Enantioselective acylation of primary and secondary alcohols catalyzed by lipase QL from Alcaligenes sp.: A predictive active site model for lipase QL to identify which enantiomer of an alcohol reacts faster in this acylation
摘要:
Lipase QL (from Alcaligenes sp.)-catalyzed acylation of alcohols using isopropenyl acetate as the acylating agent in diisopropyl ether converted preferentially primary alcohols with an S configuration and secondary alcohols with an R configuration into the corresponding homochiral acetates. On the basis of observed enantiomer selectivities, a predictive active site model for lipase QL is proposed for identifying which enantiomer of a primary or a secondary alcohol reacts faster in this acylation. Copyright (C) 1996 Published by Elsevier Science Ltd
Pentaphenylcyclopentadienyl ruthenium complexes (3) are excellent catalysts for the racemization of secondary alcohols at ambient temperature. The combination of this process with enzymatic resolution of the alcohols results in a highly efficient synthesis of enantiomericallypure acetates at room temperature with short reaction times for most substrates. This new reaction was applied to a wide range
<b>PQXdpap</b>: Helical Poly(quinoxaline-2,3-diyl)s Bearing 4-(Dipropylamino)pyridin-3-yl Pendants as Chirality-Switchable Nucleophilic Catalysts for the Kinetic Resolution of Secondary Alcohols
Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-(dipropylamino)pyridin-3-yl pendants at the 5-position of the quinoxaline ring (PQXdpap) exhibited high catalytic activities and moderate to high selectivities (up to s = 87) in the acylative kinetic resolution of secondary alcohols. The solvent-dependent helical chirality switching of PQXdpap between pure toluene and a 1:1 mixture of toluene and
A general and practical process for the conversion of prochiral ketones into the corresponding chiral acetates has been realized. An iron carbonyl complex is reported to catalyze the hydrogenation–dehydrogenation–hydrogenation of prochiral ketones. By merging the iron‐catalyzed redox reactions with enantioselective enzymatic acylations a wide range of benzylic, aliphatic and (hetero)aromatic ketones
Dynamic Kinetic Resolution of a Wide Range of Secondary Alcohols: Cooperation of Dicarbonylchlorido(pentabenzylcyclopentadienyl)ruthenium and CAL-B
作者:Mari Päiviö、Denys Mavrynsky、Reko Leino、Liisa T. Kanerva
DOI:10.1002/ejoc.201001703
日期:2011.3
The substrate scope in the dynamickineticresolution of secondary alcohols was studied by using 31 structurally different alcohols and isopropenyl acetate in the presence of dicarbonylchlorido(pentabenzylcyclopentadienyl)ruthenium and Candida antarctica lipase B (Novozym435, CAL-B) in toluene. The enzyme and the rutheniumcomplex were shown to function in a highly compatible manner allowing the conversion
A Cationic Ruthenium Complex for the Dynamic Kinetic Resolution of Secondary Alcohols
作者:José A. Fernández-Salas、Simone Manzini、Steven P. Nolan
DOI:10.1002/chem.201404096
日期:2014.10.6
A synthetic protocol making use of a well‐defined cationic ruthenium complex 2 enabling the racemization of enantiomerically pure secondary alcohols in the presence of a weak base (K2CO3) is described. The compatibility of 2 with Candida Antarctica lipase B (Novozym 435) allows the development of an efficient dynamic kinetic resolution of sec‐alcohols in the absence of an additional strong base. This
描述了利用定义明确的阳离子钌络合物2的合成方案,该阳离子络合物可使对映体纯的仲醇在弱碱(K 2 CO 3)存在下外消旋。2与南极假丝酵母脂肪酶B(Novozym 435)的相容性可在不存在其他强碱的情况下,开发出仲醇的有效动态动力学拆分方法。该方法涉及在阳离子钌催化剂存在下醇的动态动力学拆分的第一个实例。此外,我们描述了单锅反应中酮向富含对映体的乙酸酯的转化,探讨了复合物2的多功能性。