Synthesis of chiral vinylic sulfoxides by Pd-catalyzed asymmetric sulfinylzincation
作者:Naoyoshi Maezaki、Suguru Yagi、Shizuka Ohsawa、Hirofumi Ohishi、Tetsuaki Tanaka
DOI:10.1016/j.tet.2003.10.037
日期:2003.12
Novel asymmetric sulfinylzincation of alkynoates has been accomplished via a Pd-catalyzed sulfinylzincation using 1-alkynyl sulfoxides bearing chiral auxiliaries as a sulfinylating reagent. The reaction proceeded in a highly syn-selective fashion, giving the (E)-beta-sulfinyl alpha,beta-unsaturated ester exclusively. Among the chiral sulfinylating reagents tested, an isoborneol-type compound (Rs)-4 showed the best results in terms of both yield and diastereoselectivity. As a result of optimization of the reaction, the selectivity was improved up to 92:8 dr, and stereochemistry of the newly formed sulfur stereogenic center was revealed as (Ss)-configuration. (C) 2003 Elsevier Ltd. All rights reserved.