Convergent Azaspirocyclization of Bromoarenes with N-Tosylhydrazones by a Palladium Catalyst

1-Azaspirocyclic compounds have gained attention in chemistry and drug discovery fields. In this manuscript, the development of a Pd-catalyzed dearomative azaspirocyclization of bromoarenes bearing an aminoalkyl group with N-tosylhydrazones is described. The present method enables azaspirocyclization with the introduction of carbon substituents, achieving the convergent synthesis of 1-azaspirocycles. This method allowed furan, thiophene, and naphthalene cores to generate the corresponding 1-azaspirocycles. The obtained azaspirocycles from furans were further elaborated via an acid-catalyzed rearrangement to afford 1-azaspirocyclopentenones.