Cu(OAc)2/Cs2CO3-promoted one-pot synthesis of 2,3-disubstituted quinolin-4(1H)-ones from spiro[indole-3,5′-isoxazoles]

Abstract

A concise one-pot method for the synthesis of 2‑aroyl‑3‑arylquinolin‑4(1H)-ones has been developed using readily accessible 4’H‑spiro[indole‑3,5′‑isoxazoles] as precursors. Under basic Cu‑assisted conditions, the spirocyclic substrates undergo a cascade transformation to deliver the target quinolin-4(1H)-ones in moderate to good yields. The process proceeds without isolating phenylacetonitrile or indoxyl intermediates and offers a practical alternative to existing multistep approaches, expanding the synthetic utility of spiroindole‑based cascade chemistry.