Chiral synthesis via organoboranes. 31. A simple synthesis of enantiomerically pure (Z)- and (E)-Alkenes, (Z)-RCHCHR* and (E)-RCHCHR*

Abstract The monoisopinocampheylorganylboranes, IpcR*BH, readily available in purities ⩾99% ee by the asymmetric hydroboration of alkenes with monoisopinocampheylborane, IpcBH 2 , are easily transformed into enantiomerically pure ( ⩾99% ce ) (Z)- and ( E )-alkenes. The generality of the procedure was demonstrated by synthesizing four each (Z)- and ( E )-alkenes. This new procedure makes the enantiomerically pure compounds readily available and contributes another stage to the completion of our goal of providing a truly general asymmetric synthesis of pure enantiomers.