Asymmetric Catalytic Synthesis of α-Aryloxy Alcohols: Kinetic Resolution of Terminal Epoxides via Highly Enantioselective Ring-Opening with Phenols
作者:Joseph M. Ready、Eric N. Jacobsen
DOI:10.1021/ja9910917
日期:1999.6.1
terminal epoxides with catalyst 3b4 (Scheme 1, Nu ) OH) suggested that (salen)Co(III) complexes might also serve as effective catalysts for the enantioselective addition of phenols to epoxides. This strategy has proven successful, and we report here the first examples of kinetic resolution of epoxides with phenols, with the isolation of 1-aryloxy 2-alcohols (1) in high ee’s and yields. Reaction of 2.2
Jacobsen’s cobalt-salen complex was covalently immobilized on polymer carriers that are part of different technical setups (polymer powder, composite Raschig rings, PASSflow microreactors) and employed for the enantioselective ring opening of terminal epoxides with water and phenols. The polymer-supported catalysts showed good activity and stereoselectivity and could be used repeatedly after a simple reactivation protocol in both batch as well as continuous-flow modes.
Highly active oligomeric Co(salen) catalysts for the asymmetric synthesis of α-aryloxy or α-alkoxy alcohols via kinetic resolution of terminal epoxides
作者:Xunjin Zhu、Krishnan Venkatasubbaiah、Marcus Weck、Christopher W. Jones
DOI:10.1016/j.molcata.2010.06.015
日期:2010.8.17
alcohols. The catalyst is compared to other dimeric, oligomeric and monomeric Co(salen) complexes including a pimelate-linked macrocyclic Co(salen) catalyst and a dimeric Co(salen) catalyst referred to as a bisalen. The catalysts that contain multiple Co(salen) units within a single molecular framework allow for substantial decreases in catalyst loading compared with the monomeric catalyst. The cyclooctene-based
[EN] STEREOSELECTIVE RING OPENING REACTIONS<br/>[FR] REACTIONS STEREOSELECTIVES D'OUVERTURE DE CYCLE
申请人:HARVARD COLLEGE
公开号:WO2000009463A1
公开(公告)日:2000-02-24
The present invention relates to a process for stereoselective or regioselective chemical synthesis which generally comprises reacting a nucleophile, selected from the group consisting of water, alcohols, carboxylic acids, and thiols, and a racemic or diastereomeric mixture of a cyclic substrate in the presence of a non-racemic, chiral catalyst to effect a kinetic resolution of the cyclic substrate. The present invention also relates to hydrolytic kinetic resolutions of racemic and diastereomeric mixtures of epoxides.