiliary followed by oxidative Si-C bond cleavage furnished enantiomerically pure acetate-derived aldols and propionate-derived 'anti'-aldols (via silyl-directed α-methylation).
