摘要:
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.