Stannylcupration of gamma-heterosubstituted acetylenic esters: a new route to 4-stannylated five membered N- and O-heterocylces

4-Tributylstannyl,2-(5H)-furanone and pyrrolone have been prepared in good yields by addition of mixed stannylcuprate reagent on ?-amino and ?-hydroxy acetylenic esters. The use of these compounds as useful intermediates for the selective functionalization of these heterocyclic rings is discussed