13863-27-9Relevant academic research and scientific papers
Structural requirements for palladium catalyst transfer on a carbon-carbon double bond
Nojima, Masataka,Ohta, Yoshihiro,Yokozawa, Tsutomu
, p. 5682 - 5685 (2015)
Intramolecular transfer of tBu3PPd(0) on a carbon-carbon double bond (C=C) was investigated by using Suzuki-Miyaura coupling reaction of dibromostilbenes with aryl boronic acid or boronic acid esters in the presence of various additi
A Novel Synthetic Approach to Biphenyls
Ho, Tong-Ing,Shu, Cheng-Shein,Yeh, Ming-Kuo,Chen, Fa-Ching
, p. 795 - 797 (1987)
Two novel biphenyls, 2,2'-bis(1-hydroxyethyl)-3,3',5,5'-tetramethylbiphenyl (7) and 2,2'-bis(1-hydroxyethyl)-4,4'6,6'-tetramethylbiphenyl (13) were synthesized through Wittig reaction, photochemical oxidative cyclization, and ozonolysis, using xylene and mesitylene as starting materials.The novel approach is applicable to both symmetrical and unsymmetrical biphenyls.
Catalytic Syn-Selective Nitroaldol Approach to Amphenicol Antibiotics: Evolution of a Unified Asymmetric Synthesis of (-)-Chloramphenicol, (-)-Azidamphenicol, (+)-Thiamphenicol, and (+)-Florfenicol
Chen, Fener,Cheng, Dang,Huang, Huashan,Jiang, Meifen,Liu, Minjie,Qu, Hongmin,Xia, Yingqi,Xiong, Tong,Zhang, Yan
supporting information, p. 11557 - 11570 (2021/09/02)
A unified strategy for an efficient and high diastereo- and enantioselective synthesis of (-)-chloramphenicol, (-)-azidamphenicol, (+)-thiamphenicol, and (+)-florfenicol based on a key catalytic syn-selective Henry reaction is reported. The stereochemistry of the ligand-enabled copper(II)-catalyzed aryl aldehyde Henry reaction of nitroethanol was first explored to forge a challenging syn-2-amino-1,3-diol structure unit with vicinal stereocenters with excellent stereocontrol. Multistep continuous flow manipulations were carried out to achieve the efficient asymmetric synthesis of this family of amphenicol antibiotics.
AIR-STABLE NI(0)-OLEFIN COMPLEXES AND THEIR USE AS CATALYSTS OR PRECATALYSTS
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Page/Page column 13-15, (2021/02/05)
The present invention relates to air stable, binary Ni(0)-olefin complexes and their use in organic synthesis.
Ni(4?Tbustb)3: A robust 16-electron Ni(0) olefin complex for catalysis
Nattmann, Lukas,Cornella, Josep
supporting information, p. 3295 - 3300 (2020/10/12)
Sixteen-electron Ni(0) complexes bearing trans-stilbene derivative ligands have been shown to display a high degree of stability toward oxidation in the solid state. A structural analysis of a unique family of tris Ni(0) stilbene complexes revealed a remarkable effect of the steric hindrance of the substituents at the para position of the stilbene unit to temperature, oxidation, and degradation in solution. From these analyses, Ni(4?tBustb)3 arose as a long-term air-, bench-. and temperature-stable Ni(0) complex. Importantly, Ni(4?tBustb)3 presents faster kinetic profiles and a broader scope as a Ni(0) source, thus outperforming the previously described Ni(4?CF3stb)3 in a variety of relevant Ni-catalyzed transformations.
