Stereoisomerically Pure Trisubstituted Vinylaluminum Reagents and their Utility in Copper‐Catalyzed Enantioselective Synthesis of 1,4‐Dienes Containing Z or E Alkenes

The desired isomer of a chiral 1,4-diene containing an E or Z double bond can be accessed readily by a regio- and stereoselective hydroalumination of silyl-substituted alkynes and subsequent enantioselective copper-catalyzed allylic alkylation. The utility of the procedure was demonstrated through the synthesis of (−)-nyasol (see scheme). dibal-H=diisobutylaluminum hydride, NHC=N-heterocyclic carbene.