The general approach for the synthesis of substituted cyclobutenyl- and norbornadienyllithiums containing masked trifluoromethyl group

α,β-Unsaturated trifluoromethylketones of cyclobutene number containing trimethylstannyl substituent in β-position were firstly prepared by the addition of trimethylstannyllithium to the corresponding trifluoromethylenaminoketones. The protection of carbonyl function under basic conditions conserving the organometallic substituent was elaborated. The generation of corresponding organolithiums by Sn–Li exchange and their reactivity was studied.