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61.
Reaction of 2 with bis(tributyltin) in the presence of 3 mol % Pd2(dba)3, 6 mol % XPhos, and 30 equiv of LiBr in wet and air bubbled THF at reflux for 8 h afforded the desired products 3 in 73–74% yields. The cross-coupling reaction of 3a with aryl iodides in the presence of 10 mol % Pd(PPh3)4 and 10 mol % CuI afforded the coupled products 4a–p in 47–90% yields. The coupling reaction of 3b with various alkynyl bromides having aryl-, alkyl, or trialkylsilyl group also afforded the corresponding 1,3-enynes 5a–g in 61–77% yields. 相似文献
62.
63.
以1,1′-二羟基-5,5′-联四唑(H_2BTO)为配体,镧系金属离子作为金属中心,采用溶剂热法制备了5种金属配合物:[La_2(BTO)_3(H_2O)_8]·2H_2O (1)、[Ce_2(BTO)_3(H_2O)_8]·2H_2O (2)、[Pr_2(BTO)_3(H_2O)_8]·2H_2O (3)、[Sm_2(BTO)_3(H_2O)_8]·2H_2O (4)和[Nd_2(BTO)_3(DMF)_4]·6H_2O (5)。通过单晶X射线衍射和元素分析对5种配合物的结构进行了表征。结果表明,5种配合物均属于单斜晶系,P2_1/n空间群。利用差示扫描量热法研究了配合物1~4的热稳定性,采用Kissinger法和Ozawa法分别计算了其热分解动力学参数。 相似文献
64.
65.
A new porous Cd(Ⅱ) coordination compound, namely, [Cd(bpdc)(L)2]·3H2O(1, L = 11-fluoro-dipyrido[3,2-a:2,3-c]phenazine and bpdc = 1,1-biphenyl-2,2-dicarboxylate) was synthesized under hydrothermal conditions, and characterized by single-crystal X-ray diffraction. It crystallizes in tetragonal, space group P4122 with a = 9.8486(4), b = 9.8486(4), c = 45.925(4)A, V = 4454.5(5) 3, Z = 4, C50H29 Cd F2N8O7, Mr = 1004.21, Dc = 1.497 g/cm3, F(000) = 2028, μ(Mo Ka) = 0.562 mm-1, R = 0.0566 and w R = 0.1585. Each Cd(Ⅱ) atom is coordinated by one bpdc anion and two L ligands to give a discrete molecule. Neighboring discrete molecules are stacked by π-π interactions among L ligands, resulting in an interesting 1D supramolecular chain. Moreover, the 1D supramolecular chains are packed with each other to give a porous structure, in which an infinite channel is filled with water molecules. In addition, the thermal behavior and luminescent property of 1 have also been studied. 相似文献
66.
The molecule rac-1,1'-binaphthalene-2,2'-diol (rac-1,1'-bi-2-naphthol, rac-BINOL) shows a propensity for supramolecular, charge-assisted O–H ··· O– hydrogen-bonded strand formation when crystallized with its deprotonated form BINOLAT2– and Cu2+ in conc. ammonia. The naphthyl-paneled cavities in the {(rac-BINOLAT2–)(rac-BINOL)2} strands host the [Cu(NH3)5]2+-guest cation through second-sphere N–H ··· O hydrogen bonding in the structure of [Cu(NH3)5]2+(rac-BINOLAT2–)(rac-BINOL)2. Decreasing the copper(II) and ammonia concentrations in the crystallization leads to {(rac-BINOLAT2–)(rac-BINOL)} strands, in which rac-BINOLAT2– coordinates to two copper(II) atoms in the structure of [Cu(NH3)2(μ-rac-BINOLAT2–-κ2O,O':κO)]2(rac-BINOL)2. In the {Cu2+(NH3)2} moiety two BINOLAT-oxide atoms act as bridging ligands. Both copper structures could be obtained by using the racemic rac-BINOL or the enantiomeric R- or S-BINOL, through an in-situ racemization of the latter. 相似文献
67.
《中国化学快报》2020,31(7):1911-1913
An efficient protocol for the synthesis of asymmetric 1,3-diketones was reported through diacylation of 1,1-diborylalkanes using two different acyl sources. In this transformation, an enolate boron species was initially formed by introducing an acyl group, then it was trapped by another acyl group to form 1,3-diketone. This method not only provided the gateway to obtain a series of 1,3-diketones, but also afforded an operationally simple and efficient access to pyrazoles and isoxazoles. 相似文献
68.
Joseph M. Zanghi Simon J. Meek 《Angewandte Chemie (International ed. in English)》2020,59(22):8451-8455
A catalytic diastereo‐ and enantioselective method for the preparation of complex tertiary homoallylic alcohols containing a vicinal quaternary carbon stereogenic center and a versatile alkenylboronic ester is disclosed. Transformations are promoted by 5 mol % of a readily available copper catalyst bearing a bulky monodentate phosphoramidite ligand, which is essential for attaining both high dr and er. Reactions proceed with a wide variety of ketones and allylic 1,1‐diboronate reagents, which enables the efficient preparation of diverse array of molecular scaffolds. 相似文献
69.
Alessandro Bismuto Gary S. Nichol Fernanda Duarte Michael J. Cowley Stephen P. Thomas 《Angewandte Chemie (International ed. in English)》2020,59(31):12731-12735
The reaction of a Lewis acidic borane with an alkyne is a key step in a diverse range of main group transformations. Alkyne 1,1‐carboboration, the Wrackmeyer reaction, is an archetypal transformation of this kind. 1,1‐Carboboration has been proposed to proceed through a zwitterionic intermediate. We report the isolation and spectroscopic, structural and computational characterization of the zwitterionic intermediates generated by reaction of B(C6F5)3 with alkynes. The stepwise reactivity of the zwitterion provides new mechanistic insight for 1,1‐carboboration and wider B(C6F5)3 catalysis. Making use of intramolecular stabilization by a ferrocene substituent, we have characterized the zwitterionic intermediate in the solid state and diverted reactivity towards alkyne cyclotrimerization. 相似文献
70.
Electron impact mass spectral fragmentation of certain esters and amides derived from 4-hydroxy-2H-1,2-benzothiazine-3-carboxylic acid 1,1-dioxide is described. Common ions to both series may be observed, as well as others allowing them to be differentiated. The method is promissory for identification and analysis of these compounds. 相似文献