Iridium-Catalyzed Decarboxylative Annulation of 2- o -Carboranylbenzoic Acids with Internal Alkynes

An iridium-catalyzed decarboxylative annulation of 2- o -carboranylbenzoic acids with internal alkynes via B–H activation has been developed. A series of naphtho- o -carborane derivatives were produced in moderate to excellent yields with exclusive B(4) regioselectivity. The mechanistic study suggests that the rate-determining step does not involve the B–H bond cleavage. The photophysical properties of products reveal a distinct substituent effect, with aryl donor/acceptor strength modulating the charge-transfer character and emission behavior.