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1.
Lars A. Leth Dr. Florian Glaus Dr. Marta Meazza Dr. Liang Fu Mathias K. Thøgersen Emma A. Bitsch Prof. Dr. Karl Anker Jørgensen 《Angewandte Chemie (International ed. in English)》2016,55(49):15272-15276
A novel reaction based on synergistic catalysis, combining palladium‐ and organocatalysis has been developed. The palladium catalyst activates vinyl benzoxazinanones via a decarboxylation to undergo a [4+2] cycloaddition with iminium‐ion activated α,β‐unsaturated aldehydes. The reaction is demonstrated to proceed for a number of combinations of vinyl benzoxazinanones reacting with α,β‐unsaturated aldehydes, providing highly substituted vinyl tetrahydroquinolines in good to high yields, and excellent enantio‐ and diastereoselectivities (>98 % ee and >20:1 d.r.). The palladium catalyst used in the synergistic catalysis can be re‐used in a one‐pot sequential coupling reaction with an aromatic boronic acid forming the coupling product in 95 % yield, >20:1 d.r. and 99 % ee. 相似文献
2.
Hua-Chao Liu Yuan-Zheng Hu Zuo-Fei Wang Hai-Yan Tao Prof. Dr. Chun-Jiang Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(37):8681-8685
An unprecedented asymmetric allenylic alkylation of readily available imine esters, which was enabled by a synergistic Cu/Pd catalysis, has been developed. This dual catalytic system possesses good substrate compatibility, delivering a diverse array of nonproteinogenic α-allenylic α-mono- or α,α-disubstituted α-amino acids (α-AAs) with high yields and generally excellent enantioselectivities. Furthermore, the scalability and practicability of the current synthetic protocol were proven by performing gram-scale reactions and by the first catalytic asymmetric synthesis of naturally occurring (S)-γ-allenic α-amino acid, respectively. 相似文献
3.
Jacqkis Davis Mojgan Gharaee Dr. Chamini V. Karunaratne Jose Cortes Vazquez Mikayla Haynes Prof. Weiwei Luo Dr. Vladimir N. Nesterov Prof. Thomas Cundari Prof. Hong Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(27):e202200224
Cooperative enamine-metal Lewis acid catalysis has emerged as a powerful tool to construct carbon-carbon and carbon-heteroatom bond forming reactions. A concise synthetic method for asymmetric synthesis of chromans from cyclohexanones and salicylaldehydes has been developed to afford tricyclic chromans containing three consecutive stereogenic centers in good yields (up to 87 %) and stereoselectivity (up to 99 % ee and 11 : 1 : 1 dr). This difficult organic transformation was achieved through bifunctional enamine-metal Lewis acid catalysis. It is believed that the strong activation of the salicylaldehydes through chelating to the metal Lewis acid and the bifunctional nature of the catalyst accounts for the high yields and enantioselectivity of the reaction. The absolute configurations of the chroman products were established through X-ray crystallography. DFT calculations were conducted to understand the mechanism and stereoselectivity of this reaction. 相似文献
4.
Enantioselective α‐Alkylation of Aldehydes by Photoredox Organocatalysis: Rapid Access to Pharmacophore Fragments from β‐Cyanoaldehydes
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Eric R. Welin Dr. Alexander A. Warkentin Dr. Jay C. Conrad Prof. Dr. David W. C. MacMillan 《Angewandte Chemie (International ed. in English)》2015,54(33):9668-9672
The combination of photoredox catalysis and enamine catalysis has enabled the development of an enantioselective α‐cyanoalkylation of aldehydes. This synergistic catalysis protocol allows for the coupling of two highly versatile yet orthogonal functionalities, allowing rapid diversification of the oxonitrile products to a wide array of medicinally relevant derivatives and heterocycles. This methodology has also been applied to the total synthesis of the lignan natural product (?)‐bursehernin. 相似文献
5.
Azomethine ylides are useful intermediates for the rapid construction of chiral N‐containing compounds. However, its synthetic potential has not been fully developed due to the limited reaction models. In combination with synergistic catalysis and azomethine ylide chemistry, we have developed several types of novel catalytic system including Cu/Pd, Cu/Ir and PTC/Ir catalysis, which can convert readily‐available azomethine ylides to various high‐valued molecules such as unnatural α‐amino acids, homoallylic amines and N‐heterocycles. Compared with the traditional mono‐catalysis, the synergistic catalyst system exhibits enhanced catalytic efficiency and chiral induction ability in many cases. In addition, we have demonstrated that these strategies could be applied in the construction of bioactive compounds and natural products. 相似文献
6.
