铑/双膦配体催化均相内烯烃氢甲酰化反应的研究进展

烯烃氢甲酰化反应是工业上合成醛的重要方法.由于双膦配体良好的配位能力,形成的铑配合物有很好的催化活性,在内烯烃氢甲酰化反应中,可以有效地提高直链醛选择性.本文系统地综述了近年来双膦配体铑配合物催化均相内烯烃氢甲酰化反应的研究进展,讨论了双膦配体结构对催化剂活性和生成直链醛选择性的影响.     

新型配体1—苯基二苯并膦在丙烯氢甲酰化均相反应中的应用研究

将 1-苯基二苯并膦 (PDBP)作为膦配体用于丙烯氢甲酰化反应中 ,系统研究了反应温度、压力、铑浓度、搅拌速率对产物丁醛收率的影响 .在铑浓度为 4.0× 10 - 6 、 P/ Rh比为 15 0、温度 10 0℃、反应压力 2 .0 MPa的条件下 ,丙烯转化率可达 90 % ,催化活性为 2 6 0 9g丁醛 / (g Rh· h) ,正丁醛和异丁醛的比达 9.5 .在相同的条件下与工业上广泛采用的以三苯基膦为配体的铑催化剂相比较 ,以 PDBP为配体的铑催化剂的活性和选择性分别是它的 1.44倍和 1.90倍 .证明了 PDBP是一个很有发展前景的羰基合成的膦配体     

二羰基水杨醛肟铑配合物催化的苯乙烯常压氢甲酰化反应

用Rh~2(CO)~4Cl~2与水杨醛肟的钠盐反应合成了二羰基水杨醛肟铑配合物Rh(sox)(CO~2)(1)。在常压下研究了该配合物与膦或亚磷酸酯组成的体系对苯乙烯氢甲酰化反应的催化性能, 此体系对烯烃没有催化加氢作用, 产物醛的化学选择性均为100%。考察了膦的结构与用量对催化活性和选择性的影响, 双膦作配体时活性和选择性都高于单膦, 其中Rh(sox)(CO)~2-Ph~2P(CH~2)~3PPh~2体系的最高初活性(TON)可达1.60min^-^1, 2-苯基丙醛的选择性在90%以上。对反应的活性物种作了初步讨论。     

新型膦配体PDBPDS在氢甲酰化反应中催化剂配体性能的研究

用量子化学 AMI方法优化了 1 -苯基二苯并膦二磺化产物 ( PDBPDS)和三磺化三苯基膦 ( TPPTS)的几何构型 .比较两种化合物的空间结构和电子结构发现 ,在氢甲酰化铑膦催化反应体系中 ,PDBPDS的配体性能优于 TPPTS.首次研究了以 PDBPDS为配体的铑膦催化剂对丙烯氢甲酰化反应的催化性能 ,考察了反应温度、压力、膦铑物质的量比和搅拌速度对催化活性和选择性的影响 .结果表明 ,在 2 .0 MPa,1 0 0℃ ,膦铑物质的量比为 35 ,搅拌速度为 5 0 0 r/min及 V( H2 ) /V( CO) =1 /1的条件下 ,催化活性可达到 2 80 0 g(丁醛 ) /[g(铑 )·h],正异构产物物质的量比为 1 2 .3,在相同条件下与传统的三磺化三苯基膦 ( TPPTS)为配体的铑膦催化剂相比 ,催化活性和选择性提高了 2倍 .反应结束后 ,有机相和水相分离简单 ,有机相铑浓度仅为3.6× 1 0 - 8mol/L,有效地解决了铑流失问题 ,表明 PDBPDS是极具开发前景的新型水溶性配体     

室温离子液体中水溶性铑膦配合物催化1-己烯氢甲酰化反应的研究

研究了水溶性膦配体铑配合物在若干离子液体中的1-己烯氢甲酰化反应性能．通过改变离子液体的阴阳离子结构，可使水溶性TPPTS-铑配合物在离子液体中表现出较高的卜己烯氢甲酰化反应活性和选择性；在[BMI]BF4离子液体中加入适量的水，可提高TPPTS-铑配合物的催化活性；在[BMI]BF4离子液体中，水／有机两亲性膦配体与铑形成的配合物，反应后催化剂与产物自动分层，实现催化剂的循环使用．本文结果表明，水溶性膦配体铑配合物的催化活性与其在离子液体中的溶解度密切相关．     

