Towards practical earth abundant reduction catalysis: design of improved catalysts for manganese catalysed hydrogenation
作者:Magnus B. Widegren、Matthew L. Clarke
DOI:10.1039/c9cy01601e
日期:——
Manganese catalysts derived from tridentate P,N,N ligands can be activated easily using weak bases for both ketone and ester hydrogenations. Kinetic studies indicate the ketone hydrogenations are 0th order in acetophenone, positive order in hydrogen and 1st order in the catalyst. This implies that the rate determining step of the reaction was the activation of hydrogen. New ligand systems with varying
A water-soluble highly efficient iridium catalyst is developed for the chemoselective reduction of aldehydes to alcohols in water. The reductionuses formic acid as the traceless reducing agent and water as a solvent. It can be carried out in air without the need for inert atmosphere protection. The products can be purified by simple extraction without any column chromatography. The catalyst loading
开发了一种水溶性高效铱催化剂,用于将水中的醛化学选择性还原为醇。还原使用甲酸作为无痕还原剂,并使用水作为溶剂。它可以在空气中进行,而无需惰性气体保护。可以通过简单的萃取来纯化产物,而无需任何柱色谱法。催化剂负载量可以低至0.005mol%,并且转换频率(TOF)高至73800mol mol -1 h -1。各种各样的官能团,例如富电子或不足的(杂)芳烃和烯烃,烷氧基,卤素,酚,酮,酯,羧酸,氰基和硝基,都具有良好的耐受性,这表明其具有出色的化学选择性。
Regio- and Enantioselective Allylation of Phenols<i>via</i>Decarboxylative Allylic Etherification of Allyl Aryl Carbonates Catalyzed by (Cyclopentadienyl)ruthenium(II) Complexes and Pyridine-Hydrazone Ligands
作者:Léo Egger、Cecilia Tortoreto、Thierry Achard、David Monge、Abel Ros、Rosario Fernández、José M. Lassaletta、Jérôme Lacour
DOI:10.1002/adsc.201500534
日期:2015.10.12
(Cyclopentadienyl)tris(acetonitrile)ruthenium hexafluorophosphate [CpRu(CH3CN)3][PF6] in combination with pyridine-hydrazone ligands efficiently catalyzes the asymmetric decarboxylative allylic rearrangement of allylarylcarbonates. Formation of CO bonds with high regio- and enantioselectivity ratios (up to 95:5 and 98% ee) is obtained. Good stereocontrol of the pseudotetrahedral geometry of the CpRu
Iron Catalyzed Highly Enantioselective Epoxidation of Cyclic Aliphatic Enones with Aqueous H<sub>2</sub>O<sub>2</sub>
作者:Olaf Cussó、Marco Cianfanelli、Xavi Ribas、Robertus J. M. Klein Gebbink、Miquel Costas
DOI:10.1021/jacs.5b12681
日期:2016.3.2
An iron complex with a C1-symmetric tetradentate N-based ligand catalyzes the asymmetric epoxidation of cyclic enones and cyclohexene ketones with aqueous hydrogen peroxide, providing the corresponding epoxides in good to excellent yields and enantioselectivities (up to 99% yield, and 95% ee), under mild conditions and in short reaction times. Evidence is provided that reactions involve an electrophilic
具有 C1 对称四齿 N 基配体的铁配合物催化环烯酮和环己烯酮与过氧化氢水溶液的不对称环氧化反应,提供相应的环氧化物,产率和对映选择性都很好(高达 99% 和 95% ee ),条件温和,反应时间短。有证据表明反应涉及亲电氧化剂,并且该元素用于对包含两个烯烃位点的烯酮进行位点选择性环氧化。
Tuning of the Properties of Transition-Metal Bispidine Complexes by Variation of the Basicity of the Aromatic Donor Groups
作者:Peter Comba、Michael Morgen、Hubert Wadepohl
DOI:10.1021/ic4004214
日期:2013.6.3
find broad application in the field of coordination chemistry, and the redox potentials of their transition-metal complexes are of importance in oxidation reactions by high-valent iron complexes, aziridination catalyzed by copper complexes, and imaging by 64Cu positron emission tomography tracers. Here, we show that the redox potentials and stability constants of the copper(II) complexes of 15 tetradentate
联吡啶(3,7-二氮杂双环[3.3.1]壬烷)是非常刚性和高度组织化的配体,在配位化学领域得到广泛应用,它们的过渡金属配合物的氧化还原电势在高氧氧化反应中很重要。价铁络合物,铜络合物催化的叠氮化和64 Cu铜正电子发射断层显像剂成像。在这里,我们显示了15个四齿联吡啶的铜(II)配合物的氧化还原电势和稳定性常数可以通过取代吡啶环来改变(氧化还原电势在约450 mV以上的变化和复合物稳定性在约10 mV以上的变化)日志单位)。还表明,这些变化可以通过p K a预测。吡啶基团的值以及取代基的哈米特参数,以及基于密度泛函理论的能量分解分析,还可以使人们准确地预测氧化还原电势和随之而来的配合物稳定性。结果表明,主要贡献来自于静电相互作用能,因此吡啶供体基团的部分电荷也与氧化还原电势相关。