Gold-catalyzed dual C–C bond cleavage of biphenylenes bearing a pendant alkyne at ambient temperature

We report a catalytic skeletal rearrangement of biphenylenes with a pendant alkyne moiety at room temperature by a cationic gold catalyst, which involves the cleavage of two bonds: the C-C bond of biphenylene and the C(sp)-C(sp(2)or sp(3)) bond. Experimental and theoretical studies revealed that the reaction mechanism included pi-activation of the alkyne, ring expansion and 1,2-carbon shift.