A convenient base-mediated synthesis of 3-aryol-4-methyl (or benzyl)-2-methylthio furans from α-oxo ketene dithioacetals and propargyl alcohols via domino coupling/annulations
S-functionalized internal olefins, that is, α-oxo ketene dithioacetals, was efficiently achieved with alcohols as the alkoxylating agents, (diacetoxyiodo)benzene (PhI(OAc)2) as the oxidant, and benzoquinone (BQ) as the co-oxidant. The alkoxylated olefins were thus constructed and applied for the synthesis of alkoxylated N-heterocycles. Polarization of the olefinic carbon-carbon doublebond by the electron-donating
S-acetals) under mild conditions. Simple treatment of such enaminones with PhI(OAc)2 at ambient temperature in air afforded diverse multiply functionalized α,β-unsaturatedamides including β-cyclopropylated acrylamides, in which a wide array of functional groups such as aryl, (hetero)aryl, alkenyl, and alkyl can be conveniently introduced to a ketene moiety. The reaction mechanism was investigated by exploring
Photoredox-Catalyzed C–H Arylation of Internal Alkenes to Tetrasubstituted Alkenes: Synthesis of Tamoxifen
作者:Quannan Wang、Xiaoge Yang、Ping Wu、Zhengkun Yu
DOI:10.1021/acs.orglett.7b03223
日期:2017.11.17
Visible-light-induced direct C–H arylation of S,S-functionalized internal alkenes, that is, α-oxo ketene dithioacetals and analogues, has been efficiently realized with aryldiazonium salts (ArN2BF4) as coupling partners and Ru(bpy)3Cl2·6H2O as photosensitizer at ambient temperature. The strategy to activate the internal olefinic C–H bond by both the alkylthio and electron-withdrawing functional groups
Copper-Catalyzed Formal Carbene Migratory Insertion into Internal Olefinic C═C Bonds with <i>N</i>-Tosylhydrazones To Access Iminofuran and 2(3<i>H</i>)-Furanone Derivatives
α-oxo ketene N,S-acetals, has been achieved by means of N-tosylhydrazones of ketones as the carbene precursors. Iminofuran derivatives were obtained and further transformed to the corresponding 2(3H)-furanones and 4-oxobutanoates (γ-ketoesters), respectively, under mild conditions. In a similar fashion, α-thioxo ketene N,S-acetals reacted with N-tosylhydrazones of ketones to afford iminothiophenes. It
PhIO-Mediated Oxidative C═C Bond Cleavage and Reassembly toward Highly Functionalized Oxazolones
作者:Zhuqing Liu、Shaobin Sun、Jiang Lou
DOI:10.1021/acs.orglett.1c04326
日期:2022.2.18
An efficient PhIO-mediated oxidative C═Cbondcleavage and reassembly of enaminone toward oxazolone with high regioselectivity has been reported. DFT calculations revealed that the reaction proceeded through an oxygen atom transfer, C═Cbondcleavage, alkylthio migration, and reassembly cascade. This strategy is highlighted by high atom and step economy with formation of five bonds in one pot and generation