Skeletal Transformation of Oxindoles into Quinolinones Enabled by Synergistic Copper/Iminium Catalysis

We describe a synergistic Cu/secondary amine catalysis for skeletal transformation of an oxindole core into a quinolinone skeleton, which generates several structurally new pyridine-fused quinolinones. The synergistic reactions allow expansion of a five-membered lactam ring by radical cation -triggered C-C bond cleavage and enable a further intramolecular cyclization with the aim to construct totally distinct core skeletons.

Automated summary

We present a synergistic Cu/secondary amine catalysis for the transformation of an oxindole core into a quinolinone skeleton, leading to the formation of novel pyridine-fused quinolinones. This synergistic reaction involves the expansion of a five-membered lactam ring through radical cation-induced C-C bond cleavage, followed by an intramolecular cyclization to generate distinct core skeletons.