2-芳基苯并恶唑是有前途的分子,可在医学和材料领域得到潜在应用。对2-芳基苯并恶唑的直接区域选择性官能化的有效方案有很高的要求。在本文中,我们公开了通用的Cp * Rh(III)能够以高收率实现2-芳基苯并[ d ]恶唑与烯烃的选择性邻烯化的一般方法。该协议具有广泛的功能基团耐受性和高区域选择性。分子间竞争研究和动力学同位素效应实验表明,氧化烯化过程是通过亲电的C–H活化途径发生的。m的分子结构在间位F原子或杂原子取代基存在的情况下,氟取代的烯化产物可在受阻更强的位置证实区域选择性C–H活化/烯化。在单-和双-烯烃化产物的结构中观察到明显的扭转角,这导致烯烃质子的化学位移明显不同。另外,两个克级反应和进一步的转化实验表明,该方法对于合成邻链烯基化的2-芳基苯并恶唑衍生物是实用的。
Synthesis of 2-substituted pyrimidines and benzoxazoles via a visible-light-driven organocatalytic aerobic oxidation: enhancement of the reaction rate and selectivity by a base
作者:Lin Wang、Zhi-Gang Ma、Xiao-Jing Wei、Qing-Yuan Meng、Deng-Tao Yang、Shao-Fu Du、Zi-Fei Chen、Li-Zhu Wu、Qiang Liu
DOI:10.1039/c4gc00337c
日期:——
An efficient visible-light-driven photocatalytic oxidation of various 2-substituted dihydropyrimidines and phenolic imines has been achieved using an organic photocatalyst eosin Y bis(tetrabutyl ammonium salt) (TBA-eosin Y) and inexpensive oxidant molecular oxygen. With the aid of a base, significantly enhanced photoinduced electron transfer from substrates dihydropyrimidines or phenolic imines to the excited state of TBA-eosin Y has enabled the aerobic oxidation to yield 2-(methylthio)pyrimidines or 2-arylbenzoxazoles selectively.
aerobic oxidative synthesis of 2-arylbenzo[d]oxazoles, 2-substituted benzo[d]thiazoles, and 1,2-disubstituted benzo[d]imidazoles. N-Heterocyclic carbene (NHC), generated in situ from easily available N-heterocyclic imidazolium salt with air as terminal oxidant, has successfully been utilized as a cheap and efficient catalyst for one-pot aerobic oxidative synthesis of 2-arylbenzo[d]oxazoles, 2-substituted
摘要 N-杂环卡宾(NHC)是由易获得的N-杂环咪唑盐以空气为末端氧化剂原位生成的,已成功地用作便宜且有效的一锅好氧氧化合成2-芳基苯并[ d ]恶唑的催化剂,2-取代的苯并[ d ]噻唑和1,2-二取代的苯并[ d ]咪唑。 N-杂环卡宾(NHC)是由易获得的N-杂环咪唑盐以空气为末端氧化剂原位生成的,已成功地用作便宜且有效的一锅好氧氧化合成2-芳基苯并[ d ]恶唑的催化剂,2-取代的苯并[ d ]噻唑和1,2-二取代的苯并[ d ]咪唑。
Palladium-catalyzed direct arylation of benzoxazoles with unactivated simple arenes
作者:Ge Wu、Jun Zhou、Min Zhang、Peng Hu、Weiping Su
DOI:10.1039/c2cc34238c
日期:——
Using CuBr(2) as an additive, the Pd-catalyzed intermolecular C-H-C-H cross-coupling between benzoxazoles and unactivated simple arenes has been developed. This protocol provides a straightforward approach for the biological activity of 2-arylbenzoxazole derivatives.
An efficient and high yielding Cu-catalyzed direct CâH arylation of azaheterocycles including oxadiazoles, thiadiazoles, benzoxazoles and benzothiazoles has been achieved by employing easily accessible diaryliodonium salts.
TEMPO-mediated aerobic oxidative synthesis of 2-aryl benzoxazoles via ring-opening of benzoxazoles with benzylamines
作者:Mugada Sugunakara Rao、Sahid Hussain
DOI:10.1080/00397911.2021.1949476
日期:2021.9.2
Abstract A simple and efficient TEMPO-mediated system for aerobic oxidativesynthesis of 2-aryl benzoxazoles from readily available benzoxazoles and primary benzylic and hetero benzylic amines is presented in one pot. The reaction proceeds through the ring-opening of benzoxazoles and is followed by oxidative condensation with benzylamines. These metal-free, straightforward reactions worked well with a
摘要 一种简单有效的 TEMPO 介导系统,用于从容易获得的苯并恶唑和伯苄基和杂苄基胺有氧氧化合成 2-芳基苯并恶唑。该反应通过苯并恶唑的开环进行,然后与苄胺氧化缩合。这些不含金属的、直接的反应适用于各种底物,在使用空气作为外部绿色氧化剂的温和条件下产生中等至良好的产率。