Relay Organophotoredox/<i>N</i>-Heterocyclic Carbene Catalysis-Enabled Asymmetric Synthesis of Dibenzoxazepine-Fused Pyrrolidinones

Abstract

An unprecedented highly stereoselective synthesis of pyrrolo[1,2-<i>d</i>][1,4]oxazepin-3(2<i>H</i>)-ones has been accomplished via photoredox/<i>N</i>-heterocyclic carbene (NHC) relay catalysis. A wide range of substituted dibenzoxazepines and aryl/hetereoaryl enals were well accommodated under the organic photoredox catalysis-promoted amine oxidation to generate the imines, followed by a NHC-catalyzed [3 + 2] annulation reaction to achieve excellent diastereo- and enantioselectivities of the dibenzoxazepine-fused pyrrolidinones.