Abstract: gem-(Difluoroally1) lithium may be generated by lithium-bromine exchange between n-butyllithium and CH2= CHCF2Br at-95 “C by using an in situ procedure. When this Li [CF2CHCH2] preparation is carried out in the presence of chlorosilanes, aldehydes, ketones, and esters, products of the type R 3 S i CF 2 CH 4 H 2, RCH (OH) CF2CH== CH2, and RR'C (OH) CF2CH= CH2, respectively, are formed, often in good yield. The factors ...