The first visible-light-mediated photoredox oxidative approach for generating carbamoyl radicals from oxamic acids is disclosed. Reaction of the generated carbamoyl radicals with electron-deficient alkenes opens efficient access to 3,4-dihydroquinolin-2(1 H)-ones under mild conditions through a sequence of intermolecular radical addition, cyclization, and aromatization. The process is compatible with a variety of oxamic acids and electron-deficient alkenes, and a wide variety of 3,4-dihydroquinolin-2(1 H)-ones were prepared.

An efficient silver-catalyzed tandem decarboxylative radical addition/cyclization of oxamic acids with alkenes has been developed. This method provides a novel and straightforward protocol toward a variety of 4-aryl-3,4-dihydroquinolin-2(1H)-ones, 4-(α-carbonyl)-3,4-dihydroquinolin-2(1H)-ones, and quinolin-2(1H)-ones in aqueous solution.

A new protocol for orthogonal sp3 C1?H and N?H bond functionalization of 1,2,3,4-tetrahydroisoquinolines has been established via the Ugi four-component reaction with aldehydes, isonitriles, and carboxylic acids. It was revealed that only the N?H bond could be functionalized when the reaction was performed in acetonitrile at room temperature; however, when the reaction was carried out in toluene at 80??C, redox-neutral sp3 C1?H bond functionalization of 1,2,3,4-tetrahydroisoquinolines was achieved. Differing from the common role of carboxylic acid as a promoter in redox-neutral amine ?-functionalization, the carboxylic acid employed herein is also a reactant. The orthogonal process is compatible with various substrates and provides an appealing? access to a library of structurally diverse 1,2,3,4-tetrahydro?isoquinolines.

An expedient organic photoredox Pschorr reaction has been developed that opens up a synthetic route to 6H-benzo[c]chromenes. The process can be performed under mild conditions by using eosin Y as a photoredox catalyst and acetonitrile as the solvent. The diazonium salts can be either preformed or generated in situ from the corresponding amines with t-BuONO. The process is amenable to gram-sale synthesis of 6H-benzo[c]chromenes, which can be further transformed into both 6H-benzo[c]chromen-6-ones through oxidation or to 6H-benzo[c]chromen-6-amine through sp3 C–H bond amination. The protocol provides an attractive route for the synthesis of a library of 6H-benzo[c]chromes.

A photoredox one-pot strategy for efficient accessing 3,4-dihydroquinolin-2(1H)-ones from anilines, oxalyl chloride, and electron-deficient alkenes is disclosed. The new approach features excellent synthetic efficiency, readily available starting materials, and simple operations. It is compatible with a variety of anilines and electron-deficient alkenes. A broad array of 3,4-dihydroquinolin-2(1H)-ones were prepared.