Transition-metal-free, visible-light-induced multicomponent synthesis of allylic amines and tetrahydroquinolines

Abstract

A visible-light-induced, 1,2,3,5-tetrakis-(carbazol-yl)-4,6-dicyanobenzene (4CzIPN) catalyzed synthesis of allylic amines from secondary alkylamines, alkyl-substituted carbonyls, and vinyl sulfones through ‘all-alkyl’ α­amino radicals has been developed. In another similar photoreductive system, 4CzIPN...

Palladium-catalyzed intramolecular oxypalladation-initiated cascade: solvent-dependent chemodivergent approach to functionalized benzazepines and tetrahydroquinolines

“…11 Owing to the tremendous biological and medicinal significance of benzazepines and tetrahydroquinolines, the development of straightforward synthetic transformations to access these valuable heterocycles is highly desirable. 12,13 Consequently, as part of our continuous research interest in developing nucleopalladation-initiated cascade reactions of alkynes, 14 we aimed to develop palladium-catalyzed, chemodivergent, intramolecular oxypalladation-initiated cascade sequences for the direct synthesis of isochromenone fused benzazepines/benzoxepines 2 and isobenzofuranone-fused tetrahydroquinolines/chromanes 3 starting from alkynes 1 bearing tethered nucleophilic carboxylic ester and electrophilic enone functionalities (Scheme 1). We surmised that the role of solvents in the proposed cascade transformations is crucial and it would be possible to achieve the proposed 6-endo-dig and 5-exo-dig cyclizations and the successive carbopalladation (olefin insertion) cascade reactions of substrates 1 to access the functionalized isochromenone-fused heterocycles 2 (Scheme 1, eqn ( 1)) and isobenzofuranone-fused tetrahydroquinolines/chromanes 3 (Scheme 1, eqn (2)).…”