Synthesis of α-Aminocarbonyl Compounds via Hetero Diels–Alder Reaction

A synthetic route to α-aminoketone derivatives via a hetero Diels–Alder reaction is described. Diacylhydrazine was oxidized by tert-butyl hypochlorite in the presence of pyridine. After evaporation, the hetero Diels–Alder reaction with diene was carried out without isolation of the azodicarbonyl compound. Quantitative hetero Diels–Alder reaction was possible with 1 equivalent of diene when Hf(OTf)4 or AgOTf was used as the catalyst. The N–N bond of the product was cleaved by SmI2-reduction in the presence of tert-BuOH in THF. Further, ozonolysis of the C=C double bond afforded the α-aminoketone derivative in excellent yield.