Visible Light-Induced Radical Cascade Difluoromethylation/Cyclization of Unactivated Alkenes: Access to CFH-Substituted Polycyclic Imidazoles.

An efficient and mild protocol for the visible light-induced radical cascade difluoromethylation/cyclization of imidazoles with unactivated alkenes using easily accessible and bench-stable difluoromethyltriphenylphosphonium bromide as the precursor of the -CFH group has been developed to afford CFH-substituted polycyclic imidazoles in moderate to good yields. This strategy, along with the construction of Csp-CFH/C-C bonds, is distinguished by mild conditions, no requirement of additives, simple operation, and wide substrate scope. In addition, the mechanistic experiments have indicated that the difluoromethyl radical pathway is essential for the methodology.

Visible-Light-Mediated Tandem Difluoromethylation/Cyclization of Alkenyl Aldehydes toward CFH-Substituted Chroman-4-one Derivatives.

An efficient and facile visible-light-mediated tandem difluoromethylation/cyclization of alkenyl aldehydes, with easily accessible and air-stable [PhPCFH]Br as the difluoromethylation reagent, has been established. A range of CFH-substituted chroman-4-one skeletons and their derivatives, such as 2,3-dihydroquinolin-4(1)-ones, chroman, 3,4-dihydronaphthalen-1(2)-one, 2,3-dihydrobenzofuran, and 2,3-dihydro-1-inden-1-one, are efficiently produced in moderate to good yields with excellent chemoselectivity under mild reaction conditions.

Transition-metal-free three-component coupling approach to QUINAP derivatives.

The aluminum(III) triflate catalyzed three-component coupling reaction of alkynes, amines and phosphorylated aryl aldehydes to access phosphoryl quinoline derivatives has been developed. The reaction proceeds in a simple system without the use of transition metals, ligands or additives, thus making it attractive for the fast preparation of a variety of new potential N-P bidentate ligands.

Visible-light-mediated tandem phosphorylation/cyclization for the synthesis of phosphorylated oxindoles.

The visible-light-mediated tandem phosphorylation/cyclization of -arylacrylamides with H-phosphine oxides has been developed for the synthesis of phosphorylated oxindoles. This efficient and facile process was useful for the construction of a C-P bond and triggered the formation of a C-C bond with good compatibility with functional groups undermild reaction conditions.