One-pot synthesis of azepine spiro[4.6]-γ-lactams by a Hantzsch-type reaction

A facile route to spiro-γ-lactams containing fused seven- and five-membered rings is showcased here in a multicomponent reaction harnessing glycine. Four spiro-γ-lactams were characterised, including by X-ray diffraction techniques, showing them to be trapped unstable intermediates of the Strecker degradation. This hitherto unknown reaction pathway was investigated with mass spectrometry, revealing a plausible reaction mechanism.