Rh(iii)-catalyzed domino annulation strategy to synthesize benzo[c]naphthyridinones from 3-diazooxindoles and isoxazolones

Abstract

A convenient methodology for the synthesis of benzo[c]naphthyridinone derivatives was developed via a Rh(III)-catalyzed and Cu(I)-oxidized annulation of 3-diazooxindoles with 3-aryl-5-isoxazolones. This transformation involves the in situ generation of a tricyclic core through an unprecedented ring-expansion of 3-diazooxindoles with good functional group tolerance. Consecutive C–C and C–N bond formations and CO₂ elimination are the key steps for success, as demonstrated by detailed DFT studies.