A Novel Synthesis of Benzo[<i>b</i>]selenophenes via Regioselective Intramolecular Transformation of 4-(3-Nitroaryl)-1,2,3-selenadiazoles
作者:Anna G. Lyapunova、Mikhail L. Petrov、Dmitry A. Androsov
DOI:10.1021/ol400547n
日期:2013.4.5
Base-promoted transformation of 4-(3-nitroaryl)-1,2,3-selenadiazoles via intermediate formation of eneselenolates followed by 5-exo-trig cyclization Is reported. The regiochemistry of the intramolecular cyclization is condition-dependent. In the presence of an oxidant, the oxidative nucleophilic substitution of the hydrogen (ONSH, SNArH) pathway, by oxidative aromatization of the rapidly formed sigma(H)-adduct, takes place. In the absence of oxidant, the reaction proceeds via intermediate formation of the sigma(Cl)-adduct, following nucleophilic aromatic substitution of the halogen (SNArCl) pathway.