Dichalcogenides/Oxone ^® ‐Mediated Cyclization of ( <i>Z</i> )‐Chalcogenoenynes under Ultrasound Irradiation

Abstract

Abstract 3‐Selanyl‐ and 3‐tellanylchalcogenophenes were prepared by the electrophilic cyclization of ( Z )‐chalcogenoenynes under ultrasound irradiation conditions. This green procedure was carried out using Oxone ® as an inexpensive and non‐toxic oxidant agent to promote the oxidative cleavage of Se−Se and Te−Te bonds. The electrophilic cyclization of ( Z )‐1‐propylthio‐ and ( Z )‐1‐butylselen‐1‐en‐3‐ynes was performed using the diaryl diselenide or ditelluride/Oxone ® /ethanol system. The respective 3‐arylselanyl and 3‐aryltellanylthiophenes and selenophenes were obtained in 40 % to 87 % yield (16 examples). Similarly, 3‐arylselanyl and 3‐aryltellanyltellurophenes were synthesized by the cyclization of ( Z )‐1‐butyltelluro‐1‐en‐3‐ynes, using glycerol as the solvent instead ethanol (5 examples; 28 % to 65 % yield). For the first time, Oxone ® was used in the selective oxidative cleavage of the Te−Te bond in cyclization reactions.