Rapid Access to Hindered α-Amino Acid Derivatives and Benzodiazepin-3-ones from Aza-Oxyallyl Cations.

Catalyst-free and mild synthetic methods for the construction of hindered α-amino acid derivatives are presented herein. A wide range of hindered amino acid amides can be readily obtained from the reaction of α-halohydroxamates with a variety of amines, including anilines, primary amines, and secondary amines. Moreover, the aza/aza-[4+3] cycloaddition of in situ-generated aza-oxyallyl cations with 2-aminophenyl α,β-unsaturated carbonyls to furnish seven-membered benzodiazepin-3-ones is reported for the first time.