Asymmetric Synthesis of the Tricyclic Core of <i>Calyciphylline</i> A-Type Alkaloids via Intramolecular [3 + 2] Cycloaddition
作者:Lu Wang、Chen Xu、Li Chen、Xiaojiang Hao、David Zhigang Wang
DOI:10.1021/ol403609c
日期:2014.2.21
Asymmetric synthesis of the [5–6–7] tricyclic system common to the Calyciphylline A-type alkaloids is reported, featuring Overman rearrangement, Heckcyclization, intramolecular [3 + 2] cycloaddition, diastereoselective hydrogenation, and Claisen rearrangement as strategic events. The approach is capable of installing the crucial carbonyl functionality as well as multiple stereogenic centers within
A range of cyclic allylic trichloroacetamides has been synthesised. Dihydroxylation utilising catalytic osmium tetroxide and quinuclidine-N-oxide monohydrate as the re-oxidant in dichloromethane yields diols with good levels of syn selectivity. (C) 2000 Elsevier Science Ltd. All rights reserved.