Yue Wu Prof. Xiaohong Huo Prof. Wanbin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(22):4895-4916
Synergistic Pd/Cu catalysis has been utilized in the Sonogashira reaction since 1975. However, this strategy has not received much attention from the organic chemist community until recently. Synergistic Pd/Cu catalysis is becoming a proficient method for the development of catalytic reactions, including several new and efficient cross-coupling reactions. Additionally, several challenging asymmetric reactions, including stereodivergent synthesis, have been discovered by the combined use of a chiral metal catalyst and a second achiral metal catalyst or two chiral metal catalysts. This review provides an overview of this field, with the aims of highlighting both the development of synergistic Pd/Cu catalysis in organic synthesis and the reaction mechanisms involved in this research area. 相似文献
7.
Wei‐Long He Min Zhao Chuan‐De Wu 《Angewandte Chemie (International ed. in English)》2019,58(1):168-172
Even though numerous bioinspired catalysts have been developed, there remain huge gaps between the artificial and natural catalysts, because it is very difficult to imitate simultaneously the complicated constituents, structures, and synergistic effect of enzymes. We report herein a versatile metalloporphyrinic framework platform, which exhibits high efficiency in bioinspired catalysis, photocatalysis, and asymmetric catalysis. The catalytic properties are highly dependent on the tunable constituents and their cooperation, and are significantly superior to the corresponding molecular catalyst systems which lack the synergistic effects. Since there are numerous functional moieties that can readily be incorporated into the metalloporphyrinic framework platform, a myriad of applications can be simply realized by embedding different functional moieties. 相似文献
8.
9.
Trio Catalysis Merging Enamine,Brønsted Acid,and Metal Lewis Acid Catalysis: Asymmetric Three‐Component Aza‐Diels–Alder Reaction of Substituted Cinnamaldehydes,Cyclic Ketones,and Arylamines
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Dr. Yongming Deng Siddhartha Kumar Prof. Kraig Wheeler Prof. Hong Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(21):7874-7880
A trio catalyst system, composed of arylamine, BINOL‐derived phosphoric acid, and Y(OTf)3, enables the combination of enamine catalysis with both hard metal Lewis acid catalysis and Brønsted acid catalysis for the first time. Using this catalyst system, a three‐component aza‐Diels–Alder reaction of substituted cinnamaldehyde, cyclic ketone, and arylamine is carried out with high chemo‐ and enantioselectivity, affording a series of optically active 1,4‐dihydropyridine (DHP) derivatives are obtained in 91–99 % ee and 59–84 % yield. DHPs bearing a chiral quaternary carbon center are also obtained with good enantioselectivity and moderate yield (three examples). Preliminary mechanistic investigations have also been conducted. 相似文献
10.
Direct Allylation of In Situ Generated Aldehyde Acyl Anions by Synergistic NHC and Palladium Catalysis
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Milind M. Ahire Dr. Santosh B. Mhaske 《Angewandte Chemie (International ed. in English)》2014,53(27):7038-7042
The direct regioselective allylation of in situ generated aldehyde acyl anions has been achieved by synergistic NHC and Pd catalysis. It provides an efficient access to valuable β,γ‐unsaturated ketones under mild reaction conditions starting from easily accessible allylic carbonates and aldehydes without any preactivation. The synergistic catalysis method demonstrated herein adds a new dimension to the area of metal‐mediated C allylation. 相似文献
11.
Catalysis is one of the key techniques for people's modern life. It has created numerous essential chemicals such as biomedicines, agricultural chemicals and unique materials. Heterogeneous catalysis is the new emerging method with reusable catalysts. Among heterogenous catalysis patterns developed so far, single crystalline catalysis has become the promising one owing to its high catalytic density and selectivity resulted by the inherent porosity, orderliness of the lattices and permeability. These crystalline catalysts could be used in various reactions such as photo-dimerization, Diels-Alder reaction, CO2 transformation and so on. In this review, we highlighted the reported works about the single crystalline catalysts. Both discrete small molecules and metal-organic frameworks (MOFs) have been used to prepare single crystals for catalysis. For discrete molecules based crystalline catalysts, coordinated and covalent molecules have been used. There were more catalytic modes in crystalline MOF catalysts. Three patterns were identified in this review: single crystalline MOFs i) without catalytic sites, ii) with inherent catalytic features and iii) with introducing catalytic units by post synthetic modification. Based on these examples, this review committed to provide the inspirations for the further design and application of single crystalline materials. 相似文献
12.
