Flash generation and borylation of 1-(trifluoromethyl)vinyllithium toward synthesis of alpha-(trifluoromethyl)styrenes

Thermally unstable (3,3,3-trifluoroprop-1-en-2-yl)lithium was generated by lithiation of 2-bromo-3,3,3-tri-fluoroprop-1-ene and successively underwent borylation in a flow microreactor system. Direct use of the 1-(trifluoromethyl)vinylborate thus formed for the Suzuki-Miyaura coupling in a batch system afforded alpha-(tri-fluoromethyl)styrenes in high yields.