Synthesis of C-glycosyl amino acids: scope and limitations of the tandem Tebbe/Claisen approach
作者:David J. Chambers、Graham R. Evans、Antony J. Fairbanks
DOI:10.1016/j.tetasy.2004.11.035
日期:2005.1
as substrates for the tandem Tebbe/Claisenapproach to the synthesis of C-glycosyl amino acids. Whilst esters of substituted α-amino acids do not successfully undergo Tebbe, or other, methylenation, esters of β- or γ-amino acids are methylenated to yield vinyl ethers, which then undergo smooth thermal rearrangement to yield β-C-glycoside products. tert-Butyl esters are found to be unreactive to the
Synthesis of α-C-glycosides via tandem Tebbe methylenation and Claisen rearrangement
作者:H.Yasmin Godage、Antony J. Fairbanks
DOI:10.1016/s0040-4039(03)00710-x
日期:2003.4
A variety of alpha-C-glycosides may be accessed in an entirely stercoselective fashion from 3-OH glycal esters, by way of the tandem reaction sequence of Tebbe methylenation and Claisen rearrangement. In contrast with previous studies in the corresponding beta-series, careful control of conditions for Claisen rearrangement is required in order to avoid loss of integrity of anomeric stereochemistry; thermal rearrangements are best carried out in xylene in a sealed tube. (C) 2003 Elsevier Science Ltd. All rights reserved.