A novel one-pot synthesis of carbazole-1,4-quinones through Pd-catalyzed cyclocarbonylation,desilylation and oxidation processes from 3-iodo-2-propenylindoles

A novel one-pot synthesis of carbazole-1,4-quinone by consecutive Pd-catalyzed cyclocarbonylation, desilylation, and oxidation reactions is described. We propose a possible mechanism of the cyclocarbonylation reaction between 3-iodo-2-propenylindole and CO (1 atm) in the presence of a tributyl(vinyl)tin and Pd-catalyst and the resulting acylpalladium species was directly coupled with a terminal alkene to produce the carbazole-1,4-quinone. To our knowledge, this is the first example of this type of reaction. A new formal total synthesis of a carbazole-1,4-quinone alkaloid, murrayaquinone A was established using this reaction.     

A simple catalytic system based on PdCl2(CH3CN)2 in water for cross-coupling reactions using diazonium salts

Aryl–heteroaryl and heteroaryl–heteroaryl compounds are obtained through the Suzuki–Miyaura cross-coupling reactions between diazonium salts and potassium trifluoroborates using PdCl₂(CH₃CN)₂ as the catalyst in water and in the absence of any additive, ligand or base. In addition, the same mild catalytic system is effective for the Matsuda–Heck reaction between several monoolefins with aryldiazonium salts.     

4-Dimethylaminopyridine-catalyzed multi-component one-pot reactions for the convenient synthesis of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives

An efficient and clean reaction process was developed for the convenient and cheap synthesis of spirooxindole derivatives. One-pot reactions of isatins, malononitrile (or ethyl cyanoacetate), hydrazine hydrate (or phenylhydrazine), and 1,3-dicarbonyl compounds were compared with one-pot reactions of isatins, malononitrile (or ethyl cyanoacetate), and 5-pyrazolone derivatives. Both sets of reaction were conducted in EtOH in the presence of 4-DMAP catalyst. A series of spiro[indoline-3,4′-pyrano[2,3-c]pyrazole] derivatives were quickly obtained in excellent yields by using the four-component one-pot reaction method.     

Solar thermochemical reactionsⅢ:A convenient one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles catalyzed by high surface area SiO_2 and induced by solar thermal energy

A simple,convenient and efficient method for the synthesis of 1,2,4,5-tetrasubstituted imidazole derivatives using benzoin,an aromatic aldehyde,an aromatic amine in the presence of ammonium acetate catalyzed by high surface area SiO_2 and induced by free solar thermal energy was reported.     

2-Ethoxy-3-pyridylboronic acid: a versatile reagent for the synthesis of highly-functionalised 3-aryl/heteroaryl-pyridines via Suzuki cross-coupling reactions

This paper describes the commercially-viable synthesis and isolation of 2-ethoxy-3-pyridylboronic acid on a ca. 70 g scale via a directed ortho-metalation reaction on readily-available 2-ethoxypyridine. A range of efficient cross-coupling reactions of 2-ethoxy-3-pyridylboronic acid with selected aryl/heteroaryl halides under palladium-catalysed Suzuki-Miyaura conditions yield novel 2-ethoxy-3-aryl/heteroaryl-pyridines in high yield (heteroaryl=pyridyl, pyrimidyl, pyrazyl). The X-ray crystal structure of 2-ethoxy-3-pyridylboronic acid reveals that the boronic acid group takes part in an intramolecular O-H?O bond with the adjacent ethoxy substituent, and an intermolecular O-H?N bond.     

KF-Al~2O~3试剂在有机合成反应中的应用进展

综述了自1979年Yamawaki和Ando发现KF-Al~2O~3试剂的催化特性以来在有机合成反应中的应用研究进展。     

Palladium-catalyzed one-pot synthesis of benzo[b][1,6]naphthyridines via Sonogashira coupling and annulation reactions from 2-chloroquinoline-3-carbonitriles

Palladium-catalyzed one-pot synthesis of 1,3-disubstituted benzo[b][1,6]naphthyridines and [1,6]naphthyridines has been described from easily accessible precursors, 2-chloroquinoline-3-carbonitriles and 2-chloropyrido-3-carbonitrile via sequential additions of palladium-catalyst for Sonogashira-coupling and the following annulations in good to excellent yields. A plausible mechanism for annulation is discussed.     

