[2 + 2]Cycloaddition of Norbornenes with Alkynes Catalyzed by Ruthenium Complexes

Abstract

The first CC coupling catalyzed by a neutral Cp*Ru complex ([Cp*RuCl(cod)]) is reported in the reactions of norbornenes and norbornadiene (1) with different alkynes (2). Besides the [2 + 2] cycloadducts 3, the reaction with terminal alkynes and 1 unexpectedly also yields the 1,3-benzene derivatives 4.