Synthesis of Selenaheterocycles via Visible‐Light‐Mediated Radical Cyclization

Abstract

An approach for the synthesis of selenaheterocycles starting from aryl diazonium salts was developed. The one‐pot process and subsequent visible‐light‐mediated silver‐catalyzed cyclization enabled the synthesis of selenaheterocycles in the absence of a photocatalyst. The reactions were carried out under mild conditions without the use of toxic or sensitive reagents.

Synthesis of 3‐Arylselanyl Benzothiophenes through Visible‐Light‐Mediated Radical Cyclization

“…Based on our observations and previous studies, [15,17a,23] a plausible reaction mechanism is depicted in Scheme 5. First, arylselanyl radicals are generated by the irradiation of visible light.…”

Change in the Product Selectivity in the Visible Light-Induced Selenium Radical-Mediated 1,4-Aryl Migration Process

“…In addition, the Se–Se bond energy is also quite low (172 kJ mol –1 ) . As a result, irradiating diaryldiselenide with direct visible light could facilitate the formation of the selenide radical, which can be employed in the C–Se bond formation reaction . Thus, we envisioned that unsymmetrical tetrasubstituted α,β-unsaturated carboxylic acid could be synthesized by employing a catalytic amount of organic dye under visible light irradiation.…”

Recent Advances in Light-Induced Selenylation

“…Aryldiazonium salts 10.1 were first treated with KSeCN to give the corresponding aryl selenocyanates that upon treatment with Rongalite (HOCH 2 SO 2 Na) led to diaryl diselenides. Crude diselenides were then treated with a silver catalyst in the presence of K 2 S 2 O 8 (as a sacrificial oxidant) upon visible light irradiation to form selenaheterocycles 10.2 with the intermediacy of an arylselenyl radical …”

“…Crude diselenides were then treated with a silver catalyst in the presence of K 2 S 2 O 8 (as a sacrificial oxidant) upon visible light irradiation to form selenaheterocycles 10.2 with the intermediacy of an arylselenyl radical. 57 …”