Rh-Catalyzed regioselective C7Ar-allylation of tryptophan with VCC and its late-stage peptide diversification.

N-Pivaloyl-directed Rh(III)-catalyzed regioselective C7Ar-allylation of protected tryptophans was achieved with vinyl-1,3-dioxolan-2-one, furnishing C7Ar-(hydroxymethyl)allylated tryptophan-based unnatural amino acids in high yields. Furthermore, the late-stage exemplification of the strategy was successfully accomplished in tryptophan-containing dipeptides, tripeptides and tetrapeptides. Slight modification in the reaction conditions enabled the formation of C7Ar-(formyl)allylated tryptophan-based unnatural amino acids and dipeptides in moderate yields.