Asymmetric Alkynylation of Aldehydes Catalyzed by an In(III)/BINOL Complex

Asymmetric alkynylation of both aromatic and aliphatic aldehydes using catalytic amounts of In(III)/BINOL is described. Dual activation of both substrates due to the "bifunctional character" of the indium(III) catalyst enables a broad range of substrate generality with high enantioselectivity (83 to >99% ee).