A highly efficient and generally applicable iodine-catalyzed reaction of arylacetylenic acids and arylacetylenes with sodiumsulfinates for the synthesis of arylacetylenic sulfones was developed. The methodology has the advantages of a metal-free strategy, easy to handle reagents, functional group tolerance, a wide range of arylacetylenic acids and arylacetylenes, and easy access to arylacetylenic
Mukaiyama reagent-promoted metal-free preparation of alkynyl sulfones and phosphonates under mild conditions
作者:Danyang Qi、Wanrong Dong、Zhihong Peng、Yingjun Zhang、Delie An
DOI:10.1016/j.tet.2019.06.035
日期:2019.8
An efficient and mild route for the formation sulfur or phosphor-substituted alkynes was herein demonstrated. The Mukaiyama reagent-mediated transformation started from easily-accessible substrates without carbon-carbon triple bonds, and the reaction proceeded undermildconditions (room temperature) in a one-pot manner, requiring for no transition metal-catalysts. The practical protocol featured for
SOMOphilic Alkynylation of Unreactive Alkenes Enabled by Iron-Catalyzed Hydrogen Atom Transfer
作者:Binlin Zhao、Tianxiang Zhu、Mengtao Ma、Zhuangzhi Shi
DOI:10.3390/molecules27010033
日期:——
We report an efficient and practical iron-catalyzed hydrogen atom transfer protocol for assembling acetylenic motifs into functional alkenes. Diversities of internal alkynes could be obtained from readily available alkenes and acetylenic sulfones with excellent Markovnikov selectivity. An iron hydride hydrogen atom transfer catalytic cycle was described to clarify the mechanism of this reaction.
Visible Light-Induced Reductive Alkynylation of Aldehydes by Umpolung Approach
作者:Ibuki Tanaka、Masaya Sawamura、Yohei Shimizu
DOI:10.1021/acs.orglett.1c03927
日期:2022.1.21
irradiation. Ketyl radicals, generated by single-electron reduction of aldehydes through proton-coupled electron transfer (PCET), reacted with electrophilic alkynylsulfones. Sterically demanding bulky aldehydes reacted smoothly under the Umpolung reaction conditions. Moreover, the alkynylation proceeded chemoselectively with an aryl aldehyde group in the presence of other carbonylgroups including an aliphatic
通过 Umpolung 方法对醛进行还原性炔基化是在蓝色 LED 照射下使用光氧化还原催化剂开发的。通过质子耦合电子转移 (PCET) 醛的单电子还原产生的酮基自由基与亲电子炔基砜反应。空间要求高的大体积醛在 Umpolung 反应条件下反应平稳。此外,在包括脂肪族醛基在内的其他羰基存在下,炔基化与芳基醛基化学选择性地进行。
Gold‐Catalyzed Oxygen Transfer to Alkynylsulfones: A Diazo‐Free Route to 4‐Sulfonyl‐1,3‐Oxazoles
作者:Elena I. Chikunova、Dmitry V. Dar'in、Vadim Yu. Kukushkin、Alexey Yu. Dubovtsev
DOI:10.1002/adsc.202200751
日期:2022.11.8
The gold-catalyzed annulation of alkynylsulfones, involving pyridine N-oxides (as O-atom transfer reagents) and nitriles (as C=N synthons), comprises a diazo-free route to valuable 4-sulfonyl-1,3-oxazoles. This reaction operates under relatively mild conditions (IPrAuNTf2 5 mol %, rt or 60 °C), and a number of functionalities was compatible (35 examples; 14–95%). In most cases, the SO2 fragment, which
炔基砜的金催化环化,包括吡啶N-氧化物(作为O原子转移试剂)和腈(作为 C=N 合成子),包括生成有价值的 4-磺酰基-1,3-恶唑的无重氮途径。该反应在相对温和的条件下进行(IPrAuNTf 2 5 mol%,rt 或 60 °C),并且许多功能是兼容的(35 个示例;14-95%)。在大多数情况下,通常在先前报道的 Au 催化的O转移到炔基砜中排出的 SO 2片段保留在杂环产物中。假定的反应机制表明通过O原子转移形成的反应性金 α-氧代卡宾中间体的关键作用。