Intramolecular Buchwald-Hartwig N-Arylation of Bicyclic Hydrazines: Practical Access to Spiro[indoline-2,3'-piperidines]

In recent years, spirocycles have been the focus of medicinal chemistry, and several drugs or drug candidates incorporating these “non-planar” chemical motifs have been developed. New advancements in this field, however, are greatly limited by the lack of innovative methods enabling the preparation of original spirocyclic cores. Here-in, an unprecedented intramolecular Buchwald-Hartwig N-arylation of bicyclic hydrazines is described. This key reaction gives access to unique spiro[indoline-2,3'-piperidine] derivatives after reductive cleavage of the nitro-gen–nitrogen bond. This approach widens the chemical space of spirocycles and may reveal useful to explore new avenues of research in drug discovery.