纯水中有氧条件下Pd/C催化的无配体Suzuki反应简

报道一种在纯水中Pd/C催化的高效Suzuki反应体系,该体系无需除氧,且无外加配体和添加剂,底物普适性广泛,含有亲水或疏水基团的溴代芳烃都能被高效活化. 此外,对部分杂环芳烃与芳基硼酸的偶联反应也有较好的催化效果. 该催化剂可高效循环使用三次,且性能无明显下降.     

Oxygen-promoted Pd/C-catalyzed Suzuki–Miyaura reaction of potassium aryltrifluoroborates

A simple and highly efficient protocol has been developed for the Pd/C-catalyzed ligand-free Suzuki–Miyaura reaction of potassium aryltrifluoroborates. In this catalytic system, the results demonstrate that oxygen plays a positive role in the cross-coupling reaction. In addition, this catalytic system could be successfully applied to synthesize biaryl compounds containing a carbazole moiety and the catalyst was recycled seven times without significant loss of catalytic activity.     

Rhodium-terpyridine Catalyzed Transfer Hydrogenation of Aromatic Nitro Compounds in Water

A rhodium terpyridine complex catalyzed transfer hydrogenation of nitroarenes to anilines with i-PrOH as hydrogen source and water as solvent has been developed. The catalytic system can work at a substrate/catalyst (S/C) ratio of 2000, with a turnover frequency (TOF) up to 3360 h⁻¹, which represents one of the most active catalytic transfer hydrogenation systems for nitroarene reduction. The catalytic system is operationally simple and the protocol could be scaled up to 20 gram scale. The water-soluble catalyst bearing a carboxyl group could be recycled 15 times without significant loss of activity.     

Highly efficient catalytic aerobic oxidations of benzylic alcohols in water

A highly efficient catalytic system without transition metals in water has been developed for aerobic oxidations of benzylic alcohols. The newly developed catalyst system could oxidize benzylic alcohols and heteroaromatic analogues with 1 mol % TEMPO as a catalyst and with a catalytic amount of 1,3-dibromo-5,5-dimethylhydantoin and NaNO2 as cocatalysts. Under the optimal conditions, various alcohols could be converted into their corresponding aldehydes or ketones in high yields.     

From CO oxidation to CO2 activation: an unexpected catalytic activity of polymer-supported nanogold

A simple, clean, safe, and reproducible catalyst system, polymer-supported nanogold, was successfully developed for the fixation of CO2 to cyclic carbonate and for the carbonylation of amines to disubstituted ureas with unprecedented catalytic activity (TOF > 50 000 mol/mol/h and TOFP approximately 3000 mol/mol/h, respectively). To the best of our knowledge, it was the first to report that nanogold catalysts have exclusive catalytic activity for activation of carbon dioxide, and that the catalytic activity of the polymer-immobilized nanogold catalysts could be controlled by the particle size of the nanogold.     

An efficient aerobic oxidative phosphonation of a-amino CH bonds over CoNiFe hydrotalcite

An efficient and convenient heterogeneous catalytic procedure has been developed for the phosphonation of a-amino CH bonds with various dialkyl phosphites and diarylphosphine oxides using molecular oxygen as a sustainable oxidant over CoNiFe hydrotalcite. The catalytic system could tolerate various tetrahydroquinoline derivatives, and the corresponding a-amino phosphonic compounds could be obtained in good to excellent yields. Synergistic effect might exist in the oxidative phosphonation under the catalysis of CoNiFe hydrotalcite.     

Synergistic Catalysis with Azomethine Ylides

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.     

An improved catalytic system for recycling OsO4 and chiral ligands in the asymmetric dihydroxylation of olefins

A recyclable catalytic system for the asymmetric dihydroxylation of olefins was developed by using a mono-quaternized bis-cinchona alkaloid ligand 3 and OsO₄ combined with PEG or an ionic liquid. Both the catalytic components could be recovered and reused in five consecutive reactions without any additional OsO₄ or ligand. The catalytic system is effective in the AD reactions of seven olefins.     

Heck and Sonogashira cross-coupling reactions using recyclable Pd–Fe3O4 heterodimeric nanocrystal catalysts

We have developed a convenient Pd–Fe₃O₄ heterodimeric nanocrystal catalyst system for Heck and Sonogashira reactions. This catalyst offers an environment-friendly, atom-efficient, and robust catalytic system for both reactions. Furthermore the nanocrystal catalyst could be easily separated by an external magnet and recycled six times without losing its catalytic activity.     

Recyclable and reusable Pd(OAc)2/DABCO/PEG-400 system for Suzuki-Miyaura cross-coupling reaction

[reaction: see text] A stable and efficient Pd(OAc)2/DABCO (triethylenediamine) catalytic system for Suzuki-Miyaura cross-coupling reaction has been developed. In the presence of Pd(OAc)2 and DABCO, coupling of aryl halides with arylboronic acids was carried out smoothly to afford good to excellent yields and high turnover numbers (TONs) (the maximal TONs were up to 960,000 for the reaction of 1-iodo-4-nitrobenzene with phenylboronic acid) using PEG-400 as the solvent. Moreover, the Pd(OAc)2/DABCO/PEG-400 system could be recycled and reused five times without any loss of catalytic activity for aryl iodides and bromides.     

