An approach for the diastereoselective synthesis of (R)-(+)-methyl pipecolate and (+)-dextro-erythrophacetoperane from (S)-(−)-methylbenzylamine

A diastereoselective synthesis for the preparation of (R)-methyl pipecolate and dextro-erythrophacetoperane, analogs of methylphenidate, drugs used to treat attention deficit hyperactivity disorder, is reported. The key steps involve a high diastereoselective ring-closing reaction via enolate formation and a diastereoselective ketone reduction reaction. The total synthesis of these valuable drugs could be obtained in only 5 and 8 steps, respectively, starting from (S)-(−)-methyl benzylamine.