不饱和16E -片段[(C 5我5)的Rh(PME 3)]已观察到插入硫-碳键中的各种取代的二苯并噻吩,得到一个六元金属环产物。通过改变二苯并噻吩上取代基的位置和性质来探究CS插入的区域选择性,发现选择性受空间位阻的支配,且电子贡献较小。在4-甲基二苯并噻吩,2,6-二甲基二苯并噻吩和苯并[ b ]萘[2,1- d ]中发现仅插入空间受阻较小的CS键]噻吩。向未取代的环的插入是具有2-氟二苯并噻吩和2-甲氧基二苯并噻吩的两个CS插入异构体的主要产物。观察到2-(三氟甲基)二苯并噻吩和2-氰基二苯并噻吩向取代环的插入是有利的。在2-甲基二苯并噻吩,3-甲基二苯并噻吩,2,8-二甲基二苯并噻吩,1,3,7-三甲基二苯并噻吩和苯并[ b ]萘[1,2- d]噻吩。2-溴二苯并噻吩显示了C-Br激活以及两个CS插入产物(2:1),而2-碘二苯并噻吩仅显示了C-I激活。4,6-二甲基形成的不稳定的S
Nickel‐Mediated Trifluoromethylation of Phenol Derivatives by Aryl C−O Bond Activation
作者:Wei‐Qiang Hu、Shen Pan、Xiu‐Hua Xu、David A. Vicic、Feng‐Ling Qing
DOI:10.1002/anie.202004116
日期:2020.9.7
trifluoromethylation reactions. Tremendous efforts have focused on copper‐ and palladium‐mediated/catalyzed trifluoromethylation of aryl halides. In contrast, no general method exists for the conversion of widely available inert electrophiles, such as phenol derivatives, into the corresponding trifluoromethylated arenes. Reported herein is a practical nickel‐mediated trifluoromethylation of phenol derivatives with readily
Phosphovanadomolybdic acid catalyzed direct C–H trifluoromethylation of (hetero)arenes using NaSO<sub>2</sub>CF<sub>3</sub> as the CF<sub>3</sub> source and O<sub>2</sub> as the terminal oxidant
A direct C–H trifluoromethylation of (hetero)arenesusing NaSO2CF3 (Langlois' reagent) as the CF3 source and O2 as the terminal oxidant has been developed. In the presence of catalytic amounts of phosphovanadomolybdic acids, such as H6PV3Mo9O40, various kinds of substituted benzenes and heteroaromatic compounds could be converted into the corresponding trifluoromethylated products.
已经开发了使用NaSO 2 CF 3(Langlois试剂)作为CF 3源和O 2作为末端氧化剂对(杂)芳烃进行直接C–H三氟甲基化。在催化量的磷钒钼酸如H 6 PV 3 Mo 9 O 40的存在下,各种取代的苯和杂芳族化合物可以转化为相应的三氟甲基化产物。
Catalyst-free, direct synthesis of dibenzothiophenes
作者:Kim Christopher C. Aganda、Sangcheol Na、Anna Lee
DOI:10.1016/j.tetlet.2022.154009
日期:2022.8
A catalyst-free method for the synthesis of dibenzothiophenes has been developed. The nucleophilic intramolecular cyclization of methylthiolated diazonium salts enables the direct synthesis of dibenzothiophenes under mild reaction conditions. The addition of TEMPO is beneficial for improving the reaction yield by suppressing the formation of by-products, which can be formed via a radical-mediated process
已经开发了一种用于合成二苯并噻吩的无催化剂方法。甲基硫醇化重氮盐的亲核分子内环化能够在温和的反应条件下直接合成二苯并噻吩。添加 TEMPO 有利于通过抑制副产物的形成来提高反应产率,副产物可以通过自由基介导的过程形成。这种简单的方法为合成二苯并噻吩提供了一种替代方法,二苯并噻吩经常存在于有价值的化合物中。
Direct C–H Trifluoromethylation of Glycals by Photoredox Catalysis
作者:Bang Wang、De-Cai Xiong、Xin-Shan Ye
DOI:10.1021/acs.orglett.5b03016
日期:2015.11.20
A Mild, efficient, and practical transformation for the direct C-H,trifluotoni-ethylation:of glycals under visible light has been reported for the first time This reaction employed fac-Ir3+ (ppy)(3) as the photocatalyst) Urnemo's reagent as the CF3 source, and a household blue Letp or sunlight as the light source. Glycals bearing both withdrawing and -donating protective groups performed this reaction smoothly: This visible ligilit-mediated trifluomethylation reaction was highlighted by the trifluoromethlyation of the biologically important Neu2en moiety.