604-53-5Relevant articles and documents
Dynamics of Atropisomerization of 1,1'-Binaphtyl in Several Nematic Solvents. Rate Enhancement by a Solid Phase
Naciri, Jaouad,Spada, Gian Pierro,Gottarelli, Giovanni,Weiss, Richard G.
, p. 4352 - 4357 (1987)
The rates of atropisomerization of (S)-1,1'-binaphtyl (BN) are compared in six nematic phases and in the solid phase of p-methoxybenzylidene-p-n-butylaniline.The influence of each phase on the activation parameters for atropisomerization are correlated with the solvent molecular structures.The results in the nematic and solid phases are interpreted in terms of degree to which the solvent matrices flatten the angle between the naphtyl rings of BN.
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Smith
, (1877)
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Origin of the excellent catalytic activity of Pd loaded on ultra-stable y zeolites in Suzuki-Miyaura reactions
Okumura, Kazu,Tomiyama, Takuya,Okuda, Shizuyo,Yoshida, Hiroyuki,Niwa, Miki
, p. 156 - 166 (2010)
Suzuki-Miyaura reactions were performed over Pd loaded on (ultra-stable Y) USY zeolites prepared by steam treatment of NH4-Y. We found that the catalytic activity of Pd increased significantly with steam treatment of NH 4-Y when 6% H2 was applied before and during the reactions. For instance, a TON of 13,000,000 was obtained in the reaction between bromobenzene and phenylboronic acid in 1.5 h. Pd K-edge and Pd L 3-edge X-ray absorption fine structure analyses revealed the formation of atomic Pd with a cationic character. The catalytic activity of Pd/USY prepared under different steam-treatment conditions was in good correlation with the strong Bronsted acid sites induced by the extra-framework Al. Based on the catalytic performance data, the structure of Pd, and acidic analysis of the support, atomic Pd anchored to the strong Bronsted acid sites of the USY zeolite was proposed to be the active species.
Structures and photoluminescence of Silver(I) and Gold(I) cyclic trinuclear complexes with aryl substituted pyrazolates
Saotome, Mai,Shimizu, Daichi,Itagaki, Ayaka,Young, David James,Fujisawa, Kiyoshi
, p. 533 - 536 (2019)
The 4-aryl substituted pyrazolate ligands, L1(Ph)H and L1(Naph)H, were synthesized by SuzukiMiyaura cross-coupling and combined with metal sources to give cyclic trinuclear structures [AgL1(Ph)]3, [AuL1(Ph)] 3, [AgL1(Naph)] 3, and [AuL1(Naph)]3. The aryl group determined the crystal packing of these cyclic trinuclear complexes with the phenyl systems exhibiting stair type solid state structures and the naphthyl complexes exhibiting irregular structures with spaces occupied with some solvent molecules. These differences in solid-state structures were accompanied by differences in MN stretching frequencies and temperature dependent photoluminescence.
Deracemization of a Racemic Compound by Using Tailor-Made Additives
Engwerda, Anthonius H. J.,van Schayik, Pim,Jagtenberg, Henjo,Meekes, Hugo,Rutjes, Floris P. J. T.,Vlieg, Elias
, p. 2863 - 2867 (2018)
Viedma ripening is a process that combines abrasive grinding of a slurry of crystals with solution-phase racemization, resulting in solid-phase deracemization. One of the major disadvantages of Viedma ripening is that the desired compound needs to crystallize as a racemic conglomerate, accounting for only 5–10 % of all chiral molecules. Herein, we show that use of a chiral additive causes deracemization under conditions, in which the compound normally crystallizes as a racemic compound. Although this concerns a single example, it is envisioned that through this new approach the scope of Viedma ripening can be significantly expanded.
Suzuki homo-coupling reaction based fluorescent sensors for monosaccharides
Xu, Su-Ying,Wang, Hui-Chen,Flower, Stephen E.,Fossey, John S.,Jiang, Yun-Bao,James, Tony D.
, p. 35238 - 35241 (2014)
Palladium catalysed, aryl boronic acid homocoupling, is explored as a fluorescence sensing regime for saccharides. The catalytic formation rate of fluorescent bi-aryls, under control of a palladium catalyst, is modulated by the presence of saccharides. The nature of the aryl group, rate of biaryl formation and limits of detection are investigated.
Sterically enhanced 2-iminopyridylpalladium chlorides as recyclable ppm-palladium catalyst for Suzuki–Miyaura coupling in aqueous solution
Liang, Tongling,Lin, Wenhua,Ma, Yanping,Sun, Wen-Hua,Zhang, Liping
, (2021/10/20)
Sterically hindered 2-iminopyridine derivatives and their palladium chlorides complexes are designed and prepared, which efficiently promote the Suzuki–Miyaura coupling (SMC) reaction in aqueous solution. Besides the good to excellent yields and broad substrate scope, these catalysts can be reused for at least four new batches of the substrates. Spontaneous separation of coupling products in the aqueous reaction medium is the additional striking feature of this catalytic process. Furthermore, catalytic performance of palladium complexes bearing the azo-bridged phenyl groups was greatly influenced by the UV irradiation due to the cis/trans photoisomerization of azo unit of the catalysts. In conclusion, titled palladium complexes provide a green, sustainable, cost-effective, and convenient process to synthesize SMC products at multi-gram-scale reaction.
MeOTf-catalyzed formal [4?+?2] annulations of styrene oxides with alkynes leading to polysubstituted naphthalenes through sequential electrophilic cyclization/ring expansion
Chen, Chao,Xi, Chanjuan,Zhang, Zeyu,Zou, Song
supporting information, (2021/12/30)
MeOTf-catalyzed formal [4 + 2] annulation of styrene oxides with alkynes to afford polysubstituted naphthalenes has been realized, which undergoes sequential electrophilic cyclization/ring expansion. A range of substrates were tolerated in the formation of naphthalene derivatives with high regioselectivity in satisfactory yields. The reaction could also be carried out on gram scale.
Zirconium-redox-shuttled cross-electrophile coupling of aromatic and heteroaromatic halides
Fu, Yue,Liu, Fang-Jie,Liu, Peng,Tang, Jian-Tao,Toste, F. Dean,Wu, Ting-Feng,Ye, Baihua,Zhang, Yue-Jiao
supporting information, p. 1963 - 1974 (2021/07/07)
Transition metal-catalyzed cross-electrophile coupling (XEC) is a powerful tool for forging C(sp2)–C(sp2) bonds in biaryl molecules from abundant aromatic halides. While the synthesis of unsymmetrical biaryl compounds through multimetallic XEC is of high synthetic value, the selective XEC of two heteroaromatic halides remains elusive and challenging. Herein, we report a homogeneous XEC method, which relies on a zirconaaziridine complex as a shuttle for dual palladium-catalyzed processes. The zirconaaziridine-mediated palladium (ZAPd)-catalyzed reaction shows excellent compatibility with various functional groups and diverse heteroaromatic scaffolds. In accord with density functional theory (DFT) calculations, a redox transmetallation between the oxidative addition product and the zirconaaziridine is proposed as the crucial elementary step. Thus, cross-coupling selectivity using a single transition metal catalyst is controlled by the relative rate of oxidative addition of Pd(0) into the aromatic halide. Overall, the concept of a combined reducing and transmetallating agent offers opportunities for the development of transition metal reductive coupling catalysis.
