Enantiospecific total synthesis of TAN1251C and TAN1251D

An enantiospecific total synthesis of TAN1251C and TAN1251D has been achieved. An aromatic oxidation reaction of a secondary amine, which is prepared from two molecules of L-tyrosine derivatives, with hypervalent iodine reagent gave a spirocyclic product as a key intermediate for the synthesis of TAN 1251C and D.