TBAI‐Catalysed Formal [4+4]‐Cycloaddition: Easy Access to Oxa‐Bridged Eight‐Membered Heterocycles

Abstract

AbstractTBAI‐catalysed [4+4]‐cyclization reaction of anthranils with hydrazones to deliver oxa‐bridged eight‐membered heterocycles in accepted yields was developed. Preliminary mechanistic studies indicated that the reaction involved the in situ generation of vinyldiazenes from readily available hydrazones followed by an aza‐Michael addition of the anthranil substrates onto the vinyldiazenes and subsequent annulation. This transformation involved the formation of two new C−N bonds and C−O bond in one pot, overcoming the synthetic limitations of anthranils in organic chemistry. This strategy benefits from high efficiency and atomic economy with mild reaction conditions.