Efficient cyclotrimerization of bicyclic vic-bromostannylalkenes promoted by copper(I) thiophen-2-carboxylate.

Copper(I) thiophen-2-carboxylate was successfully employed in the trimerization of [2.2.1] bicyclic vic-bromotrimethyltin olefins (in their racemic composition), bearing different functionalities, to invariably obtain almost quantitative yields of the syn and anti tris-annelated benzenes.