Acetylene as a Dicarbene Equivalent for Gold(I) Catalysis: Total Synthesis of Waitziacuminone in One Step
Armengol-Relats, Helena,Echavarren, Antonio M.,Escofet, Imma,Korber, J. Nepomuk,Scharnagel, Dagmar,de Orbe, M. Elena
supporting information, p. 4888 - 4891 (2020/02/11)
The gold(I)-catalyzed reaction of acetylene gas with alkenes leads to (Z,Z)-1,4-disubstituted 1,3-butadienes and biscyclopropanes depending on the donor ligand on gold(I). Acetylene was generated in situ from calcium carbide and water in a user-friendly p
Ethylaluminum as an ethylene source for the Mizoroki-Heck-type reaction. Rhodium-catalyzed preparation of stilbene derivatives
Tanaka, Shota,Itami, Kazuki,Sunahara, Kazuhiro,Tatsuta, Go,Mori, Atsunori
supporting information, p. 1949 - 1952 (2015/02/05)
Treatment of an organoaluminum reagent bearing aryl and ethyl groups furnishes 1,2-diarylethene derivatives in good to excellent yields by the catalysis of a rhodium complex, in which the ethyl group of the aluminum reagent serves as an ethylene source in the product formation.
An alkene-promoted borane-catalyzed highly stereoselective hydrogenation of alkynes to give Z- And E-alkenes
Liu, Yongbing,Hu, Lianrui,Chen, Hui,Du, Haifeng
supporting information, p. 3495 - 3501 (2015/03/04)
The stereoselective hydrogenation of alkynes to alkenes is an extremely useful transformation in synthetic chemistry. Despite numerous reports for the synthesis of Zalkenes, the hydrogenation of alkynes to give E-alkenes is still not well resolved. In particular, selective preparation of both Z- and E-alkenes by the same catalytic hydrogenation system using molecular H2 has rarely been reported. In this paper, a novel strategy of using simple alkenes as promoters for the HB(C6F5)2-catalyzed metal-free hydrogenation of alkynes was adopted. Significantly, both Z - and E-alkenes can be furnished by hydrogenation with molecular H2 in high yields with excellent stereoselectivities. Further experimental and theoretical mechanistic studies suggest that interactions between H and F atoms of the alkene promoter, borane intermediate, and H2 play an essential role in promoting the hydrogenolysis reaction.
Catalytic enantioselective allyl- and crotylboration of aldehydes using chiral diol·SnCl4 complexes. Optimization, substrate scope and mechanistic investigations
Rauniyar, Vivek,Zhai, Huimin,Hall, Dennis G.
supporting information; experimental part, p. 8481 - 8490 (2009/02/02)
We report a novel class of C2-symmetric chiral diols derived from the hydrobenzoin skeleton. The combination of these diols with SnCl 4 under Yamamoto's concept of Lewis acid assisted Bronsted acidity (LBA catalysis) leads to high levels of asymmetric induction in the allylboration of aldehydes by commercially available allylboronic acid pinacol ester 1a. The corresponding homoallylic alcohol products of synthetically useful aliphatic aldehydes are obtained in excellent yields with up to 98:2 er. This combined acid manifold is also efficient in catalyzing the diastereo- and enantioselective crotylboration of aldehydes, thus providing the propionate units in >95:5 dr and up to 98:2 er. The X-ray crystal structure of the optimal diol·SnCl4 complex, Vivol (4m)·SnCl 4, unambiguously shows the Bronsted acidic character of this LBA catalyst and its highly dissymmetrical environment. Further controls have ruled out a possible boron transesterification mechanism with the chiral diol and point to LBA catalyst-derived activation of the pinacol allylic boronates 1. Due to slow dissociation of the diol·SnCl4 complex, a small excess of diol is required in order to suppress a competing racemic cycle catalyzed by free SnCl4.
Catalytic enantioselective and catalyst-controlled diastereofacial- selective additions of allyl- and crotylboronates to aldehydes using chiral Bronsted acids
Rauniyar, Vivek,Hall, Dennis G.
, p. 2426 - 2428 (2007/10/03)
(Chemical Equation Presented) Towards the ideal: A chiral diol-SnCl 4 complex is applied to the allylboration of aldehydes (see scheme). This approach highlights the use of chiral Bronsted acid catalysis in the development of an ideal method for the allylation of aldehydes which would display high diastereo- and enantioselectivity, wide substrate scope, and high practicality (ease of use, low cost, and low environmental impact).
