在弱酸性条件下,在与终端炔烃相当的时间和温度(≤95°C)下,通过三键的正式水合,烷基芳基炔烃具有完全的区域选择性,从而转化为相应的芳基酮。Fe 2(SO 4)3 n H 2催化的过程冰乙酸中的O具有良好的官能团相容性,包括具有庞大的三键取代基的官能团相容性,并且可以通过去甲硅烷基化水合序列扩展为芳基三甲基甲硅烷基乙炔一锅转化为乙酰基衍生物的过程。总体反应模式以及质子亲和力数据表明,三键是通过质子转移而不是通过与金属离子的π相互作用激活的。该机理特征与贵金属催化剂的机理不同,解释了Fe 2(SO 4)3 n H 2 O / AcOH催化体系表现出的总区域选择性和对空间位阻的不敏感性。
Triflic acid catalysed regioselective synthesis of substituted naphthalenes by benzannulation of carbonyls with alkynes
作者:Vanajakshi Gudla、Mokhamatam Sudheer、Chinthu Joginarayana Rao、Paul Douglas Sanasi、Venkateswara Rao Battula
DOI:10.1016/j.tet.2021.132214
日期:2021.6
An interesting and facile triflic acid catalysed annulation of α-aryl carbonyls with arylalkynes is presented for the regioselective synthesis of substitutednaphthalenes. The annulation reaction involves a sequence of electrophilic attack of carbonyl on arylalkyne and benzannulation catalysed by triflic acid. The present catalyst effects this transformation at room temperature itself. Intramolecular
Direct use of nanoparticles as a heterogeneous catalyst: Pd0-doped CoFe2O4 magnetic nanoparticles for Sonogashira coupling reaction
作者:Subhasish Roy、Kula Kamal Senapati、Prodeep Phukan
DOI:10.1007/s11164-014-1699-1
日期:2015.8
A magneticallyseparable nanocatalyst prepared by incorporating Pd nanoparticles onto CoFe2O4 magneticnanoparticles was found to be very effective in catalyzing Sonogashira cross-coupling reactions. In this green synthetic process, it is not necessary to use an external linker to support the palladium nanoparticles onto the cobalt ferrite matrix. The catalyst is effective without the use of any ligand
发现通过将Pd纳米颗粒掺入CoFe 2 O 4磁性纳米颗粒制备的可磁分离的纳米催化剂在催化Sonogashira交叉偶联反应中非常有效。在这种绿色的合成过程中,无需使用外部连接器将钯纳米颗粒负载到钴铁氧体基质上。该催化剂在不使用任何配体或铜添加剂的情况下是有效的。该反应可在70°C的乙醇中与芳基碘化物和溴化物一起顺利进行,从而以高收率生产相应的产物。反应完成后,可以使用外部磁体轻松分离催化剂,并重复使用多达五个具有持续催化活性的催化循环。