芳基和烷基 β-杂原子三取代乙烯基三氟乙烯与四氢呋喃和环己烷反应,进行三氟甲基自由基介导的 CH 官能化反应,得到 E 和 Z β-杂原子三取代烯烃。大多数反应以高产率和高立体特异性(构型保留)进行。本研究中使用的β-取代基是碘、溴、氟、苯甲酸酯、碳酸乙酯和邻苯二甲酰亚胺。带有强大电子释放基团(如烷氧基或氨基)的 β-取代基使乙烯基三氟乙烯失去反应性。
A novel, efficient Z-alkene synthesis via photocatalyzed decarboxylative couplings between terminal aryl alkynes and alkyl N-hydroxyphthalimide (NHPI) esters, which are derived from aliphatic carboxylic acids, is described. A wide range of primary, secondary, and tertiary carboxylates as well as α-amino acid and α-oxyacid-derived esters were employed as suitable substrates. The mild reaction conditions
NiCl2-catalyzed radical cross decarboxylative coupling between arylpropiolic acids and cyclic ethers
作者:Zi-juan Wan、Jin-yuan Wang、Jun Luo
DOI:10.1016/j.tetlet.2019.01.039
日期:2019.2
A direct alkenylation of cyclic ethers via radical cross decarboxylative coupling process catalyzed by NiCl2 and using DTBP as radicalinitiator and oxidant was developed. A variety of arylpropiolic acids and cyclic ethers were transformed into the corresponding 2-arylvinyl cyclic ethers in moderate to excellent yields. Mechanistic experiments were conducted to determine the nature of the reaction
KOAc-promoted alkynylation of α-C–H bonds of ethers with alkynyl bromides under transition-metal-free conditions
作者:Jiajun Zhang、Pinhua Li、Lei Wang
DOI:10.1039/c4ob00002a
日期:——
KOAc-promoted α-position C–H activation and alkynylation of ethers with alkynyl bromides to 2-alkynyl ethers was developed under transition-metal-free conditions.
Visible Light‐Enabled sp
<sup>3</sup>
‐C−H Functionalization with Chloro‐ and Bromoalkynes: Chemoselective Route to Vinylchlorides or Alkynes
作者:Tapas Adak、Marvin Hoffmann、Sina Witzel、Matthias Rudolph、Andreas Dreuw、A. Stephen K. Hashmi
DOI:10.1002/chem.202001259
日期:2020.12
valuable vinyl chlorides. The photo‐organocatalytic hydrogen atom transfer strategy gives rise to a broad range of diversely functionalized olefins. When bromoalkynes are applied in the presence of a base, a chemoselectivity switch to an alkynylation is observed. This reaction can even be performed for the alkynylation of unactivated sp3‐C−H bonds, in this case with a preference of the more substituted
实现了氯炔的前所未有的直接原子经济化学和区域选择性加氢烷基化和溴炔的 sp 3 -C-H 炔基化。反应伙伴是未官能化的醚、醇、酰胺,甚至未活化的烃。我们发现家用荧光灯能够激发二芳基酮,然后二芳基酮选择性地从 sp 3 ‐C−H 键中提取 H 原子。用氯炔获得正式炔插入 sp 3 ‐C−H 键的产物,从而提供有价值的氯乙烯。光有机催化氢原子转移策略产生了多种不同官能化的烯烃。当在碱存在下应用溴代炔时,观察到化学选择性转变为炔基化。该反应甚至可以用于未活化的 sp 3 -C-H 键的炔基化,在这种情况下优选取代更多的碳。伴随的量子化学计算表明乙烯基自由基中间体与碳自由基中心具有明显的线性配位,从而能够在H原子抽象后形成两种非对映异构体,表明( Z )-非对映异构体是优选的,这支持了实验观察到的( E / Z )‐分布。