Direct synthesis of 1,3-dithiolanes from terminal alkynesviavisible light photoredox catalysis

Abstract

AA visible light-mediated, metal-free, regioselective dihydrothionation of terminal aromatic as well as heteroaromatic alkynes has been achieved by using Eosin Y as a photoredox catalyst at room temperature. The protocol...

Photocatalytic Chemodivergent Synthesis of α‐gem‐Dihalovinyl Ketones and Chromen‐2‐Ones from Monoalkynes

“…[8] Specifically, visible light photocatalytic functionalizations of alkynes appear as a powerful tool for the collection of functional molecules across its π-system. [9] Moreover, the visible-lightinduced Kharasch-type addition enables a facile and atom-economic approach to produce polyhalogenated compounds under sustainable conditions, [10] which provides excellent opportunities for late-stage modifications via modern cross-coupling reactions. [11] For instance, we recently reported a photocatalytic Kharasch-type addition-bicyclization of aromatic 1,7-diynes with CBrCl 3 , leading to the regioselective formation of skeletally diverse tricyclic oxo-heterocycles, in which both CBrCl 3 and H 2 O are the source of the lactone (Scheme 1b).…”

Direct Access to Strained Fused Dihalo-Aziridino Quinoxalinones via C3-Alkylation Followed by Tandem Cyclization

“…To utilize this product for further applications, we planned to explore the reactivity of 3aa under visible light reaction conditions. As our research group has been actively working in the area of photoredox catalysis, we explored the chemoselective and regioselective reduction of 3aa in the presence of DIPEA in acetonitrile under visible light conditions to afford the corresponding mono-debrominated product 4b in very good yield (79%) (Scheme ). Alongside, we have also carried out the reduction of the amide group of 3aa using DIBAL-H in THF at −78 °C to afford the corresponding useful fused dibromo-aziridino piperazine derivative 4a in good yield (71%, Scheme ).…”

Eosin Y mediated photo-catalytic C–H functionalization: C–C and C–S bond formation

“…Various electron-donating, withdrawing, and deactivating groups showed compatibility with the employed protocol and gave the final products in good yields (Scheme 90). 84 The authors also performed various control experiments such as cyclic voltammetry and Stern–Volmer constant calculation to gain mechanistic insight and concluded the free radical pathway via SET oxidation.…”