Ene Réaction et Réaction de Substitution sur Des Hétérocycles Catalysées par les Sels de Bi(III)

Carbonylated electrophiles react with furan, thiophene, or pyrrole derivatives in the presence of catalytic amounts of bismuth triflate or chloride, leading to either electrophilic substitution or ene reaction products.     

Synthese und Kristallstrukturen der Bismutchalkogenolate Bi(SC6H5)3, Bi(SeC6H5)3 und Bi(S‐4‐CH3C6H4)3

Synthesis and Crystal Structures of Bismuth Chalcogenolato Compounds Bi(SC₆H₅)₃, Bi(SeC₆H₅)₃, and Bi(S‐4‐CH₃C₆H₄)₃ Bismuth(III) acetate reacts with thiophenol in ethyl alcohol at 80 °C to yield Bi(SC₆H₅)₃ ( 1 ). Slow cool down of the deep yellow mixture lead to the formation of orange crystals of 1 . The homotype phenylselenolato compound of bismuth Bi(SeC₆H₅)₃ ( 2 ) has been prepared by the reaction of BiX₃ (X = Cl, Br) with Se(C₆H₅)SiMe₃ in diethyl ether. In the same way as Bi(SC₆H₅)₃ ( 1 ) the reaction between bismuth(III) acetate and 4‐tolulenethiole results in red crystals of Bi(S‐4‐CH₃C₆H₄)₃ ( 3 ). In consideration of three longer Bi–E distances (intermolecular interactions, E = S; Se) the Bi(EPh)₃ molecules form via face‐linked octahedra 1‐dimensional chains in the crystal lattice, while for 3 the 1‐dimensional chain is formed by face‐linked trigonal prisma. We reported herein the synthesis and structures of Bi(SC₆H₅)₃ ( 1 ), Bi(SeC₆H₅)₃ ( 2 ), and Bi(S‐4‐CH₃C₆H₄)₃ ( 3 ).     

Direct-type catalytic three-component Mannich reaction in aqueous media

Bismuth triflate catalyzed direct-type Mannich reaction of cyclohexanone, aromatic aldehyde, and aromatic amine proceeded smoothly in water to afford the corresponding β-amino ketone with very good yield and moderate to good anti selectivity.     

Synthesis,Structure and Thermal Decomposition of the Bismuth Silyltellurolate Bi(TeSitBu2Ph)3

The compound Bi(TeSitBu₂Ph)₃ ( 1 ) was obtained from the reaction of BiCl₃ with tBu₂PhSiTeSiMe₃ in diethyl ether. The single crystal structure analysis revealed a trigonal pyramidal structure of the BiTe₃ core and weak Bi···C_(arene) contacts. Compound 1 was characterized by multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. Thermogravimetric experiments show that compound 1 decomposes with formation of Bi₂Te₃ or a mixture of elemental bismuth and Bi₄Te₃, depending on the pressure conditions.     

水热法合成Bi2S3纳米管及其生长机理

以硝酸铋[Bi(NO)3]和硫化钠(Na2S)为反应原料, 采用水热法在120 ℃下反应12 h, 制备出Bi2S3纳米管. 利用X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、选区电子衍射(SAED)和高分辨透射电镜(HRTEM)对其结构和形貌进行了表征. 结果表明, 所制备的产物是结晶良好的正交相Bi2S3纳米管, 其外径为100~500 nm, 内径为50~200 nm, 长为1~5 μm. 根据实验结果讨论了Bi2S3纳米管的生长机理. 初步研究了反应温度和矿化剂种类对产物形貌和结构的影响.     

Bismuth triflate catalyzed Claisen rearrangement of allyl naphthyl ethers

Bismuth triflate was found to be an efficient catalyst for the Claisen rearrangement of allyl naphthyl ethers. The reaction proceeds smoothly with a catalytic amount of bismuth triflate (20 mol %) to afford the corresponding ortho-allyl naphthol in moderate to good yields in most cases.     

