Hypervalent iodine(iii)-induced oxidative [4+2] annulation of o-phenylenediamines and electron-deficient alkynes: direct synthesis of quinoxalines from alkyne substrates under metal-free conditions
Hypervalent iodine(iii)-induced oxidative [4+2] annulation of o-phenylenediamines and electron-deficient alkynes: direct synthesis of quinoxalines from alkyne substrates under metal-free conditions
Novel 8-substituted bicyclo[3.2.1]octane-6-carboxylic acids have been made via [3+2]cycloaddition to alkyne 2. A number of the corresponding amides are anti-convulsant in mice.
A heterogeneous copper-catalyzed direct oxidative cross-dehydrogenativecoupling of terminalalkynes with thiols was achieved in DMSO at 70 °C in the presence of an MCM-41-supported bidentate nitrogen copper(I) complex [MCM-41-2N-CuCl] and K2CO3 under an atmosphere of O2, yielding selectively a variety of alkynyl sulfides in good to excellent yields. This heterogeneous copper catalyst can be easily
在MSO-41负载的双齿氮铜(I)络合物[MCM-41-2N-CuCl]的存在下,在DMSO中于70°C的条件下,末端炔烃与硫醇的异质铜催化直接氧化交叉脱氢偶联反应和在O 2气氛下的K 2 CO 3,以良好至优异的产率选择性地产生各种炔基硫化物。该多相铜催化剂可通过简单的过滤容易地回收并循环10次而活性没有降低。
Two methoxycarbonylketen equivalents as dienophiles in the Diels–Alder reaction
作者:Indranil Gupta、Peter Yates
DOI:10.1039/c39820001227
日期:——
Methyl methoxypropiolate and methyl (phenylthio)propiolate give Diels–Alder adducts with 1,3-dienes; the adducts with cyclopentadienes give methyl 3-oxobicyclo[2.2.1] hept-5-ene-2-carboxylates on hydrolysis.
Gold-Catalyzed Oxidation of Thioalkynes To Form Phenylthio Ketene Derivatives via a Noncarbene Route
作者:Pankaj Sharma、Rahulkumar Rajmani Singh、Sovan Sundar Giri、Liang-Yu Chen、Mu-Jeng Cheng、Rai-Shung Liu
DOI:10.1021/acs.orglett.9b01768
日期:2019.7.19
Gold-catalyzedoxidations of thioalkynes with 8-methylquinoline oxides afford 2-phenylthioketenes that can be trapped efficiently with alcohols. The synthetic utility is manifested by terminal and internal thioalkynes over a wide scope, bearing esters, ketones, alkyl, and oxime substituents. Our density functional theory calculations suggest that gold-catalyzedoxidations of terminal and internal thioalkynes
Relative Rates of Metal-Free Azide–Alkyne Cycloadditions: Tunability over 3 Orders of Magnitude
作者:Patrick W. Skelly、Jirapon Sae-Jew、Ana Paula Kitos Vasconcelos、Jerin Tasnim、Longbo Li、Jevgenij A. Raskatov、Rebecca Braslau
DOI:10.1021/acs.joc.9b01887
日期:2019.11.1
The thermal (3 + 2) dipolar azide-alkyne cycloaddition, proceeding without copper or strained alkynes, is an underutilized ligation with potential applications in materials, bioorganic, and synthetic chemistry. Herein, we investigate the effects of alkyne substitution on the rate of this reaction, both experimentally and computationally. Electron-withdrawing groups accelerate the reaction, providing