有机合成中的过渡金属催化剂

有机过渡金属络合物作为催化剂在有机合成中的重要性正在与日俱增。过渡金属络合物催化剂催化的有机合成反应具有反应条件温和,操作简便,选择性好,产率高,少污染等特点,在有机合成及精细化工生产中有着十分广泛的应用。     

Diastereoselective Alkylation of (Diene-Aldehyde)Fe(CO)3 Complexes with Functionalized Zinc-Copper Reagents NuCu(CN)Znl

Addition of functionalized zinc-copper reagents to the title complexes proceeds in a highly diastereoselective fashion to afford dienol complexes. The relative configurations of adducts 3d were determined by single X-ray diffraction analysis.     

Transition metal salts dependent intramolecular cyclization of a diimine

1,4-Bis(N-tosylethylamino)-2,3-diphenyl-1,4-diaza-1,3-butadiene (L¹) was separated from a condensation reaction of benzil with N-tosyl-ethylenediamine. It was shown that the intramolecular cyclization of L¹ has much dependence on the transition metal salts. The transformation of L¹ in the absence of any transition metal salts gave product 1-tosylaminoethyl-2-tosylaminomethyl-4,5-diphenyl-1H- imidazole (L²) at a temperature above 100 °C. Similar reactions assisted by Ni(CH₃COO)₂·4H₂O, MnCl₂·4H₂O, Mn(CH₃COO)₂·4H₂O, NiCl₂·6H₂O or NiSO₄·7H₂O could also give L² at a much lower temperature and a much higher yield. However, the presence of Cu(CH₃COO)₂·H₂O in a similar transformation reaction led to the formation of a bicyclic derivative 1-tosyl-5,6-diphenyl-1H-2,3-dihydroimidazo[1,2-a]imidazole (L³). But both L² and L³ were not detected when Co(CH₃COO)₂·4H₂O was used in a similar reaction and all attempts to transform L² into L³ failed.     

纳米过渡金属催化剂在有机合成中的应用进展

纳米尺度的催化剂具有高的比表面积和表面能, 其催化活性显著高于传统催化剂. 综述了近年来纳米级过渡金属催化剂在有机合成方面的应用, 并对其发展作了展望.     

Synthesis of novel mercury heterocycles

Ortho-mercurated 4-aryloxymethylcoumarins and 1-azacoumarins have been found to undergo smooth intramolecular metalation in refluxing xylene in the presence of activated neutral alumina and anhydrous potassium carbonate. This is the first report on the synthesis of heterocycles not possessing a metal heteroatom linkage.     

新型N-甲基-N-烯丙基吗啡啉季铵盐类离子液体的合成

离子液体对某些无机和有机物溶解性能好、液态温度和电化学窗口范围宽、热稳定性高、易制备,因而近年来成为国内外研究的热点,目前的离子液体大多由烷基吡啶或双烷基咪唑季铵盐阳离子与氯铝酸根、氟硼酸根、六氟磷酸根以及其它大的阴离子构成,在季铵盐类离子液体中,     

Traceless Approach for the Synthesis of 3,5-Disubstituted Thiohydantoins on Functionalized Ionic-Liquid Support

A traceless approach for the synthesis of 3,5-disubstituted thiohydantoins on a novel functionalized ionic-liquid support, 5, is described. Acylation of benzylamine functionalized ionic-liquid support with amino acids yielded ionic-liquid-supported amino acids, which reacted with isothiocyanates to afford ionic-liquid-supported thioureas. Following intramolecular cyclization cleavage from the ionic-liquid support by trifluoroacetic acid (TFA), the desired 3,5-disubstituted thiohydantoins were obtained in good yields and purities. The efficiency of this ionic-liquid-phase strategy facilitated isolation and analysis of intermediates and removal of excess reagents and by-products during the reaction process.     

Hydrozirconation: A New Transition Metal Reagent for Organic Synthesis

Hydrozirconation has recently been developed as a procedure for functionalizing alkenes, alkynes, and 1,3-dienes via organozirconium(IV) intermediates. These intermediates react with a variety of electrophilic reagents to give organic products in high yield. Mechanisms of reactions involved in these sequences are discussed.     

Synthesis of tri- and tetrasubstituted imidazoles

A reliable sequence that allows for regiospecific incorporation of four alkyl substituents on an imidazole ring has been developed. This procedure involves the addition of a substituted amino alcohol to a thioamide and subsequent oxidation with PDC. Unlike many imidazole syntheses, acid-sensitive functionality is tolerated given the mild conditions.     

Synthesis of a C8 oxygenated pyranonaphthoquinone: a useful precursor to dimeric pyranonaphthoquinones

The synthesis of a pyranonaphthoquinone bearing an oxygenated substituent at C8 is reported. The oxygen substituent at C8 provides a key functionality for use as a homocoupling precursor for the synthesis of a dimeric pyranonaphthoquinone.     

Synthesis of mono N-trifluoroethylated cyclic dipeptides

Trifluoroethylated N-termini in linear dipeptides l-TyrXOR [X = Gly, d-Ala, l-Leu, l-Phe, and l-Glu; R = H, Me, Et] exhibit sufficient nucleophilicity to give piperazine-2,5-dione ring formation through intramolecular cyclization reaction in acidic aqueous solutions. The reactions occur in high yield and with absolute configuration retention.     

