Temperature-dependent isomerisation versus net fragmentation of secondary allylic alcohols with Grubbs’ catalyst
摘要:
Secondary allylic alcohols with 10 mol% of Grubbs catalyst in refluxing toluene/1,2-dichloroethane undergo isomerisation to ethyl ketones whereas with 100 mol% of Grubbs catalyst at room temperature, a net fragmentation reaction with the loss of a carbon atom occurs, to provide a methyl ketone. Probable mechanisms are described. (C) 2001 Elsevier Science Ltd. All rights reserved.
A Convenient and Versatile Method for the Preparation of α-Hydroxymethyl Ketone Derivatives from the Corresponding Allyl Silyl Ethers or Allyl Carboxylates
作者:Yung-Son Hon、Ying-Chieh Wong、Kuo-Jui Wu
DOI:10.1002/jccs.200800134
日期:2008.8
The ozonolysis of 1-substituted allyl silyl ethers or 1-substituted allyl carboxylates followed by treatment with bases gave the corresponding α-silyloxymethyl- or a-acyloxymethyl-ketones in good yields. It is proposed to proceed via the corresponding α-silyloxy- or α-acyloxyaldehydes intermediates followed by 1,4-group migration. The results of theoretical calculations are applicable to explain the