已经制备了双功能铜基光催化剂,其使用掺入磺酰胺部分的吡唑-吡啶配体,该磺酰胺部分用作光化学PCET工艺的分子内氢键供体。在典型的还原性PCET工艺中,光催化剂和H键供体必须分别具有适当的氧化还原电势和p K a,以促进PCET。当在双功能催化剂(例如Cu(pypzs)(BINAP)BF 4)中协同工作时,p K a氢键供体的一半酸度可以降低几个数量级,并且仍然可以有效地促进PCET过程。可以使用贱金属衍生的光催化剂进行频哪醇还原型偶联,以从易得的醛和酮中获得有价值的二醇(24个实例,收率46-99%)。
It was firstly found that the Rieke Ni generated in situ was able to promote the pinacol coupling of various carbonyls efficiently. Based on this information, another catalytically effective, cheaper and more convenient NiCl2(Cat.)/Mg/TMSCl system was designed and developed further successfully. The interesting single-electron transfer (SET) mechanisms for the coupling reactions were proposed. Additionally
Isothiourea-Catalysed Sequential Kinetic Resolution of Acyclic (±)-1,2-Diols
作者:Siegfried Harrer、Mark D. Greenhalgh、Rifahath M. Neyyappadath、Andrew D. Smith
DOI:10.1055/s-0037-1610721
日期:2019.8
The isothiourea-catalysed acylative kineticresolution of a range of acyclic (±)-1,2-diols using 1 mol% of catalyst under operationally simple conditions is reported. Significantly, the bifunctional nature of (±)-1,2-diols was exploited in a sequential double kineticresolution, in which both kineticresolutions operate synergistically to provide access to highly enantioenriched products. The principles
Magnesium-Mediated Carbon−Carbon Bond Formation in Aqueous Media: Barbier−Grignard Allylation and Pinacol Coupling of Aldehydes
作者:Wen-Chun Zhang、Chao-Jun Li
DOI:10.1021/jo982497p
日期:1999.4.1
alkylation of aldehydes with alkyl halides was studied in aqueousmedia. The reaction of aromatic aldehydes with allyl halides is highly effective with either THF or water as the reaction solvent but poor in a mixture of THF/water. It was found that the magnesium-mediated allylation of aldehydes with allyl bromide and iodide proceeds effectively in aqueous 0.1 N HCl or 0.1 N NH(4)Cl. Aromatic aldehydes reacted
在含水介质中研究了镁介导的Barbier-Grignard型醛与烷基卤化物的烷基化反应。用THF或水作为反应溶剂,芳族醛与烯丙基卤的反应非常有效,但是在THF /水的混合物中效果较差。已经发现,镁与烯丙基溴和碘的醛介导的烯丙基化在0.1 N HCl或0.1 N NH(4)Cl水溶液中有效进行。芳族醛在脂肪族醛的存在下发生化学选择性反应。当脂族和芳族醛官能团同时存在于同一分子中时,也观察到排他选择性。在不存在烯丙基卤的情况下,醛和酮与镁在0.1 N NH(4)Cl水溶液中反应形成高产率的相应频哪醇偶联产物。频哪醇反应的有效性受到羰基周围空间环境的强烈影响。脂肪醛和简单的烷基卤化物在用于烷基化或频哪醇偶联反应的反应条件下呈惰性。
Rapid Oxidation of 1,2-Diols,<i>α</i>-Hydroxyketones and Some Alcohols using<i>N</i>-Bromosuccinimide in Ionic Liquid
作者:Jitender M. Khurana、Ankita Chaudhary、Sanjay Kumar
DOI:10.1080/00304948.2013.786585
日期:2013.5.4
Oxidation of 1,2-diols, α-hydroxyketones and alcohols to carbonyl compounds is of great importance in organic synthesis1 and can be achieved with an array of reagents such as chromium(VI)-based reagents,2 hypervalent iodine reagents,3 and DABCO/Br2, DMSO/N2H4.H2O/I2/H2O/CH3CN. The oxidation of α-hydroxyketones to 1,2-diketones has also been reported by a variety of reagents including pyridinium chlorochromate
Thiadiazole dioxide-fused picene: acceptor ability, anion radical formation, and n-type charge transport characteristics
作者:Yongfa Xie、Yoshiaki Shuku、Michio M. Matsushita、Kunio Awaga
DOI:10.1039/c3cc49500k
日期:——
Picene, which is an organic p-channel semiconductor and a component of superconductors, was derivatized with a thiadiazole-dioxide moiety to afford a novel acceptor molecule (PTDAO2). PTDAO2 can form stable anion radical species in solution and as a crystal, and its neutral crystalline thin film exhibits n-type transistor characteristics.