[8+2] Formal Cycloaddition Reactions of Tropones with Azlactones under Brønsted Acid Catalysis and Synthesis of α‐(2‐Tropyl), α‐Alkyl α‐Amino Acids

Abstract

Abstract The reaction of tropones with azlactones catalyzed by Brønsted acids affords a variety of dihydro‐2 H ‐cyclohepta[ b ]furan derivatives, corresponding to a formal [8+2] cycloaddition process. They can easily be opened by nucleophiles to afford a new type of α,α‐disubstituted α‐amino acid (or peptide) containing seven‐membered rings at the quaternary position.