Synthesis of pyrrolo[3,4-c]pyridines via metal-free cross-coupling/cyclization cascades of β-ketothioamides with 2-aroylmalononitrile at room temperature

Abstract

We herein report a metal-free, chemo- and site-selective strategy to synthesize pyrrolo[3,4-c]pyridines using β-ketothioamides and 2-aroylmalononitrile at room temperature in open air. The base-assisted approach proceeds through cross-coupling/two-fold intramolecular cyclization cascades enabling direct access to pyrrolo-fused pyridines via sequential formation of C–N, CO, C–C and C–N bonds. The O₂ as a green oxidant, scalability and H₂O as a sole by-product are the additional benefits.