An efficient and generally applicable protocol for decarboxylative coupling of α,α‐difluoroarylacetic acids with ethynylbenziodoxolone (EBX) reagents has been developed, affording α,α‐difluoromethylated alkynes bearing various functional groups in moderate to excellent yields. Remarkably, this potassium persulfate (K2S2O8)‐promoted reaction employs water as solvent under transition metal‐free conditions
已经开发出一种有效且普遍适用的方案,用于将α,α-二氟代芳酸与乙炔基苯并恶唑酮(EBX)试剂进行脱羧偶联,从而以中等至极好的收率提供带有各种官能团的α,α-二氟甲基化炔烃。值得注意的是,这种过硫酸钾(K 2 S 2 O 8)促进的反应在无过渡金属的条件下将水用作溶剂,从而为α,α-二氟甲基化炔烃提供了绿色的合成方法。
Transition-Metal-Free Synthesis of Ynones via Decarboxylative Alkynylation of α-Keto Acids under Mild Conditions
A transition-metal-free synthetic method of various ynones via decarboxylative alkynylation of α-keto acids is described. The reaction is carried out undermildconditions and exhibits remarkable tolerance of functional groups. The mechanism of a radical process is proposed in the reaction.
Decarboxylative Alkynylation of α-Keto Acids and Oxamic Acids in Aqueous Media
作者:Hua Wang、Li−Na Guo、Shun Wang、Xin-Hua Duan
DOI:10.1021/acs.orglett.5b01336
日期:2015.6.19
K2S2O8 promoted decarboxylativealkynylation of α-ketoacids and oxamic acids has been developed. This process features mild reaction conditions, a broad substrate scope, and good functional-group tolerance, therefore providing a new and efficient access to a wide range of ynones and propiolamides. Furthermore, this radical process could also be successfully applied to alkynylation of the Csp2–H bond
已经开发出温和的K 2 S 2 O 8促进α-酮酸和草酰胺酸的脱羧炔基化。该工艺具有温和的反应条件,广泛的底物范围和良好的官能团耐受性,因此提供了一种新型且有效的途径,可广泛使用炔酮和丙酰胺类化合物。此外,该自由基过程也可以成功地用于高价炔碘试剂对DMF中C sp 2 -H键的炔基化反应。
Metal-free carbonyl C(sp<sup>2</sup>)–H oxidative alkynylation of aldehydes using hypervalent iodine reagents leading to ynones
作者:Xuan-Hui Ouyang、Ren-Jie Song、Cheng-Yong Wang、Yuan Yang、Jin-Heng Li
DOI:10.1039/c5cc03362d
日期:——
The metal-free and facile synthesis of ynonesviacarbonyl C(sp2)–H oxidative alkynylation of aldehydes with enynyl benziodoxolones is presented.
As an update of our continuous interest in the hydrogenation of hydrazones, a chemo‐ and enantioselectivehydrogenation of alkynyl‐aryl hydrazones was developed using a rhodium complex [Rh((R,Sp)‐JosiPhos)(cod)]SbF6 as the catalyst and benzoic acid as an additive. Directed by a p‐nitrobenzamido group, the chiral propargyl hydrazines, which can be easily converted to chiral propargylamines of significant