The first bismuth(III)-catalyzed guanylation of thioureas

This work describes the first catalytic bismuth-promoted synthesis of polysubstituted guanidines in good yields through the guanylation reaction of N-benzoyl or N-phenylthioureas with primary and secondary amines, but now employing equimolar amounts of each organic reagent. Both bismuth iodine and bismuth nitrate were efficient as inorganic thiophiles at only 5 mol % in relation to substrates, being the first example of inorganic thiophiles acting in guanylation at catalytic levels.     

Bismuth-Catalyzed Amide Reduction

In this article we report that a cationic version of Akiba's Bi^III complex catalyzes the reduction of amides to amines using silane as hydride donor. The catalytic system features low catalyst loadings and mild conditions, en route to secondary and tertiary aryl- and alkylamines. The system tolerates functional groups such as alkene, ester, nitrile, furan and thiophene. Kinetic studies on the reaction mechanism result in the identification of a reaction network with an important product inhibition that is in agreement with the experimental reaction profiles.     

Stille coupling approaches for the synthesis of 8-aryl guanines

The reaction of 8-bromoguanines with aryl and hetaryl stannanes in the presence of a palladium catalyst leads to the formation of the corresponding 8-aryl(hetaryl)guanines. It was found that the addition of triphenylarsine or triphenylbismuth strongly reduces the reaction time and increases product yields.     

Microwave-enhanced bismuth triflate-catalyzed epoxide opening with aliphatic amines

In the presence of a catalytic amount of Bi(OTf)₃·4H₂O and under microwave irradiation, neat mixtures of epoxides and amines afforded smoothly the corresponding 2-amino alcohols. A wide variety of aliphatic amines were reacted with cycloalkene oxide, styrene oxide, and stilbene oxide. The reaction proceeded rapidly and afforded the 2-amino alcohols in high up to quantitative yields. All products could be obtained without aqueous work-up by simple filtration.     

Bismuth(III) Triflate: A Safe and Easily Handled Precursor for Triflic Acid: Application to the Esterification Reaction

A series of carboxylic acids were converted into their corresponding methyl esters using bismuth(III) triflate as a catalyst in methanol. Good to excellent yields were obtained for different aliphatic or aromatic starting materials. In the reaction, bismuth triflate acts as a precursor that, upon hydrolysis, liberates sufficient triflic acid to catalyze the esterification.     

Bi(OTf)3-catalyzed tandem reaction of naphthols with β,γ-unsaturated a-ketoesters.Efficient synthesis of functionalized 4H-chromenes

An efficient synthesis of functionalized 4H-chromenes by the tandem reaction of b,g-unsaturated aketoesters with 2-naphthols,1-naphthols,and 1,3-dihydroxynaphthalenes has been accomplished with high selectivity and excellent yields in the presence of a catalytic amount of bismuth triflate [Bi(OTf)3,5 mol%] under mild conditions.The functionalized 4H-chromene synthesis and our previous 2Hchromene hemiacetal synthesis could complement each other to enrich reaction diversity.     

Selective solution-phase synthesis of BiOCl, BiVO4 and δ-Bi2O3 nanocrystals in the reaction system of BiCl3-NH4VO3-NaOH

In this study, we demonstrate a straightforward solution-phase method for the selective synthesis of BiOCl, BiVO₄ and δ-Bi₂O₃ nanocrystals by simply manipulating the reaction temperature and the BiCl₃-to-NaOH mole ratio in the reaction system of BiCl₃-NH₄VO₃-NaOH. The experimental results revealed that BiOCl, as the sole product, was prepared when designating the reaction temperature ranging from room temperature to 100 °C, regardless of the BiCl₃-to-NaOH mole ratio; on the other hand, BiOCl, BiVO₄, and δ-Bi₂O₃ nanocrystals could be selectively prepared at 140-180 °C, depending on the BiCl₃-to-NaOH mole ratio in solution. Significantly, we first report on fabricating δ-Bi₂O₃ sample, the high-temperature cubic phase commonly stabilized at 730-824 °C, at the low reaction temperature of 140-180 °C under solution-phase synthetic conditions. In addition, the δ-Bi₂O₃ sample exhibits strong emission at room temperature.     

