title: A novel synthesis of benzo[b]selenophenes via regioselective intramolecular transformation of 4-(3-nitroaryl)-1,2,3-selenadiazoles.
abstract: 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, S(N)Ar(H)) pathway, by oxidative aromatization of the rapidly formed σ(H)-adduct, takes place. In the absence of oxidant, the reaction proceeds via intermediate formation of the σ(Cl)-adduct, following nucleophilic aromatic substitution of the halogen (S(N)Ar(Cl)) pathway.
authors.affiliation: Department of Organic Chemistry, Saint-Petersburg State Institute of Technology, Moskovskii prospekt 26, Saint-Petersburg 190013, Russia.
authors.forename: Anna G
authors.initials: AG
authors.lastname: Lyapunova
authors.forename: Mikhail L
authors.initials: ML
authors.lastname: Petrov
authors.forename: Dmitry A
authors.initials: DA
authors.lastname: Androsov