13021-19-7Relevant academic research and scientific papers
Single and double Suzuki-Miyaura couplings with symmetric dihalobenzenes
Sinclair, David J.,Sherburn, Michael S.
, p. 3730 - 3733 (2005)
(Chemical Equation Presented) m- or p-diiodobenzene undergoes selective double coupling reactions with arylboronic acids and esters. Selectivity for double coupling over single coupling is remarkably strong: even with a diiodobenzene:monoboronic acid ratio of 10:1, the products of double coupling are formed in good yields. Steric hindrance and electronic influences of the boronic acid or ester, and reaction conditions do not appear to impact significantly upon the outcome of the reaction. In contrast, m- and p-dibromobenzenes undergo single couplings with aryl boronic acids with high selectivity.
Studies on the synthesis, characterisation and reactivity of aromatic diboronic acids
Todd, Matthew H.,Balasubramanian, Shankar,Abell, Chris
, p. 6781 - 6784 (1997)
The synthesis and characterisation of 1,3- and 1,4-phenyl diboronic acids are described, and the palladium-catalysed couplings between 1,4-phenyl diboronic acid and a number of aryl iodides is reported.
Efficient synthesis of substituted terphenyls by Suzuki coupling reaction
Chaumeil, He?le?ne,Le Drian, Claude,Defoin, Albert
, p. 757 - 760 (2002)
The Suzuki cross-coupling reactions of phenyl-1,4-diboronic acid bis-pinacol ester with a range of aryl halides are reported. The reaction proceeded smoothly, even with sterically hindered aryl halides, to give symmetrical terphenyls often quantitatively.
Palladium (II)–Salan Complexes as Catalysts for Suzuki–Miyaura C–C Cross-Coupling in Water and Air. Effect of the Various Bridging Units within the Diamine Moieties on the Catalytic Performance
Bunda, Szilvia,Joó, Ferenc,Kathó, ágnes,Udvardy, Antal,Voronova, Krisztina
supporting information, (2020/09/18)
Water-soluble salan ligands were synthesized by hydrogenation and subsequent sulfonation of salens (N,N’-bis(slicylidene)ethylenediamine and analogues) with various bridging units (linkers) connecting the nitrogen atoms. Pd (II) complexes were obtained in reactions of sulfosalans and [PdCl4]2?. Characterization of the ligands and complexes included extensive X-ray diffraction studies, too. The Pd (II) complexes proved highly active catalysts of the Suzuki–Miyaura reaction of aryl halides and arylboronic acid derivatives at 80 ?C in water and air. A comparative study of the Pd (II)–sulfosalan catalysts showed that the catalytic activity largely increased with increasing linker length and with increasing steric congestion around the N donor atoms of the ligands; the highest specific activity was 40,000 (mol substrate) (mol catalyst × h)?1. The substrate scope was explored with the use of the two most active catalysts, containing 1,4-butylene and 1,2-diphenylethylene linkers, respectively.
Small Phosphine Ligands Enable Selective Oxidative Addition of Ar-O over Ar-Cl Bonds at Nickel(0)
Entz, Emily D.,Hooker, Leidy V.,Neufeldt, Sharon R.,Russell, John E. A.
, p. 15454 - 15463 (2020/10/18)
Current methods for Suzuki-Miyaura couplings of nontriflate phenol derivatives are limited by their intolerance of halides including aryl chlorides. This is because Ni(0) and Pd(0) often undergo oxidative addition of organohalides at a similar or faster rate than most Ar-O bonds. DFT and stoichiometric oxidative addition studies demonstrate that small phosphines, in particular PMe3, are unique in promoting preferential reaction of Ni(0) with aryl tosylates and other C-O bonds in the presence of aryl chlorides. This selectivity was exploited in the first Ni-catalyzed C-O-selective Suzuki-Miyaura coupling of chlorinated phenol derivatives where the oxygen-containing leaving group is not a fluorinated sulfonate such as triflate. Computational studies suggest that the origin of divergent selectivity between PMe3 and other phosphines differs from prior examples of ligand-controlled chemodivergent cross-couplings. PMe3 effects selective reaction at tosylate due to both electronic and steric factors. A close interaction between nickel and a sulfonyl oxygen of tosylate during oxidative addition is critical to the observed selectivity.
Unified Protocol for Fe-Based Catalyzed Biaryl Cross-Couplings between Various Aryl Electrophiles and Aryl Grignard Reagents
Wang, Lei,Wei, Yi-Ming,Zhao, Yan,Duan, Xin-Fang
, p. 5176 - 5186 (2019/05/10)
The combination of commonly used FeCl3/SIPr with Ti(OEt)4/PhOM enabled a highly general iron-based catalyst system, which could efficiently catalyze the biaryl coupling reaction between various electrophiles (I, Br, Cl, OTs, OCONMe2, OSO2NMe2) and common or functionalized aryl Grignard reagents with high functional group tolerance. Selective couplings of aryl iodides and bromides over the corresponding oxygen-based electrophiles have been achieved, and thus a terphenyl acid intermediate for anidulafungin was conveniently synthesized via an orthogonal coupling strategy.
Aryl/heteroaryl pentafluorobenzenesulfonates (ArOPFBs): New electrophilic coupling partners for room temperature Suzuki-Miyaura cross-coupling reactions
Joseph, Jayan T.,Sajith, Ayyiliath M.,Ningegowda, Revanna C.,Nagaraj, Archana,Rangappa,Shashikanth, Sheena
, p. 5106 - 5111 (2015/08/06)
The first cross-coupling reaction between aryl/heteroaryl pentafluorobenzenesulfonates and aryl/heteroaryl boronic acids under mild conditions is described. The successful synthesis of highly ortho substituted biaryls and high chemoselectivity of these bench stable intermediates over tosylates, triflates, mesylates, and chlorides increases its scope as a valuable cross-coupling partner. The generality of this protocol was further extended to other boron containing nucleophiles (boronates, trifluoroborates) and alkyl boronic acids.
Synthesis and Properties of High-Temperature Mesomorphic Polysiloxane Solvents: Biphenyl- and Terphenyl-Based Nematic Systems
Apfel, M. A.,Finkelmann, H.,Janini, G. M.,Laub, R. J.,Luehmann, B.-H.,et al.
, p. 651 - 658 (2007/10/02)
The synthesis and characterization of a variety of mesomorphic (liquid-crystalline) side-chain polysiloxane (MEPSIL) solvents, said to be useful as gas chromatographic stationary phases, are described and discussed.The synthetic scheme is based upon the hydrosilation reaction that occurs when 4-(allyloxy)benzoyl esters are contacted with poly(methylsiloxane) in the presence of a dicyclopentadienylplatinum(II) catalyst, while product characterization is carried out by IR, NMR, GC, DSC, elemental analysis, and direct-observation hot-stage light-polarized microscopy.Selectivity of the MEPSIL phases is shown to differ very substantially from those exhibited by all other common GC solvents.The MEPSIL found overall to be the best suited as a GC stationary liquid exhibits a melting point of 139 deg C (k -> n) and a nematic/isotropic (n -> i) transition temperature of 319 deg C, while the practical operating limits of the material span 150 to in excess of 300 deg C.
