Pump it up! The sluggish reactivity of organozinc reagents in additions to aldehydes, ketones, and CO2 can be increased by MgCl2, which is usually generated in the preparation of the zinc reagent. The direct reaction with CO2, in particular, opens an expeditious route to phenylacetic acid derivatives, as demonstrated in a short synthesis of ibuprofen (see scheme).
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。
Iron-Catalyzed C–C Single-Bond Cleavage of Alcohols
作者:Wei Liu、Qiang Wu、Miao Wang、Yahao Huang、Peng Hu
DOI:10.1021/acs.orglett.1c03137
日期:2021.11.5
An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C–C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a
Synthesis of Hexahydrocyclopenta[c]furans by an Intramolecular Iron-Catalyzed Ring Expansion Reaction
作者:Gerhard Hilt、Patrick Bolze、Maja Heitbaum、Katrin Hasse、Klaus Harms、Werner Massa
DOI:10.1002/adsc.200700035
日期:2007.8.6
The intramolecular iron-catalyzed ring expansionreaction of epoxyalkenes was investigated with a preformed iron(salen) [Fe(Salen)] complex. The formal insertion of the alkene into the epoxide generated hexahydrocyclopenta[c]furan derivatives in moderate to good yields and diastereoselectivities depending on other functional groups present in the starting materials. In addition, oxygen-tethered epoxyalkenes
用预先形成的铁(salen)[Fe(Salen)]配合物研究了环氧烯烃的分子内铁催化的环膨胀反应。取决于起始原料中存在的其他官能团,烯烃以中等至良好的产率和非对映选择性正式插入环氧化物生成的六氢环戊[ c ]呋喃衍生物中。另外,将氧束缚的环氧烯烃用于木脂素异构体的合成。讨论了Fe(Salen)催化反应过程的范围和局限性。
Terminal Trifluoromethylation of Ketones via Selective C–C Cleavage of Cycloalkanols Enabled by Hypervalent Iodine Reagents
We report the first terminal trifluoromethylation at aryl and alkyl ketones’ γ, δ, ε, or more remote sites via the selective C–C bond cleavage of cycloalkanols. The noncovalent interactions between alcohols and hypervalent iodines(III) reagents were disclosed to activate both alcohols and the Togni I reagent in the dual photoredox/copper catalysis for the transformation. This reaction was scalable
我们报告了通过环烷醇的选择性 C-C 键断裂在芳基和烷基酮的 γ、δ、ε 或更远的位点发生的第一个末端三氟甲基化。公开了醇和高价碘 (III) 试剂之间的非共价相互作用,以在双光氧化还原/铜催化转化中激活醇和 Togni I 试剂。该反应可扩展到克级合成,适用于结构复杂的类固醇三氟甲基化,并可扩展到五氟乙基化。