Synthesis of 1,4-Dicarbonyl Compounds from Silyl Enol Ethers and Bromocarbonyls, Catalyzed by an Organic Dye under Visible-Light Irradiation with Perfect Selectivity for the Halide Moiety over the Carbonyl Group
We report the visible-light-induced radical coupling reaction of silyl enol ethers with α-bromocarbonyl compounds to give 1,4-dicarbonyls. The reaction was effectively accelerated using an inexpensive organic dye (eosin Y) as a photoredox catalyst. 1,4-Dicarbonyl compounds alone were afforded, without the generation of carbonyl adducts of the α-halocarbonyls, which are usually generated in the presence
Benzoyl radicals are generated directly from (hetero)aromaticaldehydes upon tetrabutylammonium decatungstate ((n-Bu4N)4W10O32), TBADT) photocatalysis under mild conditions. In the presence of α,β-unsaturated esters, ketones and nitriles radical conjugate addition ensues and gives the corresponding β-functionalized aryl alkyl ketones in moderate to good yields (stereoselectively in the case of 3-m