From C₁ to C₃: Copper‐Catalyzed <i>gem</i>‐Bis(trifluoromethyl)olefination of α‐Diazo Esters with TMSCF₃

Abstract

Abstract A Cu‐catalyzed gem ‐bis(trifluoromethyl)olefination of α‐diazo esters, using TMSCF 3 as the only fluorocarbon source, has been developed and provides an exquisite method to access gem ‐bis(trifluoromethyl)alkenes. This unprecedented olefination process involves a carbene migratory insertion into “CuCF 3 ” to generate the α‐CF 3 ‐substituted organocopper species, which then undergoes β‐fluoride elimination and two consecutive addition‐elimination processes to give the desired products. The key to this efficient one‐pot C 1 ‐to‐C 3 synthetic protocol lies in the controllable double (over single and triple) trifluoromethylations of the gem‐ difluoroalkene intermediates.