Tandem copper-catalyzed enantioselective allylation-metathesis.

Grignard reagents undergo enantioselective (up to 86% ee) copper-catalyzed S(N)2' substitution on achiral allylic chlorides. The reaction is wide in scope for both the Grignard reagent and the allylic substrate. The resulting terminal alkene could be submitted to intra- or intermolecular metathesis to afford new chiral synthons. The experimental conditions are compatible with a one-pot overall substitution-metathesis procedure without loss of enantioselectivity. [reaction: see text]