21167-80-6Relevant articles and documents
Green-Synthesized Nickel Nanoparticles on Reduced Graphene Oxide as an Active and Selective Catalyst for Suzuki and Glaser-Hay Coupling Reactions
Murugan, Karthik,Nainamalai, Devarajan,Kanagaraj, Pavithara,Nagappan, Saravana Ganesan,Palaniswamy, Suresh
, (2020)
A mild and benign methodology to syntheses biaryls and 1,3-diynes has been demonstrated using the nickel nanoparticles supported on reduced graphene oxide (RGO-Ni) as a heterogeneous catalyst which is prepared using green reagents. A series of substituted biaryls and 1,3-diynes has been synthesised in good to excellent yields through C-C homocoupling reaction of arylboronic acids and terminal alkynes respectively using 1,4-dioxane as a benign solvent. The present ligand-free catalytic system proceeds smoothly under mild conditions, avoids noble and stoichiometric metal reagents and tolerates sensitive functional groups. Also has a wide substrate scope and feasible with other nitrogen and sulphur containing heteroaryl boronic acids. Hot filtration test unambiguously proves the true heterogeneity of the catalyst and which support for the further reusability of the catalyst for several times without any change in the activity. The easy preparation and simple magnetic separation, stability and reusability reveal that as-prepared RGO-Ni as a versatile catalyst for the synthesis of polyaromatic compounds both in academia and industries. Highlights: Green-synthesized RGO-Ni nanocomposite used as a heterogeneous catalyst for Suzuki type (C-C) and Glaser–Hay (C ≡ C) homocoupling coupling reactions. Ligand-free catalytic system and avoids noble and stoichiometric metal reagents Short reaction time with a minimum catalyst (nickel) loading RGO-Ni nanocomposite is highly stable, reusable, and magnetically retrievable.
Copper-Catalyzed Enantioconvergent Radical Suzuki-Miyaura C(sp3)-C(sp2) Cross-Coupling
Jiang, Sheng-Peng,Dong, Xiao-Yang,Gu, Qiang-Shuai,Ye, Liu,Li, Zhong-Liang,Liu, Xin-Yuan
supporting information, p. 19652 - 19659 (2020/12/01)
A copper-catalyzed enantioconvergent Suzuki-Miyaura C(sp3)-C(sp2) cross-coupling of various racemic alkyl halides with organoboronate esters has been established in high enantioselectivity. Critical to the success is the use of a chiral cinchona alkaloid-derived N,N,P-ligand for not only enhancing the reducing capability of copper catalyst to favor a stereoablative radical pathway over a stereospecific SN2-type process but also providing an ideal chiral environment to achieve the challenging enantiocontrol over the highly reactive radical species. The reaction has a broad scope with respect to both coupling partners, covering aryl- and heteroarylboronate esters, as well as benzyl-, heterobenzyl-, and propargyl bromides and chlorides with good functional group compatibility. Thus, it provides expedient access toward a range of useful enantioenriched skeletons featuring chiral tertiary benzylic stereocenters.
Syntheses and Spectral Properties of several Branched-chain Polyphenyls containing 1,2,3-Trisubstituted Ring(s)
Ozasa, Shigeru,Fujioka, Yasuhiro,Kikutake, Jun-ichiro,Ibuki, Eiichi
, p. 1572 - 1581 (2007/10/02)
Nine polyphenyls, including six new compound, 3'-phenyl-o-quaterphenyl (3), 2,6-diphenyl-m- (4), 2,6-diphenyl-p-terphenyl (5), 2,6,5'-triphenyl-m-terphenyl (6), 2',2''-diphenyl-m-quaterphenyl (8), and 2'-(phenyl-d5)-m-terphenyl (9), were synthesized by the Ullmann coupling reaction of aryl iodide(s) or by the Karash-type coupling reaction of deuterated aryl Grignard reagent with aryl iodide catalyzed by bis(acetylacetonato)-nickel(II).Infrared studies of the polyphenyls showed that the range 730-770 cm-1, generally accepted as the position of the C-H out-of-plane bending bands of phenyl rings, should be widened slightly to 730-781 cm-1.The high frequency bands were found to be correlated closely to the sterically overcrowded structure of terminal rings.Proton magnetic resonance spectral studies indicated that the characteristic spectral features of the polyphenyls containing 1,2,3-trisubstituted ring(s) were fully consistent with their conformational aspects deduced from stereomodels.Ultraviolet spectral data suggeted that the most probable conformation of the highly crowded 3',6''-diphenyl-o-quaterphenyl (1) is one in which the interplanar angles of the pivot bonds between the 1,2,3-trisubstituted ring and three benzene rings are rather smaller than those of the less crowded 2'-phenyl-m-terphenyl (2).Keywords - Ullmann reaction; nickel-complex-catalyzed cross-coupling; quaterphenyl; deuterated quaterphenyl; quinquephenyl; sexiphenyl; polyphenyl; IR; UV; 1H-NMR
