Nitrite-catalyzed economic and sustainable bromocyclization of tryptamines/tryptophols to access hexahydropyrrolo[2,3-b]indoles/tetrahydrofuroindolines in batch and flow
A highly efficient and concise bromocyclization has been successfully achieved, in which tryptamine/tryptophol derivates can be transformed to valuable HPI/TFI scaffolds with economic and green manners. Moreover, a controllable cascade transformation of bromocyclization and aromatic bromination has also been smoothly achieved to form dibrominated HPIs and TFIs. Production could be successfully scaled