Synthesis of (−)‐Cytoxazone and (+)‐epi‐Cytoxazone: The Chiral Pool Approach

Immunomodulator (−)‐cytoxazone and its epimer (+)‐epi‐cytoxazone were synthesized starting from (D)‐(−)‐4‐hydroxyphenylglycine. Homologation of the amino acid was achieved via the corresponding aldehyde, by a cyanohydrin reaction. The racemization of highly sensible amido aldehyde was efficiently suppressed when the oxidation of the parent aminoalcohol was performed by a modified Dess‐Martin procedure.