133098-13-2Relevant academic research and scientific papers
Novel anti-Prelog stereospecific carbonyl reductases from Candida parapsilosis for asymmetric reduction of prochiral ketones
Nie, Yao,Xiao, Rong,Xu, Yan,Montelione, Gaetano T.
, p. 4070 - 4078 (2011)
The application of biocatalysis to the synthesis of chiral molecules is one of the greenest technologies for the replacement of chemical routes due to its environmentally benign reaction conditions and unparalleled chemo-, regio- and stereoselectivities. We have been interested in searching for carbonyl reductase enzymes and assessing their substrate specificity and stereoselectivity. We now report a gene cluster identified in Candida parapsilosis that consists of four open reading frames including three putative stereospecific carbonyl reductases (scr1, scr2, and scr3) and an alcohol dehydrogenase (cpadh). These newly identified three stereospecific carbonyl reductases (SCRs) showed high catalytic activities for producing (S)-1-phenyl-1,2-ethanediol from 2-hydroxyacetophenone with NADPH as the coenzyme. Together with CPADH, all four enzymes from this cluster are carbonyl reductases with novel anti-Prelog stereoselectivity. SCR1 and SCR3 exhibited distinct specificities to acetophenone derivatives and chloro-substituted 2-hydroxyacetophenones, and especially very high activities towards ethyl 4-chloro-3-oxobutyrate, a β-ketoester with important pharmaceutical potential. Our study also showed that genomic mining is a powerful tool for the discovery of new enzymes.
Elucidation of the Stereospecificity of C-Methyltransferases from trans-AT Polyketide Synthases
Xie, Xinqiang,Khosla, Chaitan,Cane, David E.
, p. 6102 - 6105 (2017)
S-Adenosyl methionine (SAM)-dependent C-methyltransferases are responsible for the C2-methylation of 3-ketoacyl-acyl carrier protein (ACP) intermediates to give the corresponding 2-methy-3-ketoacyl-ACP products during bacterial polyketide biosynthesis mediated by trans-AT polyketide synthases that lack integrated acyl transferase (AT) domains. A coupled ketoreductase (KR) assay was used to assign the stereochemistry of the C-methyltransferase-catalyzed reaction. Samples of chemoenzymatically generated 3-ketopentanoyl-ACP (9) were incubated with SAM and BonMT2 from module 2 of the bongkrekic acid polyketide synthase. The resulting 2-methyl-3-ketopentanoyl-ACP (10) was incubated separately with five (2R)- or (2S)-methyl specific KR domains. Analysis of the derived 2-methyl-3-hydroxypentanoate methyl esters (8) by chiral GC-MS established that the BonMT2-catalyzed methylation generated exclusively (2R)-2-methyl-3-ketopentanoyl-ACP ((2R)-10). Identical results were also obtained with three additional C-methyltransferases-BaeMT9, DifMT1, and MupMT1-from the bacillaene, difficidin, and mupirocin trans-AT polyketide synthases
Practical asymmetric hydrogenation of β-keto esters at atmospheric pressure using chiral Ru (II) catalysts
Genet
, p. 4801 - 4804 (1995)
New practical conditions of asymmetric hydrogenation of β-keto esters with chiral Ru(II) catalysts are described. It is now possible to carry out the reaction at atmospheric pressure. Under these conditions, β-keto esters are hydrogenated to β-hydroxy esters with excellent enantiomeric excesses (up to 99%) using chiral ruthenium (II) catalysts easily prepared in situ by treatment of commercially available (COD)Ru(2-methylallyl)2 in the presence of the appropriate chiral ligands such as Binap, MeO-Biphep and Me-Duphos.
Asymmetric hydrogenation of β-keto esters using chiral diphosphonites
Reetz, Manfred T.,Li, Xiaoguang
, p. 1157 - 1160 (2006)
The BINOL-derived diphosphonite having an achiral backbone based on diphenyl ether is a readily accessible and cheap ligand for the enantioselective Ru-catalyzed hydrogenation of β-keto esters (ee = 95-99%).
Ruthenium complexes of phosphine-aminophosphine ligands
Boaz, Neil W.,Ponasik Jr., James A.,Large, Shannon E.
