Cp*Rh(iii)-catalyzed and solvent-controlled tunable [4 + 1]/[4 + 3] annulation for the divergent assembly of dihydrobenzo[cd]indoles and dihydronaphtho[1,8-bc]azepines

Abstract

Chemo- and regioselective Cp*Rh-catalyzed tunable [4 + 1]/[4 + 3] cyclization of free 1-naphthylamines with propargyl carbonates has been accomplished by regulating the reaction solvents. The reaction allowed a variety of dihydrobenzo[cd]indoles and dihydronaphtho[1,8-bc]azepines to be synthesized with broad functional group tolerance. In addition, mechanistic studies favored an intramolecular nucleophilic attack/protodemetalation/isomerization sequence or protonation/intramolecular nucleophilic substitution over β-O elimination/intramolecular cyclization.