金催化的环化反应与钯催化的炔醇偶联/环化反应相结合用于合成多取代呋喃衍生物:串联反应的应用范围(英文)

开发了一种由金和钯催化π-活化由炔醇合成呋喃衍生物的集成方法.该合成策略是最显著的特点适用于带环辛基的底物,其适用范围比之前报道的有很大扩展.在Sonogashira反应条件下,由相应底物可直接得到环辛基呋喃.Pd在这些反应中起到2个重要作用:底物发生偶联反应的关键催化剂;通过π-活化促进炔醇中间体成环反应.该方法在一步合成3-碘呋喃反应中作用很突出,使通过偶联法进一步官能团化成为可能.我们还将AuBr_3用于多米诺成环/C-H键活化反应和无环前体的成环反应.本文结果表明,在该类成环反应中金和钯催化剂相辅相成.     

Synthesis of 3-substituted indazoles and benzoisoxazoles via Pd-catalyzed cyclization reactions: application to the synthesis of nigellicine

Syntheses of 3-substituted indazoles and benzoisoxazoles were efficiently accomplished with the aid of Pd-catalyzed intramolecular carbon-nitrogen and carbon-oxygen bond formations. The catalyst system described herein allows the cyclization to proceed under very mild conditions and thus could be applied to a wide range of substrates with acid- or base-sensitive functional groups. A total synthesis for the indazole ring-containing natural product nigellicine is also described.     

A modified procedure for the Dakin-West reaction: an efficient and convenient method for a one-pot synthesis of β-acetamido ketones using silica sulfuric acid as catalyst

A one-pot, four-component condensation of an aryl aldehyde, an aryl ketone, acetyl chloride and acetonitrile in the presence of silica sulfuric acid as an active, inexpensive, recoverable and recyclable catalyst is disclosed for the synthesis of β-acetamido ketones.     

A convenient and efficient one pot synthesis of unsymmetrically substituted p-terphenyls via a phosphine-free double Suzuki cross-coupling protocol using 1,4-dibromo-2-nitrobenzene as the substrate

A synthetic procedure has been developed to enable the sequential regio-selective Suzuki-Miyaura cross-coupling of 1,4-dibromo-2-nitrobenzene with a variety of arylboronic acids. The first Suzuki coupling step, using a phosphine-free palladium catalyst at room temperature, gave selective coupling at the position ortho to the nitro group, opening a convenient synthetic route to unsymmetrical para-terphenyls. The bromobiaryl product was then subjected directly to the second coupling step, in situ, using preferred aryl-boronic acids to give by this one-pot batch procedure unsymmetrically substituted para-terphenyls in excellent overall isolated yields. This methodology should be particularly suited for the generation of targeted chemical libraries, as well as for the synthesis of precursors of biologically active compounds or natural products which are derived from the unsymmetrical para-terphenyl core.     

A Straightforward Method for the Synthesis of Functionalized Trisubstituted Alkenes through Na2S/Al2O3 Catalyzed Knoevenagel Condensation

Na₂S/Al₂O₃ catalyzed the Knoevenagel condensation between an aldehyde and an active methylene compound to yield various trisubstituted alkenes.     

Stereoselective synthesis of spirocyclic oxindoles based on a one-pot Ullmann coupling/Claisen rearrangement and its application to the synthesis of a hexahydropyrrolo[2,3-b]indole alkaloid

An efficient and convenient approach to the synthesis of spirocyclic oxindoles from iodoindoles has been developed. The most striking feature of this approach is that the sequential intramolecular Ullmann coupling and Claisen rearrangement proceeds in a one-pot manner to afford 3-spiro-2-oxindoles in good yield with excellent diastereoselectivity. Application of this one-pot reaction to chiral non-racemic tertiary alcohol substrates resulted in complete chirality transfer to the spirocyclic quaternary carbon. Using this method, asymmetric total synthesis of (−)-debromoflustramine B was accomplished.     

