Vinylic tellurides as precursors in a stereoselective and convergent route to Z-enynes and Z-trisubstituted enediynes

vinylic tellurides of z configuration are transformed into higher order z-vinyl cyanocuprates by transmetallation with higher order lithium dimethyl- or n-butyl(thienyl)cyanocuprates. reaction of the obtained z-vinyl cyanocuprates with zinc chloride gives presumably mixed zinc-copper species which react with bromoalkynes leading to enynes and enediynes with retention of the z double bond configuration.