187147-62-2Relevant academic research and scientific papers
Copper-catalyzed oxidative cross-dehydrogenative coupling of 2H-chromenes and terminal alkynes
Yang, Fei,Li, Yangshan,Floreancig, Paul E.,Li, Xiaoyan,Liu, Lei
, p. 5144 - 5149 (2018/07/29)
An efficient copper-catalyzed cross-dehydrogenative coupling of 2H-chromenes and terminal alkynes mediated by DDQ has been established. A protic additive, EtOH, proved to be crucial for harmonizing the oxidation with a subsequent alkynylation step by retaining the oxidation state of an oxocarbenium ion in the form of acetal. The CDC reaction exhibits a good substrate scope, with a range of terminal aryl- and alkyl alkynes being well tolerated. The copper-catalyzed alkynylation of 2H-chromene acetals with terminal alkynes was also explored.
Transition-Metal-Free Cross-Coupling of Indium Organometallics with Chromene and Isochroman Acetals Mediated by BF3·OEt2
Gil-Negrete, José M.,Sestelo, José Pérez,Sarandeses, Luis A.
supporting information, p. 4316 - 4319 (2016/10/12)
A transition-metal-free coupling of triorganoindium reagents with benzopyranyl acetals mediated by a Lewis acid has been developed. The reaction of R3In with chromene and isochroman acetals in the presence of BF3·OEt2 afforded 2-substituted chromenes and 1-substituted isochromans, respectively, in good yields. The reactions proceed with a variety of triorganoindium reagents (aryl, heteroaryl, alkynyl, alkenyl, alkyl) using only 50 mol % of the organometallic, thus demonstrating the efficiency of these species. Preliminary mechanistic studies indicate the formation of an oxocarbenium ion intermediate in the presence of the Lewis acid.
Practical and highly selective C-H functionalization of structurally diverse ethers
Wan, Miao,Meng, Zhilin,Lou, Hongxiang,Liu, Lei
supporting information, p. 13845 - 13849 (2015/01/16)
A trityl ion mediated C-H functionalization of ethers with a wide range of nucleophiles at ambient temperature has been developed. The reaction displays high chemo-selectivity and good functional group tolerance. The protocol also exhibits excellent regio- and diastereoselectivities for the unsymmetric ethers, thus stereoselectively generating highly functionalized disubstituted 2,5-trans tetrahydrofurans (THF), 2,6-trans tetrahydropyrans (THP), 2,6-trans dihydropyrans (DHP), and 1,3-trans isochromans, and highlighting the capacity of the protocol in complex molecule synthesis.
Ethynyl Carbocations. VIII. Reactions of 2,4-Diphenylpyrylium and 1-Benzopyrylium Perchlorates with Lithium Phenylacetylide
Koblik,Murad'yan,Luk'yanov,Luk'yanov
, p. 887 - 892 (2007/10/03)
2,4-Diphenylpyrylium perchlorate and 1-benzopyrylium salts with no substituents in 2 and 4 positions react with lithium phenylacetylenide to form corresponding phenylethynylpyryliumsalts. In some of the reactions 1-benzopyran intermetiates appearing in these processes of nucleophilic hydrogen substitution were isolated and characterized.
