Gold-catalyzed [5+2] cycloaddition of quinolinium zwitterions and allenamides as an efficient route to fused 1,4-diazepines.

Herein, we demonstrate a new catalytic cycloaddition of quinolinium zwitterions involving a gold-bound allylic cation intermediate. This ligand-free higher-order cycloaddition efficiently affords a variety of fused 1,4-diazepine derivatives in a stereospecific manner at room temperature.