Herein, we describe an efficient and selective Cucatalyzed CÀ H bond chalcogenation of the indolizine core, in the presence of DMSO and applying ultrasound irradiation as an alternative energy source. Under the optimal conditions, 3-sulfanylindolizines (16 examples) were prepared in moderate to good yields starting from diorganyl disulfides and 2-arylindolizines. When diphenyl diselenide was used, 1,3-bis (selanyl) indolizines (4 examples) were exclusively obtained in very good yields. The use of ultrasound irradiation makes the reaction faster and more selective when compared to conventional heating.

We established a new visible-light-mediated protocol for the regioselective βhydroxyselenylation of olefins, employing benzeneseleninic acid as substrate. Regarding a novel approach, the benzeneseleninic acid emerges as an efficient and affordable reagent to be used as an electrophilic selenium source that can be easily converted to selenium-based radical species under visible-light conditions. In this sense, the photocatalytically formed PhSe• radical can react directly with unsaturated substrates, including alkenes, to access a new C-Se bond and a carbon-centered radical intermediate, which finally is trapped by a hydroxyl radical species, delivering the βhydroxyselanyl compounds. Thus, despite the versatile utilities in organic synthesis, such as building blocks, the β-hydroxyselanyl compounds have demonstrated important biological activities. Based on that, we concentrated our efforts on developing a robust, effective, and environmentally benign methodology for their preparation. The optimal condition involves the reaction between styrene and 1.0 equivalent of phenylseleninic acid, in the presence of 5.0 mol% of eosin Y, as a cheap and easily available photocatalyst, with DMSO promoting the reaction medium. Satisfactorily, the system was irradiated with blue LED light for 2 h, to deliver the desired products in good yields.