NBS-mediated C-selenocyanation/cyclization of enaminones with KSeCN: a mild and efficient synthesis of 2-aminoselenazoles

Abstract

A simple, exogenous-base-free, and NBS-mediated C-selenocyanation/cyclization reaction of enaminones with KSeCN under mild conditions has been developed, providing a facile synthetic route to 2-aminoselenazole products. This efficient protocol is postulated to proceed via an initial NBS-oxidated polarity reversal of the reactive SeCN⁻ anion to form N-selenocyanosuccinimide as an electrophilic selenium source, which can induce the C-selenocyanation of enaminones and enamino esters, followed by a nucleophilic cyclization promoted by the in situ generated HBr.