A Novel Synthesis of the Yohimbane Skeleton-Course of the Synthesis of 15,16,17,18,19,20-Hexadehydroyohimbane by Use of Palladium Catalyzed Insertion of Carbon Monoxide

In the course of our continuing synthetic experiments on benzoquinolizidine² and indoloquinolizidine alkaloids³, we have recently utilized palladium catalyzed amidation⁴ for the synthesis of the berbine alkaloids⁵. In this present paper we wish to report, what we believe is the first successful utilization of the palladium catalyzed amidation for the synthesis of the hexadehydroyohimbane skeleton.     

Biphasic Synthesis of Hydrogen Peroxide from Carbon Monoxide,Water, and Oxygen Catalyzed by Palladium Complexes with Bidentate Nitrogen Ligands

Effective and stable Pd catalysts for the biphasic synthesis of hydrogen peroxide from carbon monoxide, oxygen, and water [Eq. (a)] can be obtained by the right choice of bidentate nitrogen ligand. The best turnover numbers (578) for this reaction have been achieved with palladium complexes with 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ligands.     

The Reactions of Carbon Monoxide and Phenols Promoted by Palladium Complexes

The reaction of phenols with carbon monoxide at atmospheric pressure and room temperature in the presence of palladium cholrode and tertiary amine produces diaryl carbonates and aryl salicylates. Only diaryl cabonates are produced when palladium carbonyl cholride is substituted for palladium chloride. Reaction pathways are proposed.     

超临界二氧化碳介质中钯催化的一些交叉偶联反应的研究

构建新的C—C键, 在有机合成中占有非常重要的地位; 超临界二氧化碳, 作为环境友好的有机反应介质, 已引起人们的广泛关注. 综述了近年来超临界二氧化碳介质中钯催化的C—C键形成反应的研究进展, 包括Heck, Suzuki, Stille和Sonogashira反应等.     

Palladium Complexes as Catalysts for the Synthesis of Functional Polymers Based on Carbon Monoxide

A review of the history and present state of the use of palladium complexes in the synthesis of alternating CO copolymers with different monomers (mainly ethylene, propylene, and styrene) is presented. The effect of mono- and bidentate phosphine ligands, the nature of reaction medium and acid on the rate of the CO copolymerization with ethylene, and the effect of different bidentate PP, PN, and NN ligands on the structure and properties of chiral CO–propylene and CO-styrene copolymers are considered.     

Synthetic and Mechanistic Aspects of Inorganic Insertion Reactions. Insertion of Carbon Monoxide

The synthetic potential and the mechanistic aspects of inorganic insertion reactions of carbon monoxide, especially into metal-carbon σ-bonds, are considered. Reactions of this type are encountered among most 3d, 4d, and 5d elements. In one case it has been demonstrated that the CO insertion proceeds by alkyl migration; this is likely to be a general feature of all such reactions. If an alkyl migration takes place, then insertion of CO into the M? C bond is governed kinetically by the cleavage of that bond. CO abstraction from RCO? M bonds most commonly proceeds by rate-determining vacation of a coordination position. Both CO insertion and abstraction are usually highly stereospecific.     

无膦钯催化Heck反应合成新型芳维A酸类化合物

考察了以二环己基胺作配体的无膦钯催化Heck反应条件, 建立起一种新型的无膦钯催化Heck反应体系. 应用该体系可高收率(72%～84%)、高立体选择性(83%～95%)合成二取代和三取代二苯烯类化合物. 以2,4,5-三甲氧基苯乙烯、α-细辛脑为原料, 合成了4个尚未见文献报道的新型二苯烯类芳维A酸甲酯(3a, 3b, 4a, 4b), 并且在温和的水解体系[LiOH, V(THF)∶V(H₂O)＝5∶1]下顺利得到了它们的水解产物芳维A酸(5a, 5b, 6a, 6b), 产物通过¹H NMR, ¹³C NMR, IR和MS进行了结构确认.     

钯-稀土催化一氧化碳和苯乙烯交替共聚反应

 利用稀土钇盐或钕盐和乙酸钯组成的催化体系催化一氧化碳和苯乙烯共聚,合成了聚(1-氧代-2-苯基丙撑). 用元素分析、红外光谱、示差扫描量热、热重分析及X射线光电子能谱(XPS)等方法对共聚产物进行了表征. 测试结果表明,共聚物为一氧化碳和苯乙烯的线性交替共聚产物,其玻璃化温度为235 ℃,熔点为250 ℃,分解温度为325 ℃,且用XPS未检测到聚合物中含有残留的金属. 同时考察了催化剂组分2,2′-联吡啶、对甲苯磺酸和对苯醌及溶剂甲醇等的用量对共聚反应的影响,并对聚合反应条件进行了优化. 在优化的反应条件下稀土与钯组成的复合催化剂对一氧化碳和苯乙烯交替共聚的催化活性可达1200 g/(g·h).     

