Access to Succinimidyl Spirocyclobutenes via Spiroannulation of Bicyclo[1.1.0]Butanes and Azaoxyallyl Cations

We herein disclose a base-mediated annulation reaction between azaoxyallyl cation and arylbicyclo[1.1.0]butane carboxylates (BCBs) to access succinimidyl spirocyclobutenes. The base played a dual role in forming the electrophilic azaoxyallyl cation species and also generating an enolate species from BCB and HFIP also assisted the stabilization of the intermediates and cyclization. Control experiments reveal the explicit involvement of the azaoxyallyl cation.