Tianhong Wang Youbin Peng Guanlin Li Yicong Luo Yong Ye Dr. Xiaohong Huo Prof. Wanbin Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(40):10255-10260
3,3-Disubstituted oxindoles bearing quaternary and tertiary stereogenic centers are privileged structural motifs, which widely exist in pharmaceutical and natural products. Herein, a highly regio-, enantio-, and diastereoselective allylic alkylation of 3-alkyl oxindoles through synergistic iridium and copper catalysis is described, which provides a series of 3,3-disubstituted oxindole derivatives containing adjacent quaternary and tertiary stereogenic centers in excellent yields, enantiomeric excess, and diastereomeric ratio (for 30 examples, up to 97 % yield, >99 % ee, and >20 : 1 dr). This method provides exclusive branched selectivity, excellent enantio- and diastereoselectivities, and good functional compatibility. Control experiments suggested that the chiral copper catalyst is required for achieving high reactivities and diastereoselectivities under mild reaction conditions. 相似文献
13.
研究了双酸催化剂不对称催化烯醚和β,γ-不饱和α-酮酸酯的反电子Hetero-Diels-Alder (HDA)反应, 为手性合成3,4-二氢-2H-吡喃类化合物提供了一种新的催化合成方法. InBr3与手性磷酸钙盐Ca(1c)2组合的手性双路易斯酸催化体系能够有效催化3,4-二氢-2H-吡喃和β,γ-不饱和α-酮酸酯的反电子HDA反应, 反应给出优秀的产率(最高达98%), 中等到良好的非对映选择性(最高达89:11)和良好到优秀的对映选择性(最高可达94%). 并且该双酸催化体系也能成功实现其它烯醚(如: 2,3-二氢-2H-呋喃, 乙烯基乙醚)的HDA反应, 获得优秀的非对映选择性(>94:6)和良好的对映选择性. 相似文献
14.
Dr. Chao Liu Zhensheng Chen Kaixuan Teng Dr. Wangshu Tong Prof. Yihe Zhang Whowwei Chee Prof. Qi An 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(15):e202104287
The molecularly selective catalysis in enzyme is central to life. However, their functioning mechanism remains elusive. We propose here that the synergistic effects from (i) effective orbital hybridizing and energy gap decreasing via chelating on single Zr atom as the catalytic center, (ii) selective supramolecular encapsulation in the cage, and (iii) piezoelectrical field motivation are able to achieve the enzyme-mimetic molecular selective high performance catalysis. Metal–organic polyhedra (MOPs) are added into a piezoelectrical polymer matrix to achieve the composite structure where ultrasonic treatment motivates redox reactions in the MOP-guest complex. Encapsulated and chelated guest such as Rhodamine B (RhB) is effectively converted with ratios higher than 90 % after 100 min. In comparison, molecules inefficient in either cage encapsulation or chelating with the Zr center can not be converted. This study first proposes a synergistic plot for enzyme-mimetic catalyst realization and is expected to inspire new mentality in efficient catalyst designing. 相似文献
15.
Combined Heterogeneous Metal/Chiral Amine: Multiple Relay Catalysis for Versatile Eco‐Friendly Synthesis
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Dr. Luca Deiana Dr. Yan Jiang Dr. Carlos Palo‐Nieto Samson Afewerki Celia A. Incerti‐Pradillos Dr. Oscar Verho Dr. Cheuk‐Wai Tai Dr. Eric V. Johnston Prof. Armando Córdova 《Angewandte Chemie (International ed. in English)》2014,53(13):3447-3451
Herein is described a versatile and broad synergistic strategy for expansion of chemical space and the synthesis of valuable molecules (e.g. carbocycles and heterocycles), with up to three quaternary stereocenters, in a highly enantioselective fashion from simple alcohols (31 examples, 95:5 to >99.5:0.5 e.r.) using integrated heterogeneous metal/chiral amine multiple relay catalysis and air/O2 as the terminal oxidant. A novel highly 1,4‐selective heterogeneous metal/amine co‐catalyzed hydrogenation of enals was also added to the relay catalysis sequences. 相似文献
16.
