(IMes)-Copper Complex for Methylenation and Grignard Reactions

Chloro(1,3-dimesitylimidazol-2-ylidene)copper(I) (1) is an effective catalyst for the methylenation of a variety of aliphatic and aromatic aldehydes and ketones with trimethylsilyldiazomethane and triphenylphosphine.¹⁾ The methylenation reaction is applied to a one-pot methylenation-Diels–Alder cyclization,²⁾ and a one-pot methylenation-intramolecular Heck reaction.³⁾ The complex 1 also catalyze the allylic substitution reactions with Grignard reagents.⁴⁾