Diastereoselective synthesis of spiro-cyclopropanyl-cyclohexadienones via direct sulfide-catalyzed [2 + 1] annulation of para-quinone methides with bromides.

An efficient sulfide-catalyzed [2 + 1] annulation of para-quinone methides (p-QMs) with diverse bromides has been achieved. This catalytic strategy provides an efficient and straightforward protocol for accessing a variety of spiro-cyclopropanyl-cyclohexadienone compounds in good to excellent yields (64% to 96% yields) with outstanding diastereoselectivities (>20 : 1 dr), displaying good functional group tolerance as well as gram-scale capacity.