title: Visible-Light-Promoted [2 + 2 + 2] Cyclization of Alkynes with Nitriles to Pyridines Using Pyrylium Salts as Photoredox Catalysts.
abstract: A highly regioselective [2 + 2 + 2] cyclization of aromatic alkynes with nitriles is developed for the preparation of 2,3,6-trisubstituted pyridines under visible-light irradiation using a pyrylium salt as the photoredox catalyst. This cycloaddition is achieved through a photooxidative single-electron-transfer process at room temperature and under metal-free conditions. A variety of aromatic alkynes and nitriles are employed to furnish the annulation products in good yields.
authors.affiliation: Department of Chemistry, Huaibei Normal University , Huaibei, Anhui 235000, P.R. China.
authors.forename: Kuai
authors.initials: K
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Huaibei Normal University , Huaibei, Anhui 235000, P.R. China.
authors.forename: Ling-Guo
authors.initials: LG
authors.lastname: Meng
authors.affiliation: Department of Chemistry, Huaibei Normal University , Huaibei, Anhui 235000, P.R. China.|State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry , Shanghai 200032, P.R. China.
authors.forename: Lei
authors.identifier: 0000-0001-6580-7671
authors.initials: L
authors.lastname: Wang