Asymmetric synthesis of methyl (2R,3S)-3-(4-methoxyphenyl) glycidate, a key intermediate of diltiazem, via Mukaiyama aldol reaction

Methyl (2R,3S)-3-(4-methoxyphenyl) glycidate, a key intermediate of diltiazem, was synthesized in good yield with high enantioselectivity based on chiral oxazaborolidine-mediated Mukaiyama aldol reaction of p-anisaldehyde with α,α-dichloro silyl ketene acetal (up to 96% ee), followed by reduction and cyclization.