Photooxidative C–C double bond cleavage of β-enaminocarbonyl compounds: toward selective <i>N</i>-formylation of amines

A photooxidative C-C double bond cleavage of electron-deficient β-enaminocarbonyl compounds possessing a silyl group at the α-position to the nitrogen atom using methylene blue (MB) as the photosensitizer was explored. Photochemically generated ¹O₂ was added across the CC bond with the aid of a tethered silyl group to cleave it and form <i>N</i>-formylamines. This reaction protocol exhibited compatibility with numerous β-enaminocarbonyl substrates, including those with various <i>N</i>-alkyl, <i>N</i>-benzyl and <i>N</i>-aryl substituents.