Difluorocarbene, a versatile bipolar intermediate, has been widely exploited in ionic-type coupling reactions. Its direct transformation into a fluorinated carbon-radical species, however, has remained a formidable challenge because of the large singlet-triplet energy gap. Here we report an unprecedented strategy that unlocks difluorocarbene as a precursor for both fluorinated carbanions and carbon radicals through the thermolytic homolysis of an aryldifluoromethylpalladium intermediate. This palladium-catalyzed sequential process enables a modular three-component coupling of aryl iodides, alkenes, and ClCF 2 H, delivering a broad spectrum of difluoroalkylated arenes in high efficiency. The method features inexpensive and readily available reagents, excellent functional-group tolerance, and opens a new avenue for the precise installation of the difluoromethylene motif.
Sun et al. (Thu,) studied this question.