Photooxidizing Chromium Catalysts for Promoting Radical Cation Cycloadditions
作者:Susan M. Stevenson、Matthew P. Shores、Eric M. Ferreira
DOI:10.1002/anie.201501220
日期:2015.5.26
The photooxidizing capabilities of selected CrIII complexes for promotingradicalcationcycloadditions are described. These complexes have sufficiently long‐lived excited states to oxidize electron‐rich alkenes, thereby initiating [4+2] processes. These metal species augment the spectrum of catalysts explored in photoredox systems, as they feature unique properties that can result in differential
A biosynthetically inspired route to substituted furans using the Appel reaction: total synthesis of the furan fatty acid F<sub>5</sub>
作者:Robert J. Lee、Martin R. Lindley、Gareth J. Pritchard、Marc C. Kimber
DOI:10.1039/c7cc03229c
日期:——
Appel reaction conditions have been harnessed to affect a mild biosynthetically inspired dehydration of endoperoxides to deliver multi-substituted electron rich furans. Unlike traditional dehydrative procedures, this method is metal and acid free, and can be achieved under redox neutral conditions. It is general for a range of aryl and alkyl substituted endoperoxides, and is functional group tolerant
Enantioselective Organo-SOMO Cycloadditions: A Catalytic Approach to Complex Pyrrolidines from Olefins and Aldehydes
作者:Nathan T. Jui、Jeffrey A. O. Garber、Fernanda Gadini Finelli、David W. C. MacMillan
DOI:10.1021/ja305076b
日期:2012.7.18
2) coupling of aldehydes and conjugatedolefins has been accomplished. A radical-polar crossover mechanism is proposed wherein olefin addition to a transient enamine radical cation and oxidation of the resulting radical furnish a cationic intermediate which is vulnerable to nucleophilic addition of a tethered amine group. A range of olefins, including styrenes and dienes, are shown to provide stereochemically
Catalytic Enantioselective Hetero-dimerization of Acrylates and 1,3-Dienes
作者:Stanley M. Jing、Vagulejan Balasanthiran、Vinayak Pagar、Judith C. Gallucci、T. V. RajanBabu
DOI:10.1021/jacs.7b10055
日期:2017.12.13
counterion, and solventeffects uncovered during the course of these investigations show a unique role of a possible cationic Co(I) intermediate in these reactions. The rational evolution of a mechanism-based strategy that led to the eventual successful outcome and the attendant support studies may have further implications for the expanding use of low-valent group 9 metal complexes in organic synthesis
and imines with a nucleophilic group is also compatible, by trapping in situ formed π-allylpalladium species after initial ene addition. This π-Lewis base catalytic mode, featuring simple η2coordination, vinylogous activation, and compatibility with both conjugated neutral polyenes and electron-deficient polyenes, is elucidated by control experiments and density functional theory (DFT) calculations.
在这里,我们报告说,钯 (0) 配合物可以以 η 2 的方式与 1,3-二烯配位,并通过将电子从 d 轨道捐赠给空的反键分子,从而显着提高其最高占据分子轨道 (HOMO) 的能量通过反键连接的双键 (π*) 轨道。因此,未配位的双键作为基于乙烯学原理的更具反应性的伙伴,可以直接攻击亚胺,提供对映选择性的正式加氢二烯化反应。通过原位捕获, 1,3-二烯和具有亲核基团的亚胺之间的化学选择性级联乙烯基加成/烯丙基烷基化双官能化过程也是相容的在初始加入烯后形成 π-烯丙基钯物种。这种 π-刘易斯碱催化模式具有简单的 η 2配位、乙烯基活化以及与共轭中性多烯和缺电子多烯的相容性,通过控制实验和密度泛函理论 (DFT) 计算得到阐明。