室温离子液体中催化合成肉桂酸苄酯

研究离子液体中肉桂酸钾和氯化苄经缩合合成肉桂酸苄酯的新方法,并对多种离子液体的作用性能进行了考察.研究结果表明,离子液体中BMImBF4的催化性能最佳,但是肉桂酸苄酯的收率仍不高,只有当相转移催化剂四丁基氯化铵存在时,肉桂酸钾与溶于离子液体中的氯化苄在温和的反应条件下才可高效率地得到肉桂酸苄酯,收率可达96.5%.产物分离简单,离子液体和相转移催化剂形成的双催化体系可以稳定地循环使用5次以上.     

Pd-catalyzed intramolecular Heck reaction for the synthesis of 2-methylbenzofurans

A new strategy for the synthesis of 2-Methylbenzofurans via the intramolecular Heck reaction has been developed. This efficient palladium-catalyzed system showed good catalytic activity. Various substituted 2-methylbenzofurans could be afforded in good to excellent yields.     

Aerobic oxidative dehydrogenation of N-heterocycles catalyzed by cobalt porphyrin

An efficient catalytic procedure has been developed for the aerobic oxidative dehydrogenation of N-heterocycles by cobalt porphyrin in the absence of any additives. The catalytic system could tolerate various 1,2,3,4-tetrahydroquinoline derivatives and some other N-heterocycles. The corresponding N-heteroaromatics could be obtained in 59–86% yields. The mechanism investigation suggested that the aerobic oxidative dehydrogenation might proceed with imine intermediate through radical paths.     

Aerobic alcohol oxidation using a PdCl2/N,N-dimethylacetamide catalyst system under mild conditions

A new and simple PdCl₂/DMA catalytic system for the alcohol oxidation has been developed using molecular oxygen as the sole oxidant under mild conditions. The catalytic system could be reused for three runs without significant loss of catalytic activity. A variety of active and non-active alcohols were oxidized to their corresponding carbonyl compounds in good to excellent yields. Gas-uptake kinetics for the catalytic system was also investigated. The ca. 1:1 molar ratio of O₂ uptake to product yield is observed, suggesting the in situ formation of H₂O₂.     

A pH-responsive TiO2-based Pickering emulsion system for in situ catalyst recycling

Through tuning the surface wettability of interfacially active TiO₂ particles, a pH-responsive Pickering emulsion system is formed, as in situ separation and recycling of the nano-catalysts system.     

Robust Acenaphthoimidazolylidene Palladacycles: Highly Efficient Catalysts for the Amination of N‐Heteroaryl Chlorides

A series of robust N‐heterocyclic carbene palladacycles have been successfully developed. These showed high catalytic activity and selectivity toward the challenging amination of N‐heteroaryl chlorides. Different primary and secondary amines were fully compatible with this catalytic system. Remarkably, no double amination products could be detected when primary amines were utilized in our catalytic transformation. Furthermore, the protocol has been successfully extended to synthesize rosiglitazone, a clinical drug for diabetes mellitus, highlighting its potential pharmaceutical feasibility.     

Imidazolium-based polymer supported gadolinium triflate as a heterogeneous recyclable Lewis acid catalyst for Michael additions

A heterogeneous Lewis acid catalytic system has been developed by incorporating gadolinium triflate on to poly[styrene-co-(1-((4-vinylphenyl)methyl)-3-methylimidazolium) tetrafluoroborate] (1-Gd(OTf)₃), and the catalytic activity of this system has been examined for Michael additions of amines and thiols to α,β-unsaturated esters and acrylonitrile. The reactions proceed in moderate to excellent yields in the presence of catalytic system 1-Gd(OTf)₃. The catalytic system could be efficiently recycled and reused.     

Selective aerobic oxidation of activated alcohols into acids or aldehydes in ionic liquids

Selective aerobic oxidation of activated primary alcohols into acids or aldehydes has been developed in ionic liquids. Under optimal conditions, various alcohols could be selectively converted into their corresponding acids or aldehydes in good to excellent yields. The newly developed catalytic systems could also be recycled and reused for three runs without any significant loss of catalytic activity.     

A free radical process for oxidation of hydrocarbons promoted by nonmetal xanthone and tetramethylammonium chloride under mild conditions

A nonmetal catalytic system consisting of N-hydroxyphthalimide, xanthone, and tetramethylammonium chloride was developed. A wide range of hydrocarbons could be oxidized efficiently with dioxygen under mild conditions. In the presence of xanthone and tetramethylammonium chloride, catalytic activity of N-hydroxyphthalimide was greatly improved, and selectivity for alkyl hydroperoxide was remarkably decreased.     

CuI/8‐Hydroxyquinalidine Promoted N‐Arylation of Indole and Azoles

An efficient catalytic system of CuI/8‐hydroxyquinalidine was developed for the coupling of aryl iodides and indole as well as some azoles. The reaction could be carried out at 90°C under the condition of relatively low catalyst loading, affording various N‐arylindoles and N‐aryl azoles in good yields. The functionalized and hindered aryl iodides were suitable substrates for this transformation.