An Unexpected Directing Effect in the Asymmetric Transfer Hydrogenation of α,α-Disubstituted Ketones
摘要:
alpha,alpha-Disubstituted ketones containing an aromatic ring or alkene are reduced in high enantiomeric excess using an asymmetric transfer hydrogenation catalyst. The sense of reduction indicates that the unsaturated region of the ketone adopts a position adjacent to the Ru-bound eta(6)-arene ring in the reduction transition state.
An Unexpected Directing Effect in the Asymmetric Transfer Hydrogenation of α,α-Disubstituted Ketones
作者:Rina Soni、John-Michael Collinson、Guy C. Clarkson、Martin Wills
DOI:10.1021/ol201643v
日期:2011.8.19
alpha,alpha-Disubstituted ketones containing an aromatic ring or alkene are reduced in high enantiomeric excess using an asymmetric transfer hydrogenation catalyst. The sense of reduction indicates that the unsaturated region of the ketone adopts a position adjacent to the Ru-bound eta(6)-arene ring in the reduction transition state.
Kinetic Resolution of Neopentylic Secondary Alcohols by Cu–H-Catalyzed Enantioselective Silylation with Hydrosilanes
作者:Zaneta Papadopulu、Martin Oestreich
DOI:10.1021/acs.orglett.0c03943
日期:2021.1.15
A nonenzymatic kineticresolution of sterically congested alcohols having a quaternary carbon atom in the β-position is reported. The catalyst system CuCl/NaOtBu/(R,R)-Ph-BPE together with a 3,5-xylyl-substituted tertiary hydrosilane enable enantioselective silylation of the hydroxy group. Several alcohols are obtained with good to excellent selectivity factors, and there are no other known straightforward
报道了在β位具有季碳原子的空间拥挤的醇的非酶动力学拆分。催化剂体系CuCl / NaO t Bu /(R,R)-Ph-BPE与3,5-二甲苯基取代的叔氢硅烷一起使羟基的对映选择性硅烷化成为可能。获得了具有良好至优异的选择性因子的几种醇,并且没有其他已知的直接方法可访问这些基序。