甲烷合成甲醇的方法包括间接法和直接催化氧化(DMTM)法,但是间接法对设备要求高,且甲烷转化率与甲醇选择性均不理想,DMTM法可通过一步反应高选择性制备甲醇,有巨大的应用潜力。对于甲烷DMTM法合成甲醇,均相催化体系通常需要特殊反应介质与贵金属催化剂相结合,虽然反应效率高,但对反应设备有腐蚀性,产物不易分离,应用前景差。液相-异相催化一般使用H_(2)O_(2)作为氧化剂,Au、Pd、Fe和Cu等金属元素作为催化剂主要活性组分,·OH是主要的氧化活性物,可在低温下实现甲烷的活化氧化。因此,异相催化体系是目前研究的主流。气相-异相催化主要使用O_(2)和N_(2)O为氧化剂,前者氧化性更强,后者对于产品选择性更好,此外,厌氧体系中H_(2)O也可直接作为氧供体,常用Cu、Fe、Rh等元素作为催化剂。沸石分子筛是使用最广泛的载体,金属氧化物、金属有机骨架化合物(MOFs)和石墨烯也均有涉及,多金属协同催化已经取得了很好的效果。本文主要总结与概述了热催化甲烷直接催化氧化制备甲醇的近年相关研究,并对今后的研究方向做出了展望。 相似文献
17.
Dr. Antonio Del Vecchio Arianna Sinibaldi Valeria Nori Giuliana Giorgianni Dr. Graziano Di Carmine Dr. Fabio Pesciaioli 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(49):e202200818
Synergistic catalysis offers the unique possibility of simultaneous activation of both the nucleophile and the electrophile in a reaction. A requirement for this strategy is the stability of the active species towards the reaction conditions and the two concerted catalytic cycles. Since the beginning of the century, aminocatalysis has been established as a platform for the stereoselective activation of carbonyl compounds through HOMO-raising or LUMO-lowering. The burgeoning era of aminocatalysis has been driven by a deep understanding of these activation and stereoinduction modes, thanks to the introduction of versatile and privileged chiral amines. The aim of this review is to cover recent developments in synergistic strategies involving aminocatalysis in combination with organo-, metal-, photo-, and electro-catalysis, focusing on the evolution of privileged aminocatalysts architectures. 相似文献
18.
《Electroanalysis》2006,18(22):2251-2256
In this paper, photoelectro‐synergistic catalysis oxidation of organics in water on Ti/TiO2/PbO2 electrode was investigated by the method of electrochemistry. Furthermore, the results were compared with those obtained from photocatalysis and electrocatalysis. The method proposed was applied to determine the chemical oxygen demand (COD) value, Ti/TiO2/PbO2 electrode functioning as the work electrode during the process. It was shown that the method of photoelectro‐synergistic catalysis had lower detection limit and wider linear range than the methods of electroassisted photocatalysis and electrocatalysis. The results obtained by the proposed method and conventional one were compared by carrying out the experiment on 8 wastewater samples. The correlation of the results using different methods was satisfactory and the relative bias was below ±6.0%. 相似文献
19.
A synergistic catalysis combination of chiral‐at‐metal rhodium complex and amine catalyst was developed for enantioselective alkylation of aldehydes with α,β‐unsaturated 2‐acyl imidazoles. The corresponding adducts were obtained in good yields with excellent enantioselectivities (up to 99% ee). 相似文献
20.
The synergistic effect between metal and TiO2 nanoparticles brings about new, enhanced functionalities for a myriad of applications, ranging from labeling and sensing to catalysis and surface‐enhanced Raman scattering. Although extensive work has been done in the preparation of concentric TiO2‐coated metal nanostructures, current methods for the synthesis of noncentrosymmetric morphologies are still very limited. This Focus review summarizes the various methods used to prepare TiO2‐coated metal nanostructures, with a particular emphasis on noncentrosymmetric morphologies, their novel plasmonic properties, and their promising applications in the fields of catalysis and photocatalysis. 相似文献