Carbon–Carbon Bond Formation at a Neutral Terminal Carbido Ligand: Generation of Cyclopropenylidene and Vinylidene Complexes

Abstract

A C1 source, the carbido complex [Ru(C)(PCy3)2Cl2] (1) adds cleanly to dimethylacetylene dicarboxylate (DMAD), affording the cyclopropenylidene complex 2 (red O, green Cl, yellow P, gray C). This product is surprising given the instability of its trans-cyclopropylidene analogue. HX reagents effect 1,1-addition and ring opening, forming vinylidene complexes such as 3 which catalyze the ring-opening metathesis polymerization of norbornene.