title: Direct Access to Fused Salicylaldehydes and Salicylketones from Tetraynes.
abstract: A facile method for the synthesis of fused, multifunctionalized salicylaldehydes and salicylketones by a one-pot, three-step cascade hexadehydro-Diels-Alder (HDDA) reaction of tetraynes followed by an intermolecular aldehyde/ketone reaction and hydroxylation is reported. Target compounds were prepared by the condensation of malonates with 3-bromo-1-propyne, and the resulting 2,2-di(1-propyn-3-yl)malonates underwent cross-coupling with phenylethynyl bromides to afford 2,2-di(5-phenyl-2,4-pentadiynyl)malonates, which underwent intramolecular cyclization to produce bicyclic salicylaldehydes. The overall transformation involves the formation of four new C-C bonds and one new Caryl-O bond through both intramolecular and intermolecular reactions. The reaction is easy to perform, proceeds under mild conditions, and exhibits excellent regioselectivity. Water, a simple and readily available reagent, was employed as the OH source. A plausible reaction mechanism is proposed for this new annulation based on isotopic substitution experiments.
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Functional Molecular-Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China.
authors.forename: Yimin
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Functional Molecular-Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Functional Molecular-Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Hu
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Functional Molecular-Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Ma
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Functional Molecular-Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Lv
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Functional Molecular-Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China.
authors.forename: Baohua
authors.initials: B
authors.lastname: Liu
authors.affiliation: Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Functional Molecular-Based Materials, Institute of Organic Chemistry, School of Chemistry and Materials Science, Anhui Normal University, Wuhu, Anhui, 241000, P. R. China.
authors.forename: Shaowu
authors.initials: S
authors.lastname: Wang
keywords: condensed benzenoid compounds; cross-coupling; cyclization; hexadehydro-Diels-Alder reaction; salicylaldehyde derivatives