Iridium-Catalyzed Intramolecular Methoxy C−H Addition to Carbon-Carbon Triple Bonds: Direct Synthesis of 3-Substituted Benzofurans from <i>o</i>
-Methoxyphenylalkynes
Catalytic hydroalkylation of an alkyne with methyl ether was accomplished. Intramolecular addition of the C−H bond of a methoxy group in 1‐methoxy‐2‐(arylethynyl)benzenes across a carbon–carbontriple bond took place efficiently either in toluene at 110 °C or in p‐xylene at 135 °C in the presence of an iridium catalyst. The initial 5‐exo cyclization products underwent double‐bond migration during the
electrophiles via Ar–C(O) cleavage remains a challenging yet highly desirable transformation in Sonogashira-type coupling. Herein, we report a palladium-catalyzed ligand-promoted alkynylation of unstrained aryl ketones. The protocol allows the alkynylation to be carried out in a one-pot procedure with broad functional-group tolerance and substrate scope. The potential applications of this protocol
PdCl<sub>2</sub>-Promoted Electrophilic Annulation of 2-Alkynylphenol Derivatives with Disulfides or Diselenides in the Presence of Iodine
作者:Hui-Ai Du、Xing-Guo Zhang、Ri-Yuan Tang、Jin-Heng Li
DOI:10.1021/jo9016309
日期:2009.10.16
of 3-chalcogen-benzo[b]furans via palladium-promoted annulation reactions of 2-alkynylphenol derivatives with disulfides or diselenides and iodide has been developed. In the presence of I2 and PdCl2, both 3-sulfenylbenzofurans and 3-selenenylbenzofurans were selectively prepared from the cyclization of 2-alkynyanisoles with disulfides or diselenides in moderate to excellent yields.
通过2-炔基苯酚衍生物与二硫化物或二硒化物和碘化物的钯促进的环化反应,已开发出有效合成3-硫属元素-苯并[ b ]呋喃的方法。在I 2和PdCl 2的存在下,由2-炔基吲哚与二硫化物或二硒化物的环化反应选择性地制备了3-亚磺酰基苯并呋喃和3-硒烯苯并呋喃,且产率中等至优异。
Synthesis of
<scp>3‐Methylthio</scp>
‐benzo[
<i>b</i>
]furans/Thiophenes
<i>via</i>
Intramolecular Cyclization of
<scp>2‐Alkynylanisoles</scp>
/Sulfides Mediated by
<scp>DMSO</scp>
/
<scp>DMSO</scp>
‐
<i>d</i>
<sub>6</sub>
and
<scp>
SOCl
<sub>2</sub>
</scp>
作者:Beibei Zhang、Xiaoxian Li、Xuemin Li、Fengxia Sun、Yunfei Du
DOI:10.1002/cjoc.202000566
日期:2021.4
with SOCl2 and DMSO was conducted to conveniently furnish the biologically interesting 3‐(methylthio)‐benzo[b]furans/thiophenes via intramolecularcyclization. DMSO acts as a solvent as well as a sulfur source and can also be replaced with DMSO‐d6, enabling the incorporation of the SCD3 moiety of DMSO‐d6 to the 3‐position of the heterocyclic frameworks.
进行2-炔基苯甲醚/硫化物与SOCl 2和DMSO的反应以通过分子内环化方便地提供生物学上令人感兴趣的3-(甲硫基)-苯并[ b ]呋喃/噻吩。DMSO充当溶剂,以及作为硫源,也可以用替换DMSO- d 6,使SCD的掺入3 DMSO-的部分d 6到杂环框架的3位上。
Electrophilic Selenocyanogen Cyclization of Alkynes; Synthesis of Benzofurylselenocyanates, Benzothienylselenocyanates and Indolylselenocyanates
A method to synthesize benzofurylselenocyanates, benzothienylselenocyanates and indolylselenocyanates via electrophilic selenocyanogen cyclization was established. This sequential process was conducted under mild conditions in a short time. This protocol was successfully applied to late-stage functionalization of bioactive molecules. Notablely, the selenocyanate can be converted into other valuable