Herein, we report an efficient method for the tertiary alkylation of a ketone by using an α‐bromocarbonyl compound as the tertiary alkyl source in a combined Cu‐organocatalyst system. This dual catalyst system enables the addition of a tertiary alkyl radical to an enamine. Mechanistic studies revealed that the catalytically generated enamine is a key intermediate in the catalytic cycle. The developed
Directed Copper-Catalyzed Intermolecular Heck-Type Reaction of Unactivated Olefins and Alkyl Halides
作者:Chunlin Tang、Ran Zhang、Bo Zhu、Junkai Fu、Yi Deng、Li Tian、Wei Guan、Xihe Bi
DOI:10.1021/jacs.8b10874
日期:2018.12.12
A new type of intermolecular alkylative olefination of unactivated olefins and alkyl halides has been realized for the first time. This copper-promoted Heck-type reaction employs a directing-group strategy to efficiently produce the coupled alkyl olefin products with excellent regio- and stereoselectivity. A broad substrate scope including 1°, 2°, and 3° alkyl bromides and various nonactivated alkenes
Synthesis of Hindered α-Amino Carbonyls: Copper-Catalyzed Radical Addition with Nitroso Compounds
作者:David J. Fisher、G. Leslie Burnett、Rocío Velasco、Javier Read de Alaniz
DOI:10.1021/jacs.5b07860
日期:2015.9.16
The synthesis of sterically hindered anilines has been a significant challenge in organic chemistry. Here we report a Cu-catalyzed radical addition with in situ-generated nitrosocompounds to prepare sterically hindered amines directly from readily available materials. The transformation is conducted at room temperature, uses abundant copper salts, and is tolerant of a range of functional groups.
空间位阻苯胺的合成一直是有机化学中的一个重大挑战。在这里,我们报告了 Cu 催化的自由基加成与原位生成的亚硝基化合物,以直接从容易获得的材料制备位阻胺。转化在室温下进行,使用丰富的铜盐,并且可以耐受一系列官能团。
Controlling Reactivity by Geometry in Retro-Diels–Alder Reactions under Tension
作者:Richard Stevenson、Guillaume De Bo
DOI:10.1021/jacs.7b08895
日期:2017.11.22
chemical reactions. In polymer mechanochemistry, the force is transduced in a directional fashion, and the efficiency of activation depends on how well the force is transduced from the polymer to the scissile bond in the mechanophore (i.e., mechanochemical coupling). We have investigated the effects of regio- and stereochemistry on the rate of force-accelerated retro-Diels–Alder reactions of furan/maleimide
机械力具有扭曲,弯曲和拉伸化学键的能力,在激活化学反应的方式上是独特的。在聚合物力学化学中,力是以定向方式传递的,活化的效率取决于力从聚合物传递到力学基团中的易断裂键的传递程度(即,机械化学偶联)。我们研究了区域化学和立体化学对呋喃/马来酰亚胺加合物强制加速逆Diels-Alder反应速率的影响。呈现内或外构型以及近端或远端几何形状的四个加合物在溶液中被超声产生的伸长力激活。组合结构(11 H NMR)和计算分析(CoGEF)使我们能够研究这些加合物的机械化学活化。我们发现,与其反应性由立体化学决定的热对应物不同,机械反应性主要取决于区域化学。值得注意的是,由于不良的机械化学偶联作用,热活性远侧-外加合物在张力下变得惰性。
A Catenane as a Mechanical Protecting Group
作者:Min Zhang、Guillaume De Bo
DOI:10.1021/jacs.0c01757
日期:2020.3.18
mechanophores can be tuned by altering its structure or the composition of the actu-ating polymer. Here we show that a [2]catenane can act as a mechanical protectinggroup by diverting tensional forces away from a mechanically active functional group embedded in one of its rings. This property emerges from the mobility of the two rings of the catenane, which are able to rotate along each other until the