ChemInform Abstract: Formation and Reaction of 2-Metalated N-Boc-4,4-dimethyl-1,3-oxazolidines in the Presence of (-)-Sparteine: New Chiral Formyl Anion Equivalents

Lithiation of N -Boc-4,4-dimethyl-1,3-oxazolidine with s -BuLi and the following reaction with benzaldehyde was carried out in the presence of (−)-sparteine. The reaction was not diastereoselective ( syn : anti =46:54), but each isomer of the adducts was obtained enantioselectively ( syn : 90% ee, anti : 88% ee). Addition of MgBr 2 to the reaction mixture increased the diastereoselectivity to syn : anti =90:10.