‘Transmitted’ remote double diastereoselection effects on the asymmetric reduction of β-boronate oxime ethers
作者:Helen E. Sailes、John P. Watts、Andrew Whiting
DOI:10.1016/s0040-4039(00)00179-9
日期:2000.4
Remote asymmetric induction in the reduction of a homochiral beta-boronate oxime ether to the corresponding amine failed to provide asymmetric induction with achiral reducing agents, but use of a chiral reducing agent produced extreme double diastereoselection effects which show that remote asymmetry can be 'transmitted' by suitable choice of a 'partner' molecule. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.
Studies on the asymmetric reduction of β-oximino methyl ether boronates: reagent control, double diastereocontrol and transmitted remote asymmetric induction
作者:Helen E. Sailes、John P. Watts、Andrew Whiting
DOI:10.1039/b005837h
日期:——
Highasymmetricinduction (94% ee) could be obtained in the reduction of the achiral E-oxime ether boronate 5 with a homochiral oxazaborolidine 13–BH3–THF complex. Application of this homochiral reducing agent system to non-aromatic oxime ethers 21 produced low to moderate asymmetricinduction. Application of the same homochiral reducing agent system to reduction of homochiral boronate E-oximes 3 and
Synthesis, structure and comparative stability of β-hydrazono, oximino methyl ether and imino boronates
作者:Richard J. Mears、Helen E. Sailes、John P. Watts、Andrew Whiting
DOI:10.1039/b004573j
日期:——
prepared by the sequential lithiation of the corresponding methyl hydrazone or oxime methyl ether, followed by reaction with an iodomethylboronate ester, typically in the form of the pinacol ester. The resulting products have contrasting hydrolytic stabilities. β-Hydrazono boronates are highly sensitive to intramolecularly catalysed hydrolysis, providing the corresponding β-keto boronates in generally high