Ruthenium PNP pincer complexes bearing supplementary cyclometalated C,N-bound ligands have been prepared and fully characterized for the first time. By replacing CO and H- as ancillary ligands in such complexes, additional electronic and steric modifications of this topical class of catalysts are possible. The advantages of the new catalysts are demonstrated in the general α-alkylation of ketones with
Cobalt-Catalyzed Enantioconvergent Hydrogenation of Minimally Functionalized Isomeric Olefins
作者:Peng Lu、Hongliang Wang、Yihui Mao、Xin Hong、Zhan Lu
DOI:10.1021/jacs.2c08525
日期:2022.9.28
established methods often require geometrically pure olefins. The enantioconvergent reaction provided the possibility to access a single stereoisomer via hydrogenation of E/Z-olefin mixtures; however, a polar functional group next to the carbon–carbon double bond was usually necessary. Here, we reported a cobalt-catalyzed enantioconvergent hydrogenation of readily available minimally functionalized E/Z-olefin
由于对映体纯化合物的高需求,烯烃不对称氢化的研究在药物分子合成和化学工业中都具有重要意义。已建立的方法通常需要几何纯烯烃。对映收敛反应提供了通过氢化E / Z -烯烃混合物获得单一立体异构体的可能性;然而,通常需要在碳-碳双键旁边的极性官能团。在这里,我们报道了一种钴催化的对映收敛氢化容易获得的最小官能化E / Z-烯烃混合物。该策略显示出良好的官能团耐受性,并为对映收敛转化提供了一种替代方法。初步机理研究表明,钴催化异构化是实现收敛转化的关键。
Selective nickel-electrocatalyzed benzylic C–H oxygenation of functionalized alkyl arenes
provides a safe, green and economical method for oxidation of a range of molecules varying in complexity and drug derivatives, demonstrating its potential application in organic synthesis and the pharmaceutical industry. Reaction outcomes and mechanistic studies revealed the key role of the in situ Ni(II)-dioxygen species for the subsequent oxidation of C(sp3)–H bonds, and short-lived reactive intermediates
A photoinduced nickel-catalyzed reductive carbonylative coupling from organohalides and N-(acyloxy)phthalimide esters with phenyl formate as the carbonyl source has been developed. This reaction could perform smoothly under mild conditions, and a series of aryl–alkyl and alkyl–alkyl unsymmetrical ketones were produced without the need of stoichiometric metal reductants. Mechanistic studies indicate
Catalytic Ring-Opening of Cyclic Alcohols Enabled by PCET Activation of Strong O–H Bonds
作者:Hatice G. Yayla、Huaiju Wang、Kyle T. Tarantino、Hudson S. Orbe、Robert R. Knowles
DOI:10.1021/jacs.6b06517
日期:2016.8.31
the redox-neutral isomerization of cyclic alcohols to linear ketones via C-C bond scission. Mechanistic studies demonstrate that key alkoxy radical intermediates in this reaction are generated via the direct homolytic activation of alcohol O-H bonds in an unusual intramolecular PCET process, wherein the electron travels to a proximal radical cation in concert with proton transfer to a weak Brønsted base
我们报告了一种新的光催化协议,用于通过 CC 键断裂将环醇氧化还原中性异构化为线性酮。机理研究表明,该反应中的关键烷氧基自由基中间体是通过在不寻常的分子内 PCET 过程中通过醇 OH 键的直接均裂活化而产生的,其中电子传播到邻近的自由基阳离子,同时质子转移到弱的布朗斯台德碱。显示有效的键强度考虑因素可以准确预测使用给定氧化剂/碱基对生成烷氧基自由基的可行性。