available ketones. Mechanistic studies suggest that this Rh-catalyzed deoxygenative borylation of ketones goes through an alkene intermediate, which undergoes regiodivergent hydroboration to afford linear and branched alkylboronates. The different steric effects of PPh2Me and P(nBu)3 were found to be responsible for product selectivity by density functional theory calculations. The alkene intermediate
在这里,我们报告了一种有效的铑催化酮脱氧硼酸化合成烷基硼酸酯,其中区域选择性可以通过选择配体来切换。直链烷基硼酸酯仅在 P( n Bu) 3存在下获得,PPh 2 Me 有利于支链烷基硼酸酯的形成。该协议还允许从现成的酮中获取 1,1,2-三硼酸酯。机理研究表明,这种 Rh 催化的酮类脱氧硼酸化反应经过烯烃中间体,该中间体经历区域发散硼氢化反应,得到直链和支链烷基硼酸酯。PPh 2 Me 和 P( n Bu) 3的不同空间位阻效应通过密度泛函理论计算发现是产物选择性的原因。烯烃中间体也可以依次进行脱氢硼酸化和硼氢化反应以提供三硼酸酯。
Iron-Catalyzed, Markovnikov-Selective Hydroboration of Styrenes
作者:Xu Chen、Zhaoyang Cheng、Zhan Lu
DOI:10.1021/acs.orglett.7b00227
日期:2017.3.3
A highly Markovnikov-selective, iron-catalyzed hydroboration of styrenes is reported using available oxazolinylphenyl picolinamide as the ligand to afford the branched hydroboration products with up to >50/1 b/l. This reaction is operationally simple and could be carried out in gram scale.
据报道,使用可用的恶唑啉基苯基吡啶甲酸酰胺作为配体,对苯乙烯进行了高度马尔科夫尼科夫选择性铁催化的硼氢化反应,以提供最高> 50/1 b / l的支链硼氢化产物。该反应操作简单,可以以克为单位进行。
Cobalt-Catalyzed Hydroboration of Alkenes, Aldehydes, and Ketones
作者:Sem Raj Tamang、Deepika Bedi、Sara Shafiei-Haghighi、Cecilia R. Smith、Christian Crawford、Michael Findlater
DOI:10.1021/acs.orglett.8b02775
日期:2018.11.2
An operationally convenient and general method for hydroboration of alkenes, aldehydes, and ketones employing Co(acac)3 as a precatalyst is reported. The hydroboration of alkenes in the presence of HBpin, PPh3, and NaOtBu affords good to excellent yields with high Markovnikov selectivity with up to 97:3 branched/linear selectivity. Moreover, Co(acac)3 could be used effectively to hydroborate aldehydes
报道了使用Co(acac)3作为预催化剂对烯烃,醛和酮进行氢硼化的操作方便且通用的方法。在HBpin,PPh 3和NaO t Bu存在下,烯烃进行硼氢化可提供良好的产率,并具有高的马尔可夫尼科夫选择性和高达97:3的支链/线性选择性。而且,在温和的反应条件下,在不存在添加剂的情况下,Co(acac)3可有效地用于硼氢化醛和酮。醛基的分子间和分子内化学选择性还原发生在酮官能团之上。
A Lewis Base Catalysis Approach for the Photoredox Activation of Boronic Acids and Esters
作者:Fabio Lima、Upendra K. Sharma、Lars Grunenberg、Debasmita Saha、Sandra Johannsen、Joerg Sedelmeier、Erik V. Van der Eycken、Steven V. Ley
DOI:10.1002/anie.201709690
日期:2017.11.20
either boronic acids or esters. This system enabled a wide range of alkyl boronic esters and aryl or alkyl boronic acids to react with electron-deficient olefins via radical addition to efficiently form C-C coupled products in a redox-neutral fashion. The Lewis base catalyst was shown to form a redox-active complex with either the boronic esters or the trimeric form of the boronic acids (boroxines) in
Highly Selective Hydroboration of Alkenes, Ketones and Aldehydes Catalyzed by a Well-Defined Manganese Complex
作者:Guoqi Zhang、Haisu Zeng、Jing Wu、Zhiwei Yin、Shengping Zheng、James C. Fettinger
DOI:10.1002/anie.201607579
日期:2016.11.7
Well‐defined manganese complexes based on inexpensive, readily available ligands, 2,2′:6′,2′′‐terpyridine and its derivatives have been prepared and employed for the selective hydroboration of alkenes, ketones and aldehydes. Highly Markovnikov regioselective hydroboration of styrenes as well as excellent chemoselective hydroboration of ketones over alkenes were achieved, for the first time, by an earth‐abundant