An Enolate‐Structure‐Enabled Anionic Cascade Cyclization Reaction: Easy Access to Complex Scaffolds with Contiguous Six‐, Five‐, and Four‐Membered Rings
AbstractCatalyst‐free addition of ketone enolate to non‐activated multiple C−C bonds involves non‐complementary reaction partners and typically requires super‐basic conditions. On the other hand, highly aggregated or solvated enolates are not reactive enough to undergo direct addition to alkenes or alkynes. Herein, we report a new anionic cascade reaction for one‐step assembly of intriguing molecular scaffolds
Difluorocarbene-Triggered Cyclization: Synthesis of (Hetero)arene-Fused 2,2-Difluoro-2,3-dihydrothiophenes
作者:Huamin Liang、Ran Liu、Min Zhou、Yue Fu、Chuanfa Ni、Jinbo Hu
DOI:10.1021/acs.orglett.0c02688
日期:2020.9.4
An efficient method for the synthesis of (hetero)arene-fused 2,2-difluoro-2,3-dihydrothiophene derivatives using readily available sodium chlorodifluoroacetate (ClCF2CO2Na) has been developed. This transformation is achieved through a combination of a thiolate with difluorocarbene, followed by intramolecular nucleophilic addition to a ketone, cyano, or ester functional group.
已经开发了使用容易获得的氯二氟乙酸钠(ClCF 2 CO 2 Na)合成(杂)芳烃稠合的2,2-二氟-2,3-二氢噻吩衍生物的有效方法。通过硫醇盐与二氟卡宾的组合,然后向酮,氰基或酯官能团的分子内亲核加成,可以实现这种转化。
Convenient Synthesis of 3-Substituted Benzo[<i>b</i>]thiophenes by Iodine-Mediated Cyclization of α-Substituted 2-(1-Phenylethylthio)styrenes
preparation of 3-substitutedbenzo[b]thiophenes was developed. α-Substituted 2-(1-phenylethylthio)styrenes, which could easily be prepared from 2-mercaptophenyl ketones or benzenethiols in two or three steps, respectively, underwent 5-endo cyclization on treatment with iodine in the presence of sodium hydrogencarbonate in acetonitrile at room temperature to give 3-substitutedbenzo[b]thiophenes in fair to
Facile Preparation of 3-Substituted Benzisothiazoles from <i>o</i>-Mercaptoacylphenones
作者:Nelmi O. Devarie-Baez、Ming Xian
DOI:10.1021/ol9028447
日期:2010.2.19
A synthesis of 3-substituted benzisothiazoles starting from readily available o-mercaptoacylphenones is presented. The key cyclization step features a mild S-nitrosation and its succeeding intramolecular aza-Wittig reaction leading to the construction of the title compounds.
A Novel and Simple Synthesis of 2-(Trifluoromethyl)-4<i>H</i>-thiochromen-4-ones
作者:Boris I. Usachev、Vyacheslav Ya. Sosnovskikh、Mikhail A. Shafeev、Gerd-Volker Röschenthaler
DOI:10.1080/10426500590912259
日期:2005.3.2
Abstract Alkyl 2-mercaptophenyl ketones react with trifluoroacetic anhydride in the presence of triethylamine to give 2-(trifluoromethyl)-4H-thiochromen-4-ones, which are transformed into the corresponding pyrazoles by treatment with hydrazine hydrate and into 1,1-dioxides by oxidation with H2O2 in AcOH.