Synthesen und Kristallstrukturanalysen von [SbI3(SbMe3)(THF)]2 und [Li(THF)4]2[Bi2Cl8(THF)2]

Syntheses and Crystal Structure Analyses of [SbI₃(SbMe₃)(THF)]₂ and [Li(THF)₄]₂[Bi₂Cl₈(THF)₂] The reaction of Me₃Sb with SbI₃ in tetrahydrofuran (THF) gives [SbI₃(SbMe₃)(THF)]₂ ( 1 ). [Li(THF)₄]₂[Bi₂Cl₈(THF)₂] ( 2 ) is formed by reaction of LiCl and BiCl₃ in tetrahydrofuran. The structures of ( 1 ) and ( 2 ) have been determined by X-ray diffractometry. Both structures contain centrosymmetric dimers with the geometry of edge sharing octahedra.     

Le Triflate de Bismuth(III) Comme Catalyseur Dans la Reaction de Carbonyl-Diels-Alder

In presence of bismuth(III) triflate, a carbonylated electrophile (ethyl mesoxalate or glyoxylate) and usual diene led selectively (60-100) the hetero carbonyl-Diels-Alder reaction with the ene reaction product. Bi(OTf) 3 exhibits strong catalytic activity and reacts under mild conditions. En présence de triflate de bismuth(III) le mésoxalate et le glyoxylate d'éthyle réagissent avec des diènes usuels pour donner un mélange de carbonyl-Diels-Alder et du produit de la ène réaction. Bi(OTf) 3 présente une forte activité catalytique et réagit dans des conditions douces.     

Bismuth nitrate-catalyzed novel synthesis of pyrrole-substituted indolinones

Synthesis of indole derivatives bound to pyrroles is a challenge. In this letter, an expeditious synthesis of these types of molecules starting from isatins and 4-hydroxy proline via a bismuth nitrate-catalyzed reaction is described.     

The First Bismuth Phosphide Complex: [Li(thf)4]+[{(tBuP)3}2Bi]−

Thermally unstable crystals of the title compound—the first bismuth phosphide complex to be structurally characterized (see picture)—are obtained by the reaction of [Bi(NMe₂)₃] with [tBuPHLi] (1:3) in THF/hexane. Berry pseudorotation of the pseudo-trigonal-bipyramidal [{(tBuP)₃}₂Bi]⁻ ion is prevented for steric reasons.     

回流法制备高分散性磷酸铋光催化剂

以乙二醇为溶剂,通过加热回流法合成了高分散性的磷酸铋光催化剂,揭示了回流温度、回流时间对形貌结构与光催化性能的影响规律。研究表明六方相磷酸铋可以通过溶剂回流过程,实现从六方相到单斜相的可控相变。该高分散磷酸铋光催化剂对亚甲基蓝溶液的降解能力随回流温度和时间增加呈先增大后减小的规律变化,在130 ℃回流2 h所制备的磷酸铋光催化剂拥有最好的活性,表观动力学常数k为0.161 min^-1。通过乙二醇回流,能在磷酸铋表面引入了羟基基团,使磷酸铋在水中分散稳定性大幅提高。     

钒酸铋颜料制备实验的改进——pH优化

使用改进的实验装置研究钒酸铋颜料制备实验中p H对产物的影响。X射线衍射分析结果表明,在选定实验条件下,产物为四方相为主的四方、单斜两相混合物。p H对钒酸铋颜色有重要影响。酸性条件下颜色偏深,为土黄色;碱性条件下为亮黄色,且p H越大,颜色越淡。推荐反应p H为9,此时产物颜色呈色调较好的亮黄色。