Syn-SN2' pathway in the reaction of certain .gamma.-(mesyloxy) .alpha.,.beta.-enoates with RCu(CN)MgX.BF3 reagents. Importance of MgX and bulky R group upon the diastereoselectivity
作者:Toshiro Ibuka、Tooru Taga、Hiromu Habashita、Kazuo Nakai、Hirokazu Tamamura、Nobutaka Fujii、Yukiyasu Chounan、Hisao Nemoto、Yoshinori Yamamoto
DOI:10.1021/jo00057a038
日期:1993.2
The reactions of protected serine- and threonine-derived gamma-(mesyloxy) alpha,beta-unsaturated esters with various magnesio organocyanocopper Lewis acid complexes have been investigated. The formation of syn-S(N)2' products, in addition to the normally expected anti-S(N)2' products, is taken as an indication that the reaction proceeds by a mechanism involving coordination of the magnesiocuprate with the C(delta)-N:C(gamma)-O syn-gamma-(mesyloxy) alpha,beta-enoates.