Ligand-Controlled Palladium-Catalyzed Regiodivergent Defluorinative Allylation of gem-Difluorocyclopropanes via sigma-Bond Activation

Comprehensive Summary Monofluoroalkenes are important and versatile privileged components in pharmacologically relevant molecules. Here, we report a method for the selective construction of these compounds in a diversity-oriented fashion through regiodivergent cross-coupling of gem-difluorocyclopropanes with allylboronates by employing a palladium catalyst with two different ligands, in which gem-difluorocyclopropanes were used as allyl electrophiles by C-C and C-F bond activation. In the presence of 2-biphenylyl(diphenyl)phosphine as ligand, the linear-selective allyl-allyl bond formation is highly obtained, while utilizing the sterically hindered BrettPhos (dicyclohexyl[3,6-dimethoxy-2',4',6'-tris(1-methylethyl)[1,1'-biphenyl]-2-yl]phosphine) as the ligand favors the generation of the branched-selective product. Experimental and computational studies investigated the key steps of the cross-coupling reactions, revealing the origin of the ligand-controlled regiodivergence.