Lanthanum–Catalyzed One–Pot Synthesis of Chromeno–Fused Pyridine/Quinolinone Derivatives

A novel one‐pot approach has been developed for the preparation of 5‐oxo‐5 H ‐chromeno[4,3‐ b ] pyridine‐3‐carboxylates and 6 H ‐chromeno[4,3‐ b ] quinolin‐6‐ones by reacting 2‐((benzylimino/phenylimino)‐methyl) phenols with ethyl/methyl propiolate in presence of La(OTf) 3 under thermal conditions. The reactions proceeded through the formation C−O, C−N and C−C bonds to form the title compounds. The bio–active compound 6 H ‐chromeno[ 4,3‐b ] quinolin‐6‐one has been prepared by this protocol.