An aryne triggered ring-opening fluorination of cyclic thioethers with potassium fluoride
作者:Rong Fan、Binbin Liu、Tianyu Zheng、Kun Xu、Chen Tan、Tianlong Zeng、Shuaisong Su、Jiajing Tan
DOI:10.1039/c8cc03766c
日期:——
report an aryne triggered ring-opening fluorination protocol of a great variety of saturated sulfur heterocycles. A key factor for the success is the identification of a suitable mediator. Compared to previous methods, this transition-metal free protocol employs low-cost potassium fluoride as the fluorine source. The operational simplicity and mild reaction conditions allow for the rapid synthesis of a
Organosulfides are a common class of structure units in bioactive molecules and functional materials motivating continuous developments of efficient synthetic methods. Herein, we report an electrophilic aryne-activated ringopening protocol of one or two heteroatom containing saturated sulfur heterocycles. This three-component transformation proceeds under mild reaction conditions and displays exceptional
The selenium-containing dinuclear peroxotungstate, [(n-C4H9)4N]2[SeO4WO(O2)2}2] (I), acts as a homogeneous catalyst for the selective oxidation of various kinds of cyclic mono- and disulfides with 30% aqueous H2O2. The cyclic disulfides were selectively oxidized to the corresponding monosulfoxides with one equivalent of H2O2 with respect to the sulfides. In the presence of two equivalents of H2O2, the oxidation of dibenzothiophene gave the corresponding sulfone in 98% yield under the mild conditions. The negative Hammett Ï value (â0.62) for the competitive oxidation of p-substituted thioanisoles and the low XSO (XSO = (nucleophilic oxidation)/(total oxidation)) value of 0.14 for the I-catalyzed oxidation of thianthrene 5-oxide (SSO) revealed that I is a strong electrophilic oxidant. The reactivities of the di- and tetranuclear peroxotungstates with XO4nâ ligands (X = Se(VI), As(V), P(V), S(VI), and Si(IV)) were strongly dependent on the kinds of hetero atoms. The reaction rates for the sulfoxidation decreased with an increase in the XSO values and a peroxotungstate with a stronger electrophilicity was more active for the sulfoxidation. The kinetic and mechanistic investigations showed that the electrophilic attack of the peroxo oxygen at the sulfur atom is a key step in the sulfoxidation. The computational investigation supported the high chemoselectivitiy for the sulfoxidation of diallyl sulfide.
Divergent synthesis of functionalized thioethers via multicomponent reaction of benzynes
作者:Hui Jian、Qiang Wang、Wei-Hua Wang、Zhi-Juan Li、Cheng-Zhi Gu、Bin Dai、Lin He
DOI:10.1016/j.tet.2018.04.072
日期:2018.6
Diverse functionalized thioethers were efficiently synthesized through the multicomponent reaction of benzynes, cyclic thioethers and different nucleophiles. Both inorganic salts (KF, KCl, KBr, and KSCN) and silylated reagents (TMSCN, TMSN3, TMSCl) can be utilized as efficient nucleophiles for the reaction.
Regioselective Reaction of Heterocyclic <i>N</i>-Oxides, an Acyl Chloride, and Cyclic Thioethers
作者:Przemyslaw Frei、D. Heulyn Jones、Steven T. Kay、Jayde A. McLellan、Blair F. Johnston、Alan R. Kennedy、Nicholas C. O. Tomkinson
DOI:10.1021/acs.joc.7b02457
日期:2018.2.2
cyclic thioether in the presence of triethylamine leads to the corresponding 2-functionalized product in up to a 74% isolated yield. The transformation can also be accomplished with alternative nitrogen containing heterocycles, including quinolines, pyrimidines, and pyrazines. To expand the scope of the transformation, diisopropyl ether can be used as the reaction medium to allow for the use of solid