Redox-Triggered Switchable Synthesis of 3,4-Dihydroquinolin-2(1H)-one Derivatives via Hydride Transfer/N-Dealkylation/N-Acylation.

The switchable synthesis of 3-non, 3-mono, 3,3'-disubstituted 3,4-dihydroquinolin-2(1H)-ones was developed through a redox-neutral hydride-transfer/N-dealkylation/N-acylation strategy from o-aminobenzaldehyde with 4-hydroxycoumarin, and Meldrum's acid, respectively. The unprecedented strategy for the synthesis of 3,3'-highly functionalized 3,4-dihydroquinolin-2(1H)-one has been realized with the in situ utilization of the released HCHO via the o-QM involved Michael addition. In addition, the synthetic utility of this protocol has been well illustrated via concise synthesis of CYP11B2 inhibitor.