Reversal of predominant enantioselectivity in the asymmetric alkynylation reaction using sulfamide-amine alcohols

The change of substituent in the backbone of l-proline-derived sulfamide-amine alcohol ligand 3 provides chiral propargylic alcohols with the opposite configurations in significant enantioselectivities in the asymmetric addition of phenylacetylene to aldehydes. Meanwhile, the ligand 3 in combination with Ti(OiPr)4 could also afford the products with opposite absolute configuration in high yields.