Synthesis of gem-Diboromethyl-Substituted Bicyclo[1.1.1]pentanes and Their Application in Palladium-Catalyzed Cross Couplings.

We describe the first general transition-metal-free synthesis of gem-diboromethyl-substituted bicyclo[1.1.1]pentane (BCP) and other related C(sp3)-rich carbocyclic benzene bioisosteres from their corresponding p-tosylhydrazones. These novel functionalized benzene bioisosteres demonstrated unique reactivities toward palladium-catalyzed C(sp2)-C(sp3) cross couplings. The overall transformation can be applied to relatively complex substrates with potential utility in drug discovery.