Iron(II) and Copper(I) Control the Total Regioselectivity in the Hydrobromination of Alkenes
作者:Daniel A. Cruz、Victoria Sinka、Pedro de Armas、Hugo Sebastian Steingruber、Israel Fernández、Víctor S. Martín、Pedro O. Miranda、Juan I. Padrón
DOI:10.1021/acs.orglett.1c02186
日期:2021.8.6
A new method that allows the complete control of the regioselectivity of the hydrobrominationreaction of alkenes is described. Herein, we report a radical procedure with TMSBr and oxygen as common reagents, where the formation of the anti-Markovnikov product occurs in the presence of parts per million amounts of the Cu(I) species and the formation of the Markovnikov product occurs in the presence
Bi(III) halides as efficient catalysts for the O-acylative cleavage of tetrahydrofurans: an expeditious entry to tetralins
作者:Simon J. Coles、James F. Costello、William N. Draffin、Michael B. Hursthouse、Simon P. Paver
DOI:10.1016/j.tet.2005.02.080
日期:2005.5
O-acylative cleavage of tetrahydrofurans using organic acid halides with catalytic Bi(III) halides is reported. X-ray crystallography is used to rationalise the failure of the reaction in the case of certain crowded acid chlorides, and a useful aspect of chemoselectivity is revealed. The synthetic potential of this reaction is illustrated with a highly efficient O-acylative cleavage/intramolecular
Palladium(II) acetate catalyzed acylative cleavage of cyclic and acyclic ethers under neat conditions
作者:Jean Fotie、Brandy R. Adolph、Shreya V. Bhatt、Casey C. Grimm
DOI:10.1016/j.tetlet.2017.10.080
日期:2017.12
During the development of a palladiumcatalyzed C–H activation cross-coupling reaction involving acyl halides, it was noted that palladium(II) acetate catalyzes the acylative cleavage of tetrahydrofuran (used as a solvent) at room temperature to afford the corresponding 4-chlorobutyl ester derivative. After optimization, the reaction was shown to work well with epoxides, oxetane and tetrahydrofuran
Direct Alkylation of Glycine Derivatives via Photoinduced Palladium Catalysis, Utilizing Intermolecular Hydrogen Atom Transfer Mediated by Alkyl Radicals
作者:Sen Yang、Hao Hu、Jun-hua Li、Ming Chen
DOI:10.1021/acscatal.3c04075
日期:2023.12.15
while showcasing remarkable tolerance toward diverse functional groups. To shed light on the underlying mechanism, extensive investigations involving control experiments, deuterium labeling, radical clocking, and kinetic studies have been conducted. The collected data consistently support a reaction pathway involving the formation of Pd(I)/alkyl hybrid species followed by intermolecular HAT and elimination
烷基/Pd杂化物种是一种独特的以sp3-C为中心的自由基,可在甘氨酸衍生物直接烷基化的开发中促进分子间氢原子转移(HAT)。这种转化反应在简单温和的条件下顺利进行,在涵盖甘氨酸衍生物和烷基溴的底物范围方面表现出令人印象深刻的多功能性,同时表现出对不同官能团的显着耐受性。为了阐明潜在的机制,已经进行了涉及控制实验、氘标记、自由基时钟和动力学研究的广泛研究。收集到的数据一致支持反应途径,包括形成 Pd(I)/烷基杂化物,然后进行分子间 HAT 和消除步骤,从而导致亚胺中间体的原位形成,最终通过自由基加成在最后阶段达到顶峰。
Regiodivergent Conversion of Alkenes to Branched or Linear Alkylpyridines
作者:Minseok Kim、Sanghoon Shin、Yejin Koo、Sungwoo Jung、Sungwoo Hong
DOI:10.1021/acs.orglett.1c04156
日期:2022.1.21
Herein we report a practical protocol for the visible-light-induced regiodivergent radical hydropyridylation of unactivated alkenes using pyridiniumsalts. This approach provides a unified synthetic platform to control the regioselectivity of the synthesis of linear or branched C4-alkylated pyridines. A remarkable selectivity switch from the anti-Markovnikov to the Markovnikov product can be achieved