TMSOTf-Mediated Cascade Synthesis of Hexahydropyrrolo[2,3- b ]indoline Frameworks via the Meyer–Schuster Rearrangement

TMSOTf-promoted cascade reaction between protected tryptamine and propargyl alcohol has been developed as an efficient strategy for the construction of hexahydropyrrolo[2,3-b]indoline frameworks. The transformation enables access to an expanded chemical space around this important scaffold via a Lewis-acid-driven annulation strategy. The protocol proceeds through a Meyer-Schuster rearrangement, followed by regioselective C-3 nucleophilic addition of the indole ring and subsequent 5-exo-trig cyclization. This method affords structurally diverse hexahydropyrrolo[2,3-b]indolines in moderate to good yields.