Enzymatic resolution of α-tetralols by CALB-catalyzed acetylation
摘要:
A series of homochiral alpha-tetralols, as well as their respective acetates, has been obtained by esterification of racemic tetralols, using Candida antarctica lipase (CALB-Novozym(R) 435) as the biocatalyst. This enzyme is shown to be highly efficient for the kinetic resolution of the substrates studied, affording the (+)-tetralols and the (+)-acetates in excellent enantiomeric excess (up to >99%) and very good yields (>40%). (C) 2007 Elsevier Ltd. All rights reserved.
Enzymatic resolution of α-tetralols by CALB-catalyzed acetylation
摘要:
A series of homochiral alpha-tetralols, as well as their respective acetates, has been obtained by esterification of racemic tetralols, using Candida antarctica lipase (CALB-Novozym(R) 435) as the biocatalyst. This enzyme is shown to be highly efficient for the kinetic resolution of the substrates studied, affording the (+)-tetralols and the (+)-acetates in excellent enantiomeric excess (up to >99%) and very good yields (>40%). (C) 2007 Elsevier Ltd. All rights reserved.
Design of Ru(II)-NHC-Diamine Precatalysts Directed by Ligand Cooperation: Applications and Mechanistic Investigations for Asymmetric Hydrogenation
作者:Wei Li、Tobias Wagener、Lars Hellmann、Constantin G. Daniliuc、Christian Mück-Lichtenfeld、Johannes Neugebauer、Frank Glorius
DOI:10.1021/jacs.0c00985
日期:2020.4.15
A modular synthesis of Ru(II)-NHC-diamine complexes from readily available chiral N-heterocyclic carbenes (NHCs) and chiraldiamines is disclosed for the first time. The well-defined Ru(II)-NHC-diamine complexes show unique structure and coordination chemistry including an unusual tridentate coordination effect of 1,2-diphenylethylenediamine. The isolated air- and moisture-stable Ru(II)-NHC-diamine
A set of 28 enantiomers comprising rigid and flexible secondary alcohols was synthesized by the asymmetric Corey-Bakshi-Shibata reduction. The enantiomerically pure alcohols were subjected to enzymatic glucuronidation assays employing the human UDP-glucuronosyltransferases (UGTs) 2B7 and 2BI7. Both UGTs displayed high levels of stereo selectivity, favoring the conjugation of the (R)-enantiomers over their respective (S)-stereoisomers at eudismic ratios up to 256. The spatial arrangement of the hydroxy group determined the diastereoselectivity of the UGT2B17-catalyzed reaction in agreement with Pfeiffer's rule (eudismic activity quotient = 0.83 +/- 0.14). Inhibition studies revealed that the enantiomers had similar affinities toward the enzymes. The diastereoselectivity of the UGT-catalyzed conjugation stemmed, therefore, from the arrangement of the substrates in the catalytic site, rather than from distinct affinities toward the enzymes. Taken together, this study showed that metabolic enzymes that are generally conceived to be rather "flexible" in nature are capable of displaying high levels of chiral distinction.
BINAP/1,4-Diamine−Ruthenium(II) Complexes for Efficient Asymmetric Hydrogenation of 1-Tetralones and Analogues
A combined system of a RuCl2(binap)(1,4-diamine) complex and t-C4H9OK in i-C3H7OH catalyzes enantioselective hydrogenation of various 1-tetralone derivatives and some methylated 2-cyclohexenones. Hydrogenation of 2-methyl-1-tetralone under dynamic kinetic resolution gives the cis alcohol with high ee.
Enzymatic resolution of α-tetralols by CALB-catalyzed acetylation
作者:Helena M.C. Ferraz、Graziela G. Bianco、Carla C. Teixeira、Leandro H. Andrade、André L.M. Porto
DOI:10.1016/j.tetasy.2007.05.007
日期:2007.5
A series of homochiral alpha-tetralols, as well as their respective acetates, has been obtained by esterification of racemic tetralols, using Candida antarctica lipase (CALB-Novozym(R) 435) as the biocatalyst. This enzyme is shown to be highly efficient for the kinetic resolution of the substrates studied, affording the (+)-tetralols and the (+)-acetates in excellent enantiomeric excess (up to >99%) and very good yields (>40%). (C) 2007 Elsevier Ltd. All rights reserved.