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( sp 3 )-rich carbocyclic benzene bioisosteres from their corresponding p -tosylhydrazones. These novel functionalized benzene bioisosteres demonstrated unique reactivities toward palladium-catalyzed C( sp 2 )-C( sp 3 ) cross couplings. The overall transformation can be applied to relatively complex substrates with potential utility in drug discovery.