Metal-Free Dihydroxylation of Alkenes using Cyclobutane Malonoyl Peroxide
摘要:
Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of I equiv of water at 40 degrees C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 -> 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and gamma-lactones.
Metal-Free Dihydroxylation of Alkenes using Cyclobutane Malonoyl Peroxide
摘要:
Cyclobutane malonoyl peroxide (7), prepared in a single step from the commercially available diacid 6, is an effective reagent for the dihydroxylation of alkenes. Reaction of a chloroform solution of 7 with an alkene in the presence of I equiv of water at 40 degrees C followed by alkaline hydrolysis leads to the corresponding diol (30-84%). With 1,2-disubstituted alkenes, the reaction proceeds with syn-selectivity (3:1 -> 50:1). A mechanism consistent with experimental findings is proposed, which is supported by deuterium and oxygen labeling studies and explains the stereoselectivity observed. Alternative reaction pathways that are dependent on the structure of the starting alkene are also described leading to the synthesis of allylic alcohols and gamma-lactones.
C−O coupling of Malonyl Peroxides with Enol Ethers
<i>via</i>
[5+2] Cycloaddition: Non‐Rubottom Oxidation
作者:Vera A. Vil'、Evgenii S. Gorlov、Oleg V. Bityukov、Yana A. Barsegyan、Yulia E. Romanova、Valentina M. Merkulova、Alexander O. Terent'ev
DOI:10.1002/adsc.201900271
日期:2019.7.2
Malonyl peroxides act both as oxidants and reagents for C−O coupling in reactions with methyl and silyl enol ethers. In the proposed conditions, the oxidative C−O coupling of malonyl peroxides with enol ethers selectively proceeds, bypassing the traditional Rubottom hydroxylation of enol ethers by peroxides. It was observed that the oxidative [5+2] cycloaddition of malonyl peroxides and enol ethers
Oxidative C–O coupling as a new idea in the ‘click-like chemistry’: malonyl peroxides for the conjugation of two molecules
作者:Vera A. Vil’、Evgenii S. Gorlov、Oleg V. Bityukov、Igor B. Krylov、Gennady I. Nikishin、Kasimir K. Pivnitsky、Alexander O. Terent’ev
DOI:10.1016/j.mencom.2019.03.003
日期:2019.3
Malonylperoxides were used for the one-pot construction of hybrid structures by conjugation of heterocycle (3H-pyrazol-3-one, isoxazol-5(2H)-one, pyrazolidine-3,5-dione, or barbituric acid) and amine or alcohol. The first stage represents oxidative C–O coupling with liberation of the carboxyl group which is functionalized at the second stage thus affording ‘clicklike’ products with malonic linker
Activation of O-Electrophiles <i>via</i> Structural and Solvent Effects: S<sub>N</sub>2@O Reaction of Cyclic Diacyl Peroxides with Enol Acetates
作者:Vera A. Vil’、Evgenii S. Gorlov、Diana V. Shuingalieva、Artem Yu. Kunitsyn、Nikolai V. Krivoshchapov、Michael G. Medvedev、Igor V. Alabugin、Alexander O. Terent’ev
DOI:10.1021/acs.joc.2c01634
日期:2022.11.4
and computationally. Computational analysis reveals that the key step proceeds as a direct substitution nucleophilic bimolecular (SN2) reaction at oxygen (SN2@O). CF3CH2OH has a dual role in assisting in both steps of the reaction cascade: it lowers the energy of the SN2@O activation step by hydrogen bonding to a remote carbonyl and promotes the deacylation of the cationic intermediate.
O-亲电子试剂(如有机过氧化物)与碳亲核试剂的反应是 C-O 键形成常用方法的一种替代方法。环状二酰基过氧化物的氧原子被烯醇乙酸酯亲核取代并进行随后的脱酰化反应,生成带有附加羧酸的 α-酰氧基酮,产率为 28-87%。通过实验和计算研究了氟化醇对环状二酰基过氧化物对烯醇乙酸酯的氧化官能化的影响。计算分析表明,关键步骤是在氧气 (S N 2@O)上进行直接取代亲核双分子 (S N 2) 反应。CF 3通道2OH 在协助反应级联的两个步骤中具有双重作用:它通过与远程羰基形成氢键来降低 S N 2@O 活化步骤的能量,并促进阳离子中间体的脱酰作用。
Creating, Preserving, and Directing Carboxylate Radicals in Ni-Catalyzed C(sp<sup>3</sup>)–H Acyloxylation of Ethers, Ketones, and Alkanes with Diacyl Peroxides
作者:Vera A. Vil’、Yana A. Barsegyan、Leah Kuhn、Alexander O. Terent’ev、Igor V. Alabugin
DOI:10.1021/acs.organomet.2c00663
日期:——
The reaction of Ni(II) acetate with diacyl peroxides produces high-valence Ni-species capable of catalytic oxidative acyloxylation of C(sp3)–H bonds in ethers, ketones, and alkanes. The desired esters were obtained in 20–82% yields. Computational analysis suggests that activation of the peroxide moiety produces a dynamically interconverting mixture of catalytic Ni-species in the formal Ni(III) state
乙酸镍 (II) 与二酰基过氧化物反应生成高价镍物质,能够催化醚、酮和烷烃中C(sp 3 )–H 键的氧化酰氧基化。获得了所需的酯,产率为 20-82%。计算分析表明,过氧化物部分的活化会产生形式 Ni(III) 状态的催化 Ni 物质的动态互变混合物。值得注意的是,在这些物种中,RCO 2的协调Ni 上的基团保留了羧酸酯部分的自由基特征(即,羧酸酯自由基充当“L-配体”),因此后者可以诱导快速的 C-H 抽象。螺环丙基部分通过杂化因子和立体电子效应的组合防止过早自由基脱羧。通过实验和计算确定了多种可行的 C-H 激活模式。
Alkene Syn Dihydroxylation with Malonoyl Peroxides
作者:James C. Griffith、Kevin M. Jones、Sylvain Picon、Michael J. Rawling、Benson M. Kariuki、Matthew Campbell、Nicholas C. O. Tomkinson
DOI:10.1021/ja1066674
日期:2010.10.20
Cyclopropyl malonoyl peroxide (1), which can be prepared in a single step from the commercially available diacid, is an effective reagent for the dihydroxylation of alkenes. Reaction of 1 with an alkene in the presence of 1 equiv of water at 40 degrees C followed by alkaline hydrolysis leads to the corresponding diol (40-93%). With 1,2-disubstituted alkenes, the reaction proceeds with syn selectivity (3:1 to > 50:1). A mechanism consistent with the experimental findings that is supported by oxygen-labeling studies is proposed.