Efficient preparation of aminoxyacyl amides, aminoxy hybrid peptides, and α-aminoxy peptides

(Chemical Equation Presented) N-(Pg-α-aminoxy acids) 1a-g are converted to N-(Pg-α-aminoxyacyl)benzotriazoles 2a-g, which react under mild conditions with amines, α-amino acids/α-dipeptides, and α-aminoxy acids to give aminoxyacyl amides 3a-g, (3e+3e′), and (3g+3g′), aminoxy hybrid peptides 4a-h, (4a+4a′), 6a-d, 9a-e, (9a+9a′), and (9b+9b′), and α-aminoxy peptides 10a,b in good yields without racemization.