, p. 4033 - 4035 (2006)
Ruthenium complexes of phosphinoferrocenylaminophosphine ligands (BoPhoz ligands) have been prepared by combining the ligands with tris(triphenylphosphine)ruthenium dichloride and precipitating the complexes. The optimal species exhibit high enantioselectivities for the asymmetric hydrogenation of functionalized ketones, particularly β-ketoesters.
'Diam-BINAP'; a highly efficient monomer for the synthesis of heterogeneous enantioselective catalysts
Ter Halle, Rob,Colasson, Benoist,Schulz, Emmanuelle,Spagnol, Michel,Lemaire, Marc
, p. 643 - 646 (2000)
The synthesis of a monomeric analogue of BINAP, diam-BINAP, is described. The polyaddition of this monomer with 2,6-diisocyanato toluene gave the corresponding oligomer, poly-NAP, with a polymerization degree of 8. The ruthenium complex of this polymer proved to be a very efficient heterogeneous catalyst for the hydrogenation of β-ketoesters (99% ee, 0.1 mol% of catalyst). Furthermore the catalyst could be easily reused four times by simple filtration without loss of activity or enantioselectivity. (C) 2000 Elsevier Science Ltd.
Asymmetric hydrogenation by RuCl2(R-Binap)(dmf)n encapsulated in silica-based nanoreactors
Peng, Juan,Wang, Xuefeng,Zhang, Xiaoming,Bai, Shiyang,Zhao, Yaopeng,Li, Can,Yang, Qihua
, p. 666 - 672 (2015)
The Noyori catalyst RuCl2(R-Binap)(dmf)n has been successfully encapsulated in C-FDU-12 by using the active chlorosilane Ph2Cl2Si as the silylating agent. 31P-NMR results show that there is no strong interaction between the molecular catalyst and the solid support, thus the encapsulated molecular catalyst could move freely in the nanoreactor during the catalytic process. The solid catalyst exhibits high activity and enantioselectivity for the asymmetric hydrogenation of a series of β-keto esters due to the preserved intrinsic properties of RuCl2(R-Binap)(dmf)n encapsulated in the nanoreactor. The solid catalyst could be recycled by simple filtration and be reused at least four times.
A substrate specific chiral modifier activation on enantio-differentiating hydrogenation over tartaric acid-modified raney nickel
Nakagawa, Satoshi,Sugimura, Takashi,Tai, Akira
, p. 1257 - 1258 (1998)
A comparative study of the reactivities of the hydrogenation of β-ketoesters over tartaric acid-modified and unmodified Raney nickels indicated that a substrate specific activation by the tartaric acid modification is the reason for the almost perfect enantio-differentiation in the reaction of methyl 3-cyclopropyl-3-oxopropanoate (4).
STEREOCHEMICAL INVESTIGATION ON ASYMMETRICALLY MODIFIED RANEY NICKEL CATALYST. MODE OF INTERACTION BETWEEN MODIFYING REAGENT AND SUBSTRATE IN THE ENANTIOFACE-DIFFERENTIATING PROCESS.
Tai,Harada,Hiraki,Murakami
, p. 1414 - 1419 (1983)
This paper considers details on the mode of enantioface-differentiation process and the validity of a proposed sterochemical model, based on the following two series of investigations: 1) The hydrogenation of methyl acetoacetate over Raney nickel modified with NaBr and a compound whose structure is analogous to tartaric acid, and 2) the hydrogenation of various prochiral ketones over tartaric acid-NaBr- modified Raney nickel.
Stereodiverse Iterative Synthesis of 1,3-Polyol Arrays through Asymmetric Catalytic Hydrogenation. Formal Total Synthesis of (-)-Cyanolide A
Che, Wen,Li, Yu-Zhen,Liu, Jin-Chi,Zhu, Shou-Fei,Xie, Jian-Hua,Zhou, Qi-Lin
, p. 2369 - 2373 (2019)
An iterative protocol was developed for highly diastereo- and enantioselective construction of high-order 1,3-polyols via iridium-catalyzed asymmetric hydrogenation of β-alkyl-β-keto esters. The protocol involves four operations - asymmetric hydrogenation, hydroxy protection, ester hydrolysis, and C-acylation - and the catalyst loading can be as low as 0.005 mol %. The configurations of all stereogenic centers of 1,3-polyols are controlled by the catalyst. By the use of this protocol, a formal total synthesis of the polyketide cyanolide A was achieved with high diastereoselectivity and enantioselectivity.
