Kinetic resolution of secondary alcohols using proline-derived bicyclic iminium salts

Article abstract of DOI:10.1016/S0040-4039(97)00815-0

The proline-derived bicyclic iminium salt 3 can be used to bring about kinetic resolution in its reaction with salts of secondary alcohols to give the corresponding methyl sulfides. Reaction proceeds most efficiently with sodium 1-phenylethoxide in toluene at RT where either 3 or the benzyl salt 14 give e.e.s of 21-25% and changing the heteroatoms present in the sails, the metal cation used and the solvent and temperature all give similar or lower selectivity.