The Simmons–Smith reaction offers a direct route for conversion of an alkene into a cyclopropane with a zinc carbenoid as the active intermediate. Zinc carbenoids however have never delivered a...

A novel one-pot reaction producing a metal vinylidene structure in a five-membered ring by cyclization of a multiyne has been achieved. The ring strain and the high stability of the cyclic metal vinylidene complexes have been analyzed experimentally and computationally. The metal vinylidene unit in a fused-ring complex is unreactive to both nucleophiles and electrophiles. It reacts however at the nearby carbonyl group achieving the unprecedented conversion of metal tributing factors for the aromaticity-driven process has been studied by DFT calculations.