无膦配体氧化钯催化合成树形低聚苯

树形低聚苯;交叉偶联;无膦配体氧化钯催化合成树形低聚苯     

Adsorption of Carbon Monoxide on Palladium Electrode from Alkaline Solutions

Abstract

The adsorption of carbon monoxide from basic solution (0.1 M LiOH) on a palladium electrode was investigated. It was found that adsorption of CO takes place below the potential -0.25 V (vs. SCE). Surface concentration of the adsorption products, their composition and structure depend on the adsorption potential. The CO adsorption products block hydrogen absorption in palladium but in contrary to acidic solutions don't block the hydrogen desorption process.     

Copolymerization of Carbon Monoxide with Cyclic Compounds Catalyzed by Transition Metal Complexes

This article reviews recent discovery and progress of copolymerization of CO with cyclic monomers such as methylenecyclopropanes and propylene oxide promoted by transition metal complexes. 2-Aryl-1-methylenecyclopropanes react with CO in the presence of the Pd catalyst under mild conditions (1 atm, room temperature) to afford the polyketones. The reaction involves alternating insertion of the two monomers and opening of the three-membered ring of the cyclic monomers. Mechanistic study of the polymer growth revealed that 2-aryl-1-methylenecyclopropane undergoes 1,2-insertion into the Pd–acyl bond and subsequent -alkyl elimination of the cyclopropylmethylpalladium group. A bicyclic methylenecyclopropane, 7-methylenebicyclo[4.1.0]heptane, also reacts with CO in the presence of the Pd complexes with diimine ligands to afford the polyketone with six-membered rings in the repeating unit. The NMR spectra of the polyketone indicate the regulated tacticity of the monomer units. Co complexes and a mixture of Co and Ru complexes with carbonyl ligands promote the copolymerization of CO with propylene oxide in the presence of amine additives under CO pressure at 50 atm. Structures of the produced polyesters vary depending on the reaction conditions.     

钯催化咔唑的乙酰氧化合成新方法

本文报道了以钯（II）为催化剂的咔唑分子间直接乙酰氧基化反应的通用高效方法。以醋酸钯为催化剂,过硫酸钾为氧化剂,2-吡啶磺酰基作为导向基团,以85%和83%的收率合成单乙酰氧基化和双乙酰氧基化产物。结构经¹H NMR、¹³C NMR、IR和HR-MS(ESI)表征。      

硒催化羰基化合成苯恶唑啉酮

Benzoxazolinones are a known class of commercially available compounds that are widely used in agriculture and industry. Traditionally, these compounds are made by the intramolecular cyclization of phenyl N-(2-hydroxyphenyl)carbamate which is produced by the reaction of o-aminophenol with phenyl chloroformate[1], this route needs a large number of steps from commercially available starting materials; another method is the reaction of o-aminophenol with much more urea, a lot of NH3 is released during the process[2,3]; the last method is from salicylic acid by treatment with hydroxylamine and commercial polyphosphoric acid, the yield of the reaction is 33%[4].     

One‐Pot Direct Synthesis of Thiocarbamates from Aniline,Carbon Monoxide,and Thiols Catalyzed by Selenium

Catalyzed by selenium, oxidative carbonylation of aniline and thiols with carbon monoxide and oxygen affords the corresponding thiocarbamates mostly in moderate to good yields under solvent‐free conditions at ambient temperature.     

Palladium Catalyzed Synthesis of Fluorine-containing 3-Biaryl-1-ferrocenyl-2-propene-1-one

In the last two decades, molecular-based second-order nonlinear optical (NLO) chromo-phores1, have attracted much interest because of their potential applications in emerging 2opto-electronic technologies. These efforts have mainly focused on organic systems.More recently, organometallic molecules have been investigated as well. In comparisonto common organic molecules, they offer a large variety of novel structures3, . The 4possibility of high environmental stability, and divers…     

一种温和高效的钯催化乙炔的环三聚

乙炔是石油化工的重要产品之一,乙炔分子中存在高活性的π电子体系,具有很高的反应活性。许多催化体系包括过渡金属催化剂、非金属催化剂等可以催化活泼的乙炔发生环三聚反应,得到重要的化工原料苯。作者首次利用氯化钯作为催化剂催化乙炔环三聚,在很温和的条件下高效率地实现了这一反应。     

New Synthesis of N-Acyliminodiacetic Acid by Condensation of Amides with Formaldehyde in the Presence of Carbon Monoxide Catalyzed by Dicobalt Octacarbonyl

The synthesis of N-acyl-α-aminoacids by catalytic carbonylation of aldehydes in the presence of amides was discovered by H. Wakamatsu¹ and then investigated by P. Pino²