DBU‐Mediated Synthesis of Aryl Acetylenes or 1‐Bromoethynylarenes from Aldehydes
作者:Yadagiri Thummala、Galla V. Karunakar、Venkata Ramana Doddi
DOI:10.1002/adsc.201801334
日期:2019.2
sequential manner for the synthesis of arylacetylenes and 1,3‐enynes starting directly from commercially available aldehydes. The bicyclic amidine 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) along with additive NaOH not only exclusively afforded the terminal alkynes directly from the aldehydes, but also enhanced the reaction rate. The dynamic nature of DBU also facilitated the isolation of 1‐bromoalkynes intermediate
A concise total synthesis of biologically active frutinones via tributylphosphine-catalyzed tandem acyl transfer-cyclization
作者:Masahito Yoshida、Koya Saito、Yuta Fujino、Takayuki Doi
DOI:10.1016/j.tet.2014.03.073
日期:2014.5
A concise and step-economical total synthesis of biologically active frutinones has been achieved. Tributylphosphine (PBu3) efficiently induced the tandem acyl transfer-cyclization of carbonates 5 to afford 3-methoxycarbonylflavone derivatives 4 in excellent yields. Finally, concomitant deprotection and lactonization under acidic conditions furnished the desired frutinones A (1a), B (1b), and the proposed structure of frutinone C (1c). (C) 2014 Elsevier Ltd. All rights reserved.
A Hg(OTf)<sub>2</sub>-Catalyzed Enolate Umpolung Reaction Enables the Synthesis of Coumaran-3-ones and Indolin-3-ones
作者:Zhouting Rong、Weican Hu、Ning Dai、Guoying Qian
DOI:10.1021/acs.orglett.0c01096
日期:2020.4.17
The potential of mercury catalysis has been extended to the arena of enolate umpolung reactions for the first time by the generation of enolonium species via Hg(OTf)2-catalyzed N-oxide addition to alkynes. The enolonium species formed can undergo intramolecular nucleophilic attack by hydroxyl or amino groups, leading to the synthesis of various coumaran-3-ones and indolin-3-ones.
A New Preparation of Benzofurans Utilizing Trimethylsilyldiazomethane
作者:Yasuko Ito、Toyohiko Aoyama、Takayuki Shioiri
DOI:10.1055/s-1997-999
日期:1997.10
o-Triisopropylsiloxyaryl ketones and aldehydes smoothly reacted with the lithium salt of trimethylsilyldiazomethane to give o-triisopropylsiloxyphenylacetylenes which were easily converted to benzofurans by treatment with tetra-n-butylammonium fluoride. 3-Benzofuranmethanols were also obtained when the reaction was conducted in the presence of carbonyl compounds.