COUNTERION INFLUENCE ON THE STEREOCHEMISTRY OF CYCLOPROPANE FORMATION VIA ORGANOCOPPER AND ORGANOSODIUM INTERMEDIATES

Cyclopropanes are formed from methyl α-chloro-propionate and methacrylonitrile using ButOCu·PBu3n or NaH, via organocopper or organosodium intermediates; a counterion effect on the cis/trans stereo-chemistry of cyclopropane formation is observed.