Easy Access to N,N -Disubstituted 2-Imidazolidinones from Weinreb-Type Amides and Enamides via Visible-Light-Mediated Radical Smiles Rearrangement

This paper describes a visible-light-driven photoredox catalytic strategy for the facile preparation of N,N-disubstituted-2-imidazolidinones from Weinreb-type amides (WAs) and N-acyl enamines. The reaction commences with the photoredox-catalyzed heterolysis of the N–O bond in the WAs, generating a nitrogen-centered amidyl radical. This radical subsequently adds to the enamine with high regioselectivity, triggering a tandem process comprising a radical Smiles rearrangement and an intramolecular acyl-retentive cyclization. This cascade ultimately leads to the formation of a highly reconstructed 2-imidazolidinone scaffold. This study presents a novel, straightforward approach to the synthesis of diversely substituted 2-imidazolidinones.