TBHP‐Mediated Selenocyclization of N‐Allylbenzamides/Benzthioamides via In‐Situ Generation of "PhSeOH" Species**.

A simple tert‐butyl hydroperoxide (TBHP)‐mediated method has been developed to construct selenated oxazolines/thiazolines under microwave irradiation. The selenocyclization of N‐allylbenzamides/benzthioamides could be achieved owing to the addition of an active electrophilic selenium species, generated in situ from diphenyl diselenide on reacting with TBHP, at their olefinic site. The reaction mechanism was confirmed by intercepting and characterizing all the proposed intermediates by ESI‐QTOF‐MS and NMR study. This method offers several advantages including simpler reaction conditions, shorter reaction time, catalyst‐free, thus rendering a competent alternative to the synthesis of selenated oxazolines/thiazolines in yields of upto 95 %. [ABSTRACT FROM AUTHOR]