title: Transformation of reactive isochromenylium intermediates to stable salts and their cascade reactions with olefins.
abstract: Transformation of reactive isochromenylium intermediates to the corresponding storable and stable reagents has been achieved, and a number of isochromenylium tetrafluoroborates (ICTBs, 1) have been conveniently prepared and characterized. Direct metal-free treatment of isochromenylium tetrafluoroborate 1a with olefins afforded a variety of polycyclic frameworks 4 via mild cascade reactions. Starting from the prefunctionalized o-alkynylbenzaldehydes, a one-pot metal-free procedure of intramolecular cascade annulation to 2,3-dihydrophenanthren-4(1H)-one derivatives was also developed.
authors.affiliation: State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China.
authors.forename: Zhi-Long
authors.initials: ZL
authors.lastname: Hu
authors.forename: Wen-Jian
authors.initials: WJ
authors.lastname: Qian
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Shaozhong
authors.initials: S
authors.lastname: Wang
authors.forename: Zhu-Jun
authors.initials: ZJ
authors.lastname: Yao
mesh_terms: D000388:Air; D000475:Alkenes / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D012492:Salts / Q000737:chemistry*
chemical_list: D000475:Alkenes; D012492:Salts