Regiospecific and stereoselective synthesis of functionalized and differently metalated alkenes by silyl- or stannylcupration of metalated acetylenes

Differently metalated vinylcuprate intermediates resulting from silyl- or s tannylcupration of silyl- and tin-containing acetylenes reacted with a rang e of electrophiles, including chlorosilanes and chlorostannanes, affording regio- and stereodefined differently metalated vie and gem silyl- and tin-t risubstituted alkenes, Some of these functionalized polymetalated olefins a re interesting synthons in organic chemistry.