An efficient and high-yielding approach for the asymmetricsynthesis of calcimimetic (+)-NPS R-568 (1) has beendeveloped. The key step of the synthesis is the highlydiastereoselective addition of methyl Grignard to the (SS,E)-N-(3-methoxybenzylidene)-2-propanesulfinamide [5(S)], whichafforded a single diastereoisomer in high yield in shortreaction time