Halogen cation-promoted and solvent-regulated electrophilic cyclization for the regioselective synthesis of 3-haloquinolines and 3-halospirocyclohexadienones.

A novel approach for the production of halogen cations through the reaction of halogens with silver ions is described in this paper. On this basis, the regioselective synthesis of 3-haloquinolines and 3-halospirocyclohexadienones is realized through solvent regulation. The gram-scale reaction and the compatibility of complex substrates demonstrate the synthetic potential of this protocol, which will be an appealing strategy in organic synthesis.