Photoredox Enabled Defluorinative Benzylation of Trifluoromethyl Alkenes with Alkylarenes

Abstract

Herein, we report a photoredox enabled defluorinative benzylation of trifluoromethyl alkenes with readily available alkylarenes, which provides convenient access to a series of structurally valuable benzylated gem-difluoroalkenes under mild reaction conditions. The synthetic value of this protocol has been demonstrated by the transformations of several substrates bearing drug moieties, gram-scale reactions, and various further derivatizations of the gem-difluoroalkene products. The preliminary mechanistic investigations suggest a reaction pathway with rate-determining benzyl C−H bond cleavage of toluene followed by benzylic radical formation.

Visible Light‐Mediated Defluorination to Access 1,1‐Difluoro‐1,3‐Enynes

“…[11][12] For example, the addition of the radicals produced from diverse precursors to alkenes containing CF 3 , followed by the β-F elimination is one of the efficient methods. [13][14][15][16][17][18][19][20][21][22][23][24] However, the scope of alkenes was mainly concentrated on aryl alkenes.…”

Visible-light-induced hydroxycarboxylation of α-trifluoromethylstyrenes to construct densely functionalized α-CF3 tertiary alcohols

“…7 d ,8 In addition, α-trifluoromethylstyrenes have always been important structural units 9 and are widely used to synthesize various fluorinated compounds with diverse structures. In the past few years, many transformations of α-trifluoromethylstyrenes have been developed, such as alkylation, 10 arylation, 11 benzylation, 12 ammonification 13 gem -difluoroalkylation, 14 etc. (Scheme 1d).…”