一锅法制备1T/2H-WS2/WO3异质结用于紫外可见光催化的CO2还原

采用一锅水热法制备了1T/2H-WS2/WO3异质结，并利用XRD、SEM、XPS等对所制备的光催化材料进行了系统微结构表征。研究发现该异质结催化剂可以水蒸汽作为电子供体，利用可见光催化还原CO2，以3.87 μmol g-1 h-1的速率高选择性的生成唯一产物CO。在紫外-可见光辐照下，表现出更优异的催化活性（34.39 μ mol g-1 h-1）。经4次循环实验，仍然表现出稳定的光催化二氧化碳还原效率，证明其具有优异的稳定性。     

A carrier-free and recyclable protocol for the cross-coupling of terminal alkynes with arylboronic acids in H2O/TBAB

A new and recyclable protocol was developed for Pd(OAc)₂-catalyzed the cross-coupling reaction of terminal alkynes with arylboronic acids using environmentally friendly H₂O/TBAB as reaction medium. A series of cross-coupling products containing internal acetylenic bond can be obtained with good selectivity and yield. The Pd(OAc)₂/H₂O/TBAB system was stable in the Sonogashira-type cross-coupling reaction and could be used at least three cycles without considerable decrease in catalytic performance. The results suggest that the unsupported and recyclable systems can be extended to the other realm of CC bond formation in synthetic organic chemistry.     

Cobalt-catalyzed sequential cyclization/cross-coupling reactions of 6-halo-1-hexene derivatives with Grignard reagents and their application to the synthesis of 1,3-diols

Cobalt/N-heterocyclic carbene system or cobalt/diamine combination effectively catalyzes sequential cyclization/cross-coupling reactions of 6-halo-1-hexene derivatives with trialkylsilylmethyl, 1-alkynyl, and aryl Grignard reagents. The sequential cyclization/cross-coupling reactions are applied to the synthesis of 1,3-diols starting from siloxy-tethered 6-halo-1-hexene derivatives.     

Efficient one-pot synthesis of functionalized piperidine scaffolds via ZrOCl2·8H2O catalyzed tandem reactions of aromatic aldehydes with amines and acetoacetic esters

A highly efficient diastereoselective one-pot synthesis of functionalized piperidines has been developed based on an aqua-compatible ZrOCl₂·8H₂O catalyst via tandem reactions of aromatic aldehydes, amines, and acetoacetic esters.     

A convenient method for the addition of HI to unsaturated hydrocarbons using I2 on Al2O3

Iodine reacts, under mild conditions, with hydroxyl groups on the surface of alumina to form HI which readily adds to unsaturated hydrocarbons to form alkyl and vinyl iodides.     

Cu/ZnO/Al2O3催化剂的共沉淀-蒸氨法制备及其对二氧化碳加氢制甲醇的研究

分别以碳酸铵为沉淀剂采用共沉淀-蒸氨法(CAE)和以碳酸铵(CCA)、碳酸钠(CCS)为沉淀剂采用常规共沉淀法制备了三种Cu/ZnO/Al2O3催化剂,并运用XRD,BET,TPR和N2O滴定技术对催化剂进行了表征.结果表明:采用共沉淀-蒸氨法制备的催化剂具有较小的颗粒尺寸、较大的Cu(0)比表面积;以碳酸铵为沉淀剂常...     

Facile and convenient method of deuterium gas generation using a Pd/C-catalyzed H2-D2 exchange reaction and its application to synthesis of deuterium-labeled compounds

The Pd/C-catalyzed H(2)-D(2) exchange reaction using a H(2)-D(2)O combination provided a general, efficient and environmentally friendly route for the preparation of deuterium gas (D(2)). H(2) sealed in a reaction flask was converted into nearly pure D(2), which could be used for the Pd/C-catalyzed one-pot reductive deuteration of various reducible functionalities and the chemoselective one-pot deuterogenation of olefin and acetylene. Additionally, we established the capturing method of the generated D(2) in a balloon, which was successfully applied to the Pd/C-catalyzed reductive mono-N-alkylation of a primary amine using nitrile as the alkylating reagent.