A photoredox and Brønsted acid synergistically catalyzed cross‐dehydrogenative C−Ocouplingreaction is developed in which isochroman peroxyacetals are formed through sp3 C−H bond peroxidation. The reported method is characterized by its extremely mild reaction conditions, excellent yields, and broad substrate scope. An oxocarbenium ion p‐chlorobenzenesulfonate was speculated to be the reactive intermediate
Hypervalent (<i>tert</i>-Butylperoxy)iodanes Generate Iodine-Centered Radicals at Room Temperature in Solution: Oxidation and Deprotection of Benzyl and Allyl Ethers, and Evidence for Generation of α-Oxy Carbon Radicals
reductive deprotection. Oxidation with 1a occurs readily with C−H bonds activated by both enthalpic effects (benzylic, allylic, and propargylic C−H bonds) and/or polar effects (α-oxy C−H bonds), generating α-oxy carbon-centered radicals, which can be detected by nitroxyl radical trapping. Measurement of the relative rates of oxidation for a series of ring-substituted benzyl n-butyl ethers 2d and 2p−s
Allylic and benzylic alcohols were oxidized in good yields to the respective ketones by tert-butylhydroperoxide (TBHP) in the presence of copper salts under phase-transfer catalysis conditions. This dehydrogenation was found to proceed via a heterolytic mechanism. CuCl2, CuCl, and even copper powder were equally facile as catalysts, as they were all transformed in situ to Cu(OH)Cl which was extracted
在相转移催化条件下,在铜盐存在下,叔丁基氢过氧化物(TBHP)将烯丙醇和苄醇以良好的产率氧化为相应的酮。发现该脱氢是通过杂化机理进行的。CuCl 2,CuCl甚至铜粉同样容易用作催化剂,因为它们都可以原位转化得到Cu(OH)Cl,其被相转移催化剂(PTC)萃取到有机相中。氘标记实验证明了在速率测定步骤中苄基CH键的断裂。在醇底物的存在下未观察到非生产性TBHP分解。相反,发现在同一介质中的π-活化的亚甲基的氧合是一个自由基过程,主要产物是合适的叔丁基过氧化物。讨论了催化剂的失活,溶剂作用和萃取作用。通过应用的Minisci的关于TBHP分子朝着相对反应性的假定叔-质子和非质子环境中的-丁氧基自由基,可以解释均解和杂化途径的共存。提出了一种完整的反应机理,其中自由基氧化遵循高知的机理,并且杂合脱氢基于高价Cu IV O物种或[Cu(OH)Cl] 2物种。
Green Organic Solvent-Free Oxidation of Alkylarenes with tert-Butyl Hydroperoxide Catalyzed by Water-Soluble Copper Complex
作者:Abdelaziz Nait Ajjou、Ateeq Rahman
DOI:10.1515/chem-2020-0018
日期:2020.3.24
Abstract Different benzylic compounds were efficiently oxidized to the corresponding ketones with aqueous 70% tert-butylhydroperoxide (TBHP) and the catalytic system composed of CuCl2.2H2O and 2,2’-biquinoline-4,4’-dicarboxylic acid dipotassium salt (BQC). The catalytic system CuCl2/BQC/TBHP allows obtaining high yields at room temperature under organic solvent-free conditions. The interest of this
The selective functionalization of saturated hydrocarbons. Part 28. The activation of benzylic methylene groups under GoAggIV and GoAggV conditions
作者:Derek H.R. Barton、Wang Tie-Lin
DOI:10.1016/s0040-4020(01)80814-0
日期:1994.1
anthracene was oxidized to give anthraquinone. Under GoAggIV and GoAggV conditions, xanthene, fluorene and diphenylmethane were oxidized to give the corresponding xanthone, fluorenone and benzophenone following two possible pathways: a) alkane to alkyl t-butylperoxide to ketone, and b) alkane to ketone, in which alkyl hydroperoxide, derived from oxygen, may be the reaction intermediate. Xanthyl azide was