Synthesis of functionalized spiro[indanone-benzazepine] scaffolds via [4 + 3] annulation reaction of N-(o-chloromethyl)aryl amides with ninhydrin-derived Morita−Baylis−Hillman carbonates

A [4 + 3] annulation of aza-o-quinone methides in situ-generated from N-(o-chloromethyl)aryl amides with ninhydrin-derived Morita−Baylis−Hillman carbonates was realized under mild conditions. This protocol provides an efficient and practical approach for assembling a novel functionalized heterocyclic system incorporating benzazepines and spiro indane-1,3-dione motifs in high yields (up to 95 % yields) with good functionality tolerance. Moreover, the potential application of the methodology was further highlighted by several synthetic transformations. The structure of the typical product was straightforwardly demonstrated by X-ray crystallography.