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1.
发展高效的不对称Suzuki-Miyaura偶联反应及其合成应用   总被引:1,自引:0,他引:1  
徐广庆  赵庆  汤文军 《有机化学》2014,(10):1919-1940
为解决不对称Suzuki-Miyaura交叉偶联反应中活性和选择性问题,我们设计并发展了一系列结构刚性的手性联芳基单膦配体.在发展高活性的大位阻交叉偶联反应方面,成功地实现了邻位四取代芳基芳基之间的Suzuki-Miyaura交叉偶联,并发展了官能团化的大位阻交叉偶联,在邻位二取代芳基溴苯与二级烷基硼酸之间的大位阻芳基烷基交叉偶联中也取得进展.在发展高立体选择性的交叉偶联反应方面,我们采用手性大位阻单膦配体和底物间次级作用相结合的设计理念,利用苯并噁唑啉酮辅基和芳基间的π-π作用,成功地发展了高立体选择性的邻位酰基化芳基芳基间不对称Suzuki-Miyaura偶联;利用极性基团双(2-氧代-3-噁唑烷基)次磷酰基(BOP)辅基和芳基间的极性π作用,成功地实现了应用性强的邻位氧基取代芳基芳基间高效不对称Suzuki-Miyaura偶联.最后我们首次将高效的不对称SuzukiMiyaura偶联方法学应用于天然产物合成,完成了手性联芳基天然产物Korupensamine A和Korupensamine B的高效不对称合成,并完成天然产物Michellamine B的立体选择性全合成.  相似文献
2.
The X-ray structure of [S4N3]Cl reveals three independent molecules, which all display π-facial interactions between the Cl and the pseudo-aromatic [S4N3]+ rings to produce a structure containing “inverse sandwich” systems.  相似文献
3.
The X-ray structure of [S4N3]Cl reveals three independent molecules, which all display π-facial interactions between the Cl and the pseudo-aromatic [S4N3]+ rings to produce a structure containing “inverse sandwich” systems.  相似文献
4.
[RTeTeR] (R = dmp = 2,6-dimethoxyphenyl) (1) reacts with bromine to give [RTeTe(Br)2R] (2) and [RTeBr3] (3), and with SOCl2 to yield [RTeTe(Cl)2R] (5) and [RTeCl3] (6). The recrystallization of compound 3 in acetone produces [RTeBr2(CH2-C(O)-CH3)] (4). The hydrolysis of 2 in aqueous ammonia and methanol containing media affords the methoxy/oxo-derivative [RTe(μ-O)(OCH3)]2 (7). All the title compounds were obtained with good yields, and strong Te?O(methoxy), as well as Te?X (X = Br, Cl) secondary interactions, support the distorted octahedral configurations shown mostly in the polymeric compounds 3, 4, 5 and 6. Complexes 2 and 5 close the series of compounds with the structure [RTeTe(X)2R] (X = Cl, Br, I), started earlier with [RTeTe(I)2R].  相似文献
5.
This work presents a series of ZnII, CdII, CoII, and PbII supramolecular complexes assembled from a bent dipyridyl derivative 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and different dicarboxyl co-ligands 2-bromoterephthalic acid (H2BTA) and tetrabromoterephthalic acid (H2TBTA). All products have been prepared under similar conditions and characterized by IR, microanalysis, and TG–DTA techniques. Single-crystal X-ray diffraction indicates that these complexes display mononuclear, 1-D, and 2-D coordination motifs, and diverse higher-dimensional extended networks are further constructed via additional secondary interactions such as H-bonding and aromatic stacking. Notably, in situ hydrolysis reaction of 3-bpo is observed in the PbII complex with H2TBTA, affording another dipyridyl-type ligand N,N′-bis(3-picolinoyl)hydrazine (3-bph). These results evidently reveal the significant substituent effect of terephthalic acid in structural direction of these metallosupramolecular systems that are also regulated by the selection of metal ions.  相似文献
6.
(PhSe)2 reacts with Br2, ethylenethiourea and PhTeBr3, further with I2, ethylenethiourea and PhTeI3, to give [PhSe(etu)][PhTeBr4] (1) (Ph = phenyl; etu = ethylenethiourea) and [PhSe(etu)][PhTeI4] (2) in very good yields.The tellurium centers present a distorted octahedral configuration, achieved through dimerization involving secondary, reciprocal Te···X interactions.In both compounds the anionic dimmers are linked through X···X interactions, attaining a one-dimensional, polymeric assembly along the b axis. Cations and anions are linked through short Se···X contacts. In addition to single crystal X-ray data, multinuclear NMR results for 1 and 2 are also presented and discussed.  相似文献
7.
A series of CoII, NiII, and CuII complexes with trans-1-(2-pyridyl)-2-(4-pyridyl)ethylene (bpe) and various polycarboxyl co-ligands have been prepared under general condition and characterized by IR, elemental analysis, and TG-DTA techniques. Single-crystal X-ray diffraction indicates that these complexes display multifarious binuclear, 1-D, and 2-D coordination motifs in virtue of the bridging polycarboxyl building blocks, in which the bpe ligand uniformly adopts the unidentate coordination by using its 4-pyridyl group. Remarkably, higher-dimensional extended networks are further formed with the aid of additional secondary interactions based on bpe (such as H-bonding and ππ stacking). These results demonstrate that bpe is a reliable bifunctional tecton to construct diverse supramolecular architectures via synergistic effect of multiple intermolecular interactions.  相似文献
8.
The first Pd(II) and Pt(II) complexes incorporating diselenophosphate (dsep) ligands are presented. Treatment of M(II) (M = Pd, Pt) salts with two equivalents of the dsep ligand in CH2Cl2 yielded square-planar compounds of the type M[Se2P(OR)2]2 (M = Pd, Pt; R = Et, iPr, nPr) (1a2c). These complexes were characterized by elemental analysis, multinuclear NMR spectroscopy and X-ray diffraction (1b and 2b). The dsep ligands coordinate to the metal in an approximately isobidentate fashion and form four-membered Se–P–Se–M chelate rings. Structural elucidations indicated that minute differences exist in the M–Se bond distances and these were observed from solution 31P NMR studies, which exhibited two sets of satellites arising from one-bond coupling to 77Se nuclei. A packing diagram showed a chain-like motif which was composed of square-planar M[Se2P(OR)2]2 units and occurred via non-covalent Se⋯Se secondary interactions.  相似文献
9.
Regio- and stereoselectivities in cycloadditions of nitrones to dipolarophiles bearing an allylic oxygen, which furnishes substituted-isoxazolidine analogs of the furanose ring of nucleosides, have been investigated. Although the obtained regioselectivities are anticipated, a rationalization of the preferred formation of endo-cycloadducts necessitates the involvement of an allylic oxygen in secondary interaction. The obtained isoxazolidines display cytotoxic activities against a number of human cancer cell lines.  相似文献
10.
The crystal structure of (1-naphthyl)(4-methyl- phenyl)tellurium(IV) dibromide, the first unsymmetrical naphthyl containing diorganotellurium(IV) dibromide, shows the formation of one-dimensional supramolecular arrays where Te···Br secondary bonds link two parallel rows of molecules in a gear-teethed fashion. The weaker C–H···Br and C–H···π hydrogen bonds play important role in the formation of three-dimensional crystal lattice by cross linking these supramolecular motifs.  相似文献
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