Photooxidative C-C double bond cleavage of β-enaminocarbonyl compounds: toward selective -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 O was added across the CC bond with the aid of a tethered silyl group to cleave it and form -formylamines. This reaction protocol exhibited compatibility with numerous β-enaminocarbonyl substrates, including those with various -alkyl, -benzyl and -aryl substituents.

Triplet Energy Transfer (EnT)-Promoted 1,3-Dipolar Cycloaddition Reactions of -(Trimethylsilyl)methylphthalimide with Electron-Deficient Alkynes and Alkenes.

Triplet energy transfer (EnT)-promoted photochemical pathways, arisen by visible light and its photosensitizers, have gained significant attention as a complementary strategy for initiating organic transformations in photochemical reactions that are unlikely to occur through a single electron transfer (SET) process. In the present study, we investigated the triplet EnT-promoted 1,3-dipolar cycloaddition reactions of -(trimethylsilyl)methylphthalimide with electron-deficient alkynyl and alkenyl dipolarophiles. The triplet excited state of -(trimethylsilyl)methylphthalimide, promoted by the triplet EnT from thioxanthone (TXA) photosensitizer, underwent sequential intramolecular SET and carbon-to-oxygen migration of the silyl group to form azomethine ylide.