Thiol and Disulfide Derivatives of Ephedra Alkaloids 2: A Mechanistic Study of Their Effect on the Addition of Diethyl Zinc to Benzaldehyde

Article abstract of DOI:10.1016/0957-4166(95)00237-J

Thiol and disulfide derivatives of ephedrine have been shown previously to catalyse in high enantiomeric excess (ee) the reaction of diethyl zinc with benzaldehyde.We find that this reaction involves non-linear correlations between the ee of product and catalyst.Osmotic measurements indicate a high degree of aggregation of the zinc thiolates.The behaviour of the thiol derivatives deviates sharply from that of the oxygen analogue, N-methyl ephedrine.