Cp* Iridium Precatalysts for Selective C–H Oxidation with Sodium Periodate As the Terminal Oxidant
作者:Meng Zhou、Ulrich Hintermair、Brian G. Hashiguchi、Alexander R. Parent、Sara M. Hashmi、Menachem Elimelech、Roy A. Periana、Gary W. Brudvig、Robert H. Crabtree
DOI:10.1021/om301252w
日期:2013.2.25
Sodium periodate (NaIO4) is shown to be a milder and more efficient terminal oxidant for C–H oxidation with Cp*Ir (Cp* = C5Me5) precatalysts than ceric(IV) ammonium nitrate. Synthetically useful yields, regioselectivities, and functional group tolerance were found for methylene oxidation of substrates bearing a phenyl, ketone, ester, or sulfonate group. Oxidation of the natural products (−)-ambroxide
与硝酸铈(IV)铵相比,高碘酸钠(NaIO 4)是用Cp * Ir(Cp * = C 5 Me 5)进行C–H氧化的缓和和有效的终端氧化剂。对于带有苯基,酮,酯或磺酸酯基团的底物的亚甲基氧化,发现了在合成上有用的产率,区域选择性和官能团耐受性。天然产物(-)-氨氧化物和香紫苏内酯的氧化选择性进行,顺式-十氢萘羟基化中构型得以保留。在60°C时,即使是一级C–H键也可以被激活:而甲烷被过氧化为CO 2以总NaIO 4计,乙烷以39%的收率没有产生部分氧化的产物,以25%的收率将乙烷转化为乙酸。在18- OH 2和NaIO 4的顺式-萘烷羟基化中证明了18 O标记。在23°C的环己烷氧化中发现3.0±0.1的动力学同位素效应,这表明C–H键的裂解是限速步骤。C–H与水氧化的竞争实验表明,4-乙基苯磺酸钠的C–H氧化受到4个数量级的青睐。操作中 时间分辨的动态光散射和动力学分析排除了金属氧化物纳
Co(<scp>ii</scp>), a catalyst for selective conversion of phenyl rings to carboxylic acid groups
作者:Shashi Bhushan Sinha、Jesús Campos、Gary W. Brudvig、Robert H. Crabtree
DOI:10.1039/c4ra10510a
日期:——
We describe the use of Co(ii) in the presence of Oxone to effectively catalyze the conversion of –C6H5 to –COOH groups with a broad substrate scope, selectivity and under mild conditions.
A novel palladium-catalyzed approach for constructing 2,5-diarylated oxazole-4-carboxylates using sodium arylsulfinates as the aryl source has been demonstrated.
一种新颖的钯催化方法已被证明可用于利用亚砜酸钠作为芳基来源构建2,5-二芳基氧唑-4-羧酸酯。
Crystal growth, structures and magnetic properties of copper hydroxide compounds with distorted diamond chain magnetic networks
while 7 had a diamagnetic ground state. The different magneticproperties are due to the small structural differences in the diamond chain units, because the sign and intensity of magnetic coupling between the neighbouring copper ions are sensitive to the bridging structures. Copper hydroxide compounds with different organic ions and diverse structures prepared by this hydrolysis method will facilitate
soluble polymer-boundhydrogenationcatalyst that is homogeneous and active in basic aqueous media but insoluble and inactive in weakly acidic media is described. This catalyst is also active in organic solvents. In water, the catalyst can be recovered by acidifying the solution to a pH <5. In acetonitrile, the catalyst can be recovered by solvent (ether) precipitation. Activities of the catalyst are comparable