Intramolecular Ene Reactions in Organic Synthesis

Thermal cyclizations of appropriate dienes, enynes and related unsaturated systems, some of them carried out on an industrial scale, demonstrate increasingly the preparative power of the intramolecular ene reaction. A variety of substituted, fused and bridged ring systems, including natural products, are thus easily accessible in a regio- and stereo-selective manner. Numerous examples are discussed systematically illustrating the possibilities, limitations, and common features of this cyclization reaction and its reverse ring-opening process.     

Synthesis and Structural Chemistry of Two Novel Transition Metal Organic Phosphonates

Two novel transition metal phosphonate compounds, [Co（H2BDPP）（phen）]n 1 （BDPP = p-O3PCH2（C6H4）CH2PO3, phen = 1,10-phenanthroline） and [Pb3（BCP）2]n 2 （BCP = OOC（C6H4）CH2PO3）, have been synthesized and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in the monoclinic system, space group C2/c with a = 21.169（4）, b = 12.001（2）, c = 7.6211（15）A, β = 98.03（3）°, V= 1917.2（6）A^3, C20H18N2O6P2Co, Mr = 505.22, Z = 8, De= 1.737 g/cm^3, p = 1.107 mm^-1, F（000） = 1020, the final R= 0.0450 and wR = 0.1306 for 2072 observed reflections （I 〉 2σ（I）. Compound 2 crystallizes in the monoclinic system, space group C2/c with a = 4.7167（9）, b = 18.753（2）, c = 22.781（3）A, β = 91.07（3）°, V= 2014.7（14）A^, C8H6O5PPb1.5, Mr = 523.88, Z = 8, Dc = 3.454 g/cm^3, p = 25.222 mm^-1, F（000） = 1856, the final R = 0.0441 and wR = 0.1906 for 2259 observed reflections （I 〉 2σ（I）. In compound 1, the 1D chain running along the c axis is bridged by four ligands （trans- HO3PCH2C6H4CH2PO3H） in four different directions to extend the structure into a three- dimensional network. In compound 2, the Pb（II） displays 4- and 5-coordination modes. There is a one-dimensional P-O-Pb band along the a axis formed by PO3 groups and Pb（II） cations. These bands are joined by μ2-O of -COO to yield two-dimensional inorganic P-O-Pb layers which are pillared by the OOCC6HaCH2PO3 ligands to form a three-dimensional network. Moreover, compound 2 displays a strong emission band attributed to the ligand-centered （LC） transition.     

Synthesis of latonduine derivatives via intramolecular Heck reaction

The synthesis of indole ring-fused benzazepinone series as latonduine derivatives has been developed via an intramolecular Heck reaction. The scope has been enlarged not only to indole moiety but also to pyrrolo and benzo[b]thiophene nuclei. Several derivatives prepared have been evaluated in vitro for their antiproliferative activities on breast cancer cell lines. Some of them showed promising cytotoxic activities.     

碘(钅翁)盐在有机合成中的应用

本文就三价有机碘鎓盐,包括二芳基、芳基全氟烷基、芳基烯基、芳基炔基和芳基烯丙基碘鎓盐以及碘叶立德在有机合成上有用的反应进行综述。这些反应包括C-,O-,N-和S-基化,全氟烷基、烯基、炔基、烯丙基和亚烷基转移反应等。     

Synthesis of Highly Substituted N-Hydroxy Piperidine via Intramolecular Reductive Cyclization of 1-Keto-5-ketoxime

Abstract

Diasteroselective synthesis of highly substituted N-hydroxypiperidine was achieved by an intramolecular reductive cyclization of monoxime (2) of the 1,5-diketone (1), generated from 2-(cyclohexylthio)-1-phenylethanone and arylaldehyde, using NaBH₃CN. The major product N-hydroxypiperidine (3) has been found to be racemate of a single diastereomer.     

聚合物支载的不对称有机合成

聚合物支载的不对称有机合成比相应的小分子合成体系有独特的优越性。本文综述了近10年来取得了较大进展的聚合物支载的不对称有机合成体系。     

Synthesis and Characterization of a Novel Phosphonate Metal Organic Framework Starting from Copper Salts

Abstract

Increased interest in the area of metal phosphonate inorganic–organic frameworks is exemplified with a high range of applications and a rich synthetic and structural chemistry of these compounds. The synthesis and potential applications of a novel metal phosphonate, namely Cu(II) phenylvinylphosphonate (PVP) is described in this paper. Syntheses were performed starting from a 1:1 molar ratio of a Cu(NO₃)₂·6H₂O or CuSO₄·5H₂O and 1-phenylvinylphosphonic acid under hydrothermal conditions at pH values ranging between 2.8 and 3.1. The influence of different counterion for the copper salt used as the Cu(II) source on the structure and crystallinity of the final product was studied. The obtained copper(II) phenylvinylphosphonate compounds were characterized by X-ray powder diffraction, FT-IR spectroscopy, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectrometry (EDAX). A possible crystal structure for the copper (II) phenylvinylphosphonate products is proposed using semiempirical approaches.