Phenyliodine diacetae (PIDA) oxidn. of N-benzyl-N-(benzyloxycarbonyl)tyrosine followed by quenching with aq. sodium chloride or bromide soln. gave the corresponding dihalocyclohexadienone lactones I [R = Cl, Br; R1 = N(CH2Ph)CO2CH2Ph]. With p-hydroxydihydrocinnamic acid similar PIDA oxidn. was obsd. to give I (R = Cl, Br; R1 = H). A plausible mechanism for the reaction is also described.
(1992), 33(43), 6491-4