The convergent total synthesis of cryptophycins C and D is described. It has been shown that in both natural products the absolute configuration of the alpha-amino acid corresponds to the D-series. The structural assignment for cryptophycin C has been corrected to reflect this fact, Since the structure of cryptophycin A has been correlated to cryptophycin C, the chloro-O-methyltyrosine unit in cryptophycin A has the D-configuration.