An operationally simple protocol for the photocatalytic carbamoylation of imines is reported. Easily available, bench-stable 4-amido Hantzsch ester derivatives serve as precursors to carbamoyl radicals that undergo rapid addition to N-aryl imines. The reaction proceeds under blue light irradiation in the presence of the photocatalyst 3DPAFIPN and Brønsted/Lewis acid additives. Mechanistic studies indicated a photoredox mechanism that involves carbamoyl radicals.

A photocatalytic synthesis of 1,5-diaryl pyrazoles from arenediazoniums and arylcyclopropanols is reported. The reaction proceeded under mild conditions (rt, 20 min) with catalytic [Ru­(bpy)3]2+ under blue-light irradiation and exhibited compatibility with several functional groups (e.g., I, SF5, SO2NH2, N3, CN) and perfect levels of regiocontrol. Mechanistic studies (luminescence spectroscopy, CV, DFT, radical trapping, quantum yield determination) documented an initial oxidative quenching of the excited photocatalyst and the operation of a radical-chain mechanism.

Functionalization with C1‐building blocks are key synthetic methods in organic synthesis. The low reactivity of the most abundant C 1 ‐molecule, carbon dioxide, makes alternative carboxylation reactions with CO 2 ‐surrogates especially important. We report a photoredox‐catalyzed protocol for alkene carbamoylations. Readily accessible 4‐carboxamido‐Hantzsch esters serve as convenient starting materials that generate carbamoyl radicals upon visible light‐mediated single‐electron transfer. Addition to various alkenes proceeded with high levels of regio‐ and chemoselectivity.

A mild and operationally simple protocol for the deoxygenation of a variety of heteroaryl N-oxides and nitroarenes has been developed. A mixture of substrate and Hantzsch ester is proposed to result in an electron donor–acceptor complex, which upon blue-light irradiation undergoes photoinduced electron transfer between the two reactants to afford the products. N-oxide deoxygenation is demonstrated with 22 examples of functionally diverse substrates, and the chemoselective reduction of nitroarenes to the corresponding hydroxylamines is also shown.

The peculiar versatility of remotely enolizable 6-methyluracil-5-carbaldehydes as useful vinylogous pronucleophiles in direct, asymmetric [4 + 2] cyclizations with suitable nitroolefins has been demonstrated. Under the strategic exploitation of noncovalent bifunctional organocatalysis, a dearomative remote enolization strategy was implemented, to generate oQDM-type dienolate intermediates that were efficiently and stereoselectively trapped by either aromatic or aliphatic nitroolefins. A series of functionalized, chiral carbocycle-fused uracils embedding three contiguous stereocenters were thus collected in one step in good yields, with generally good levels of enantioselectivity, and complete diastereocontrol. Furthermore, the ability to provide enantiopure products via simple one-cycle recrystallizations and the possibility to further functionalize these scaffolds without losing their chiral integrity were demonstrated.