574755-28-5Relevant articles and documents
Ni-Catalyzed Borylation of Aryl Sulfoxides
Huang, Mingming,Wu, Zhu,Krebs, Johannes,Friedrich, Alexandra,Luo, Xiaoling,Westcott, Stephen A.,Radius, Udo,Marder, Todd B.
, p. 8149 - 8158 (2021/05/10)
A nickel/N-heterocyclic carbene (NHC) catalytic system has been developed for the borylation of aryl sulfoxides with B2(neop)2 (neop=neopentyl glycolato). A wide range of aryl sulfoxides with different electronic and steric properties were converted into the corresponding arylboronic esters in good yields. The regioselective borylation of unsymmetric diaryl sulfoxides was also feasible leading to borylation of the sterically less encumbered aryl substituent. Competition experiments demonstrated that an electron-deficient aryl moiety reacts preferentially. The origin of the selectivity in the Ni-catalyzed borylation of electronically biased unsymmetrical diaryl sulfoxide lies in the oxidative addition step of the catalytic cycle, as oxidative addition of methoxyphenyl 4-(trifluoromethyl)phenyl sulfoxide to the Ni(0) complex occurs selectively to give the structurally characterized complex trans-[Ni(ICy)2(4-CF3-C6H4){(SO)-4-MeO-C6H4}] 4. For complex 5, the isomer trans-[Ni(ICy)2(C6H5)(OSC6H5)] 5-I was structurally characterized in which the phenyl sulfinyl ligand is bound via the oxygen atom to nickel. In solution, the complex trans-[Ni(ICy)2(C6H5)(OSC6H5)] 5-I is in equilibrium with the S-bonded isomer trans-[Ni(ICy)2(C6H5)(SOC6H5)] 5, as shown by NMR spectroscopy. DFT calculations reveal that these isomers are separated by a mere 0.3 kJ/mol (M06/def2-TZVP-level of theory) and connected via a transition state trans-[Ni(ICy)2(C6H5)(η2-{SO}-C6H5)], which lies only 10.8 kcal/mol above 5.
Cobalt-Catalyzed Defluorosilylation of Aryl Fluorides via Grignard Reagent Formation
Cho, Hyungdo,Cho, Seung Hwan,Jang, Minjae,Jeong, Jongheon,Kim, Hyunseok,Lee, Eunsung,Lim, Soobin
supporting information, p. 7387 - 7392 (2020/10/12)
Transition-metal-catalyzed transformations of the carbon-fluorine bond not only tackle an interesting problem of challenging bond activation but also offer new synthetic strategies where the relatively inert C-F bond is converted to versatile functional groups. Herein we report a practical cobalt-catalyzed silylation of aryl fluorides that uses a cheap electrophilic silicon source with magnesium. This method is compatible with various silicon sources and can be operated under aerobic conditions. Mechanistic studies support the in situ formation of a Grignard reagent, which is captured by the electrophilic silicon source.
Light-Induced Gold-Catalyzed Hiyama Arylation: A Coupling Access to Biarylboronates
Xie, Jin,Sekine, Kohei,Witzel, Sina,Kr?mer, Petra,Rudolph, Matthias,Rominger, Frank,Hashmi, A. Stephen K.
supporting information, p. 16648 - 16653 (2018/12/04)
Organoboron compounds are versatile synthetic building blocks. We herein report a new strategy, a photochemical gold-catalyzed chemo-selective Hiyama arylation of B,Si bifunctionalized reagents with diazonium salts, which is orthogonal to common strategies and therefore a unique tool for synthesis of valuable biarylboronates. With this new methodology a wide array of diversely functionalized sp2- and sp3-hybridized biarylboronates were obtained. Notably, the synergism