The rapid development of organocopper chemistry, particularly since the middle of the last century, has been comprehensively documented.[1] Alkynylcopper (I) compounds have been known for many years,[2] and various methods are available for their preparation.[3] Reactions of arylethynylcopper (I) compounds were exploited by Castro and coworkers in stoichiometric reactions,[4] notably in heterocyclic synthesis.[5] Compared with the ...