Carbolithiation of Chloro‐Substituted Alkynes: A New Access to Vinyl Carbenoids

Abstract

The intramolecular carbolithiation of a series of chloro-substituted alkynes leads to exocyclic alkylidene carbenoids of which both nucleophilic and electrophilic characters can be drove. A sole stereoselective 5-exo-dig addition takes place, probably because of a strong and persisting Li-Cl interaction arising before the transition state.