Highly enantioselective alkynylation of aldehydes using a new BINOL/Ti(OiPr)4/chiral sulfonamide catalyst system.

A series of sulfonamides (2-4) were prepared from natural amino acids and used as additives in the BINOL-Ti(OiPr)(4) catalyzed enantioselective alkynylation of aldehydes. The reactions proceeded smoothly with good yields and very high ee's (up to 99%) in most cases.