Asymmetric Synthesis of Trisubstituted Allenes: Copper-Catalyzed Alkylation and Arylation of Propargylic Phosphates

Asymmetric synthesis of trisubstituted allenes is accomplished by copper-catalyzed alkylation and arylation of propargylic phosphates using organoboron nucleophiles. Excellent chirality transfer and regioselectivity, together with good functional group compatibility, were observed in reactions with both alkyl boranes and arylboronic esters.