Diastereoselective Heterogeneous Catalytic Hydrogenation of Aromatic or Heteraromatic Compounds

The diastereoselective hydrogenation catalyzed by heterogeneous metallic catalysts uses a covalently bound chiral auxiliary to induce the chirality. It remains an active synthetic methodology in the asymmetric synthesis of chiral products and may proceed with high diastereoselectivity. This review describes recent examples using this method, such as hydrogenation of C=C, C=O, and C=N bonds. The use of a chiral auxiliary group has also been successfully applied to the hydrogenation of aromatic and heteroaromatic rings. The choice of the chiral auxiliary was found to play a key role in the asymmetric hydrogenation. The results could be explained in terms of steric effect, with a preferred conformation of the adduct substrate and the addition occurring from the less bulky side. The catalytic metal, the support and the presence of additives were also found to have a significant influence.     

多相铂催化剂在芳香族化合物加氢中的应用

介绍了负载型铂催化剂、高分子铂络合物催化剂和负载型含铂双金属催化剂等几种多相铂催化剂在芳香族化合物加氢中的应用及各自特点，展示这类催化剂在反应中具有良好的催化活性。     

Synthesis of Substituted Mandelic Acid Derivatives via Enantioselective Hydrogenation: Homogeneous versus Heterogeneous Catalysis

An extensive screening of both homogeneous and heterogeneous catalysts was carried out for the enantioselective hydrogenation of p‐chlorophenylglyoxylic acid derivatives. For p‐chlorophenylglyoxylic amides only homogeneous Rh‐diphosphine complexes gave satisfactory results, ees up to 87% were observed for the cy‐oxo‐pronop ligand. For methyl p‐chlorophenylglyoxylate both a homogeneous as well as a heterogeneous catalyst performed with ees >90%. A Pt catalyst modified with cinchona derivatives achieved 93% ee for the (R)‐ and 87% ee for the (S)‐methyl p‐chloromandelate. A Ru‐MeObiphep catalyst also reached 93% ee with TONs up to 4000 and TOFs up to 210 h⁻¹. For all catalytic systems the effects of the metal, the nature of the chiral auxiliary and the solvent as well as of the reaction conditions were investigated. The homogeneous process was scaled up to the kg scale and the enantiomeric purity of the product was enhanced to >99% ee by two recrystallizations of the free p‐chlorophenylmandelic acid.     

Convenient General Asymmetric Synthesis of Roche Ester Derivatives through Catalytic Asymmetric Hydrogenation: Steric and Electronic Effects of Ligands

An efficient and concise asymmetric hydrogenation of acrylate esters promoted by the cationic ruthenium monohydride complex [Ru(H)(η⁶‐cot)SYNPHOS]⁺BF₄⁻ is reported. A full investigation of the effects of catalyst precursors, solvents, temperature, hydrogen pressure, substrates as well as steric and electronic properties of ligands was carried out. The corresponding valuable Roche ester derivatives were obtained in good to excellent isolated yields and high enantioselectivities under mild conditions. The robustness and practicability of this highly enantioselective hydrogenation was demonstrated by the synthesis of the 3‐hydroxy‐2‐methylpropanoic acid tert‐butyl ester on a multigram scale, resulting in excellent yield and ee up to 94%.     

新型四氢异喹啉类AChE抑制剂的虚拟筛选

通过考察GOLD对已知的TcAChE复合物中配体的结合构象的重现性,评价了其对AChE体系的分子对接的可靠性。运用分子设计方法,虚拟筛选了一系列具有不同碳链长度和取代基的四氢异喹啉类化合物(延胡索类生物碱corydaline开环衍生物),并分析了得分较高的配体分子与受体蛋白的相互结合作用。     

铑催化不对称氢化反应的研究进展

综述了近几年来手性配体与铑的配合物在不对称催化氢化研究的新进展。     

Asymmetric Heterogeneous Catalysis: Science and Engineering

Asymmetric heterogeneous catalysis is a vivid branch of catalysis, remaining, however, largely a domain of organic chemists. The view towards asymmetric heterogeneous catalysis adopted in this review is mainly from catalytic science and engineering. Not only reaction mechanisms, but also catalytic properties, kinetic regularities, as well as chemical engineering aspects, are covered with the main focus on recent developments.     

Asymmetric Heterogeneous Catalysis: Science and Engineering

Asymmetric heterogeneous catalysis is a vivid branch of catalysis, remaining, however, largely a domain of organic chemists. The view towards asymmetric heterogeneous catalysis adopted in this review is mainly from catalytic science and engineering. Not only reaction mechanisms, but also catalytic properties, kinetic regularities, as well as chemical engineering aspects, are covered with the main focus on recent developments.     

Heterogeneous Hydrogenation of Vegetable Oils: A Literature Review

Hardening of vegetable oils is reviewed from an engineering point of view. The present review focuses on kinetics of the hydrogenation and relevant transport and adsorption steps. It aims to contribute to accelerate new research to improve substantially on selectivities in general and a decrease of trans fatty acid content in particular.

