A new synthetic route to α,β-unsaturated N-acyl-α-amino acidesters (N-acyl-α-dehydroamino acidesters) is described. The dehydroamino acidesters were prepared by the dehydration of α-(N-acylhydro...
give 2-(N-acylamino)-3-bromo-2-alkenoic acid, while the bromination of 3 with NBS gave the corresponding N-bromo derivative (7), whose bromine atom gradually migrates to give t-butyl 2-(N-acylamino)-3-bromo-2-alkenoate. The substitution of the bromine of 7 with nucleophiles gave, successively, the corresponding N-methoxy, N-benzyloxy and N-cyano derivatives, while that with sodium azide gave the corresponding