铑催化的烯烃不对称氢甲酰化反应研究进展

烯烃的氢甲酰化反应是工业上最重要的均相催化反应之一,而通过烯烃的不对称氢甲酰化反应合成光学活性醛,对于药物、农药、香料和天然产物合成方面具有重要的意义.近年来,由于铑与膦配体形成的络合物在催化烯烃的不对称氢甲酰化反应中具有反应活性高、选择性好等优点而引起广泛关注.通过调控铑络合物中手性膦配体的电子与立体化学环境,已经成为实现不对称氢甲酰化反应高活性和高选择性最主要的方法.主要介绍了近期在铑催化的不对称氢甲酰化反应研究方面取得的进展,重点介绍几类代表性的手性膦配体在此类反应中的应用.     

新型配体三 (3,4-二甲氧基苯基) 膦的合成及其 Rh 配合物在 1-十二烯氢甲酰化反应中的催化性能

 将合成的三 (3,4-二甲氧基苯基) 膦 (TDMOPP) 用作 Rh 催化剂配体, 并用于 1-十二烯氢甲酰化反应, 考察了膦/铑比和反应温度对 Rh-TDMOPP 催化剂活性和选择性的影响. 结果表明, 在膦/铑比与反应温度较低时, Rh-TDMOPP 活性是 Rh-三苯基膦催化剂的 3 倍.     

锚链固定的多相化铑膦配合物氢甲酰化反应催化剂的制备及其催化性能

以溶胶-凝胶与锚链固定相结合的方法制备了新型多相化羰基铑膦配合物催化剂.利用FT-IR,XPS和ICP对催化剂进行了表征.考察了该催化剂对1-己烯氢甲酰化反应的催化性能,得到较佳的反应条件,即反应温度100℃、反应时间12h、催化剂用量为0.3382g(相当于金属铑含量为4.4×10-5mol)、反应压力5.0MPa.此时1-己烯的转化率为98.5%、醛的选择性92.4%、n/i比1.43.该催化剂循环使用7次仍具有较高的催化活性和选择性,表明该催化剂具有好的循环使用性能.XPS、ICP分析证明铑的部分流失主要是由于氢甲酰化反条件下CO取代膦配体所致.     

新型表面活性膦在长链烯烃氢甲酰化反应中的助催化作用

 考察了新型表面活性膦配体DPPTS(对-十二烷基苯基二苯基膦的磺酸钠盐)和OPPTS(对-辛基苯基二苯基膦的磺酸钠盐)在铑络合物催化的水/有机两相长链烯烃氢甲酰化反应中的助催化作用. 在催化烯烃氢甲酰化反应时,观察到烯烃与膦配体之间有一定的链长匹配效应; 含DPPTS的催化剂体系在低膦/铑比条件下表现出比含表面活性剂十六烷基三甲基溴化铵和水溶性配体三苯基膦三磺酸钠的催化剂体系高得多的催化活性,而且铑流失到有机相极少,仅为加入总铑量的0.8%. 这种亲水基团和磷原子处于碳链同一端的表面活性膦配体比文献报道的亲水基团和磷原子分别处于碳链两端的表面活性膦配体具有更好的助催化活性.     

双膦配体修饰铑催化乙酸乙烯酯氢甲酰化反应(英文)

研究了双膦配体对铑催化的乙酸乙烯酯氢甲酰化反应的促进作用,结果表明,在优化反应条件下,以双膦化合物2,2’-二(二苯膦甲基)-1,1’-联苯(BISBI)为配体时,铑催化乙酸乙烯酯氢甲酰化反应的TOF(转化频率)值达到4000h1,生成2-乙酰氧基丙醛的选择性99%.当在较温和的条件下Rh/BISBI催化乙酸乙烯酯氢甲酰化反应较长时间时TON(转化数)值达到9200,成醛率超过90%,2-乙酰氧基丙醛选择性仍保持99%.     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.