SO<sub>2</sub>F<sub>2</sub>-Mediated Epoxidation of Olefins with Hydrogen Peroxide
作者:Chengmei Ai、Fuyuan Zhu、Yanmei Wang、Zhaohua Yan、Sen Lin
DOI:10.1021/acs.joc.9b01784
日期:2019.9.20
An inexpensive, mild, and highly efficient epoxidation protocol has been developed involving bubbling SO2F2 gas into a solution of olefin, 30% aqueous hydrogenperoxide, and 4 N aqueous potassium carbonate in 1,4-dioxane at room temperature for 1 h with the formation of the corresponding epoxides in good to excellent yields. The novel SO2F2/H2O2/K2CO3 epoxidizing system is suitable to a variety of
Thioether-Directed NiH-Catalyzed Remote γ-C(sp<sup>3</sup>)–H Hydroamidation of Alkenes by 1,4,2-Dioxazol-5-ones
作者:Bingnan Du、Yuxin Ouyang、Qishu Chen、Wing-Yiu Yu
DOI:10.1021/jacs.1c05834
日期:2021.9.22
amidation of unactivated alkenes. Due to the preference for five-membered nickelacycle formation, the chain-walking isomerization initiated by the NiH insertion to an alkene can be terminated at the γ-methylene site remote from the alkene moiety. By employing 2,9-dibutyl-1,10-phenanthroline (L4) as the ligand and dioxazolones as the reagent, the amidation occurs at the γ-C(sp3)–H bonds to afford the amide
Ti-Catalyzed Diastereoselective Cyclopropanation of Carboxylic Derivatives with Terminal Olefins
作者:Jiabin Ni、Xiaowen Xia、Wei-Feng Zheng、Zhaobin Wang
DOI:10.1021/jacs.2c02360
日期:2022.5.4
cyclopropylamines from widely accessible carboxylic derivatives (acids, esters, amides) with terminal olefins. To the best of our knowledge, this method represents the first example of direct converting alkyl carboxylic acids into cyclopropanols. Distinct from conventional studies in Ti-mediated cyclopropanations with reactive alkyl Grignard reagents as nucleophiles or reductants, this protocol utilizes Mg
Stereodivergent, Kinetically Controlled Isomerization of Terminal Alkenes via Nickel Catalysis
作者:Camille Z. Rubel、Anne K. Ravn、Hang Chi Ho、Shenghua Yang、Zi‐Qi Li、Keary M. Engle、Julien C. Vantourout
DOI:10.1002/anie.202320081
日期:2024.5.21
mono-transposition generates E- or Z-olefins depending on the steric properties and denticity of the ligand employed. Mechanistic studies reveal that the aryl iodide additive acts as a redox buffer for nickel in the Z-selective reaction, generating the most-selective NiII–H that outcompetes a less Z-selective NiI–H species. For the E-selective reaction, the phosphonium salt plays a dual role as an acid
镍催化的动态烯烃单转位根据所用配体的空间性质和齿数产生E-或Z-烯烃。机理研究表明,芳基碘化物添加剂在Z选择性反应中充当镍的氧化还原缓冲剂,生成选择性最高的 Ni II -H,从而击败Z选择性较低的 Ni I -H 物种。对于E-选择性反应,鏻盐起到酸和配体的双重作用,原位形成膦结合的阳离子Ni−H催化剂。