From a comprehensive literature review, we concluded the absence of reliable, mechanistically based kinetic rate expression. Moreover, transport limitations, both intraparticle and interfacial, cannot be excluded from the vast majority of available experimental data. Therefore, future research should focus on the development of intrinsic kinetic rate expressions, which may subsequently contribute to develop new and improved hydrogenation catalysts.     

Synthesis and SAR Studies of Isoquinoline and Tetrahydroisoquinoline Derivatives as Melatonin Receptor Ligands

In our constant search for new successors of agomelatine, we report herein a new series of compounds resulting from bioisosteric modulation of the naphthalene ring. The isoquinoline and tetrahydroisoquinoline derivatives were synthesized and pharmacologically evaluated. This isosteric replacement of the naphthalene group of agomelatine has led to potent agonist and partial agonist compounds with nanomolar melatonergic binding affinities. Overall, the presence of a nitrogen atom was accompanied with a decrease in the binding affinity toward both MT₁ and MT₂ and the loss of 5HT_2C response, especially for tetrahydroisoquinoline in comparison with the parent compound. Interestingly, due to the presence of this nitrogen atom, a notable improvement in the pharmacokinetic properties was observed for all compounds.     

多相加氢数学模型的回归

详细介绍了多相催化加氢数学模型回归的计算方法。对无副反应存在下数学模型可以处理成为线性模型进行简化,从而求得参数。但该法直接使用的dC/dt值,是使用作图镜面法获得,会引入误差。本文着重介绍使用计算机对反应数据进行dC/dt值和参数同时回归的实现方法、原理、流程,以及应用Matlab语言回归时所需的命令和求解方法。同时,该方法也可应用于多组份多副反应动力学的回归。     

Asymmetric Homogeneous Hydrogenation and Related Reactions

Following the first publication by Calvin in 1938 [1], homogeneous catalytic hydrogenation [2-5] has evolved into one of the most intensively studied branches of catalysis. This development has been supported up until now principally by the possibility this “simple” reaction offered for an understanding of some basic problems of catalysis by transition metals. In fact, homogeneous catalytic hydrogenation by transition metal complexes has possibly become the theoretically and mechanistically best known catalytic reaction of this sort.     

Under Pressure: Rapid Development of Scalable Asymmetric Hydrogenation Catalysts

Catalytic asymmetric hydrogenation is arguably one of most efficient methods of choice to synthesize a stereogenic center. The time to market pressure and the wide diversity of possible compounds require a flexible and rapid approach to implement technology. The automated synthesis and screening protocol of monodentate ligands, developed at DSM, provides such a technology. Applications of this, so-called, MonoPhos^TM ligand library in Rh- and Ir-catalyzed asymmetric hydrogenations have led to cost-effective productions of intermediates for several drugs, such as Aliskiren. A new bulky phosphite ligand has been identified performing particularly well for the asymmetric hydrogenation of the sterically demanding enamide 5.     

Asymmetric Synthesis of the Roche Ester and its Derivatives by Rhodium‐INDOLPHOS‐Catalyzed Hydrogenation

(S)‐3‐Hydroxy‐2‐methylpropionate, known as the Roche ester, and several of its derivatives were successfully synthesized through asymmetric rhodium‐catalyzed hydrogenation, using INDOLPHOS (diisopropyl{1‐[(S)‐3,5‐dioxa‐4‐phosphacyclohepta[2,1‐a;3,4‐a′]dinaphthalen‐4‐yl]‐3‐methyl‐2‐indolyl}phosphine) as the chiral ligand, in excellent yield and the highest ee reported up to now (TOF over 5500 h⁻¹ at 25 °C; up to 98% ee at −40 °C).     

不对称催化加氢的研究进展

叙述了不对称催化加氢的研究进展,分别对均相、多相不对称催化氢化以及均相催化剂的多相化进行了介绍,评述了均相、非均相不对称催化加氢的优缺点,提出了不对称催化加氢未来发展的方向和需要解决的问题,即一是如何得到更好的对映选择性,二是如何使催化剂具有更好的重复性。     

多相催化加氢动力学方程的建立与推导

在化学实验放大到生产装置过程中,催化反应动力学的研究具有十分重要的意义。详细介绍了多相催化加氢动力学方程的建立与推导过程,通过可能存在的反应机理,按照Langmuir吸附等温方程和决速步假设,建立并推导可能存在的反应方程,以便于按照这些方程对反应数据进行回归分析,得到可能的反应方程以推测出可能的反应机理。同时,还列举了一些已被证实的反应速率模型。     

DuPHOS在不对称催化氢化中的研究进展

介绍了一种新颖的具有C2对称性的手性双磷杂环戊烷配体DuPHOS，此配体在烯酰胺类、2－烷基琥珀酸类、α－羟基醌类、开链烯醇酯类、酮类等众多类型底物的不对称催化氢化反应中显示出了极高的对映体选择性，本文对此配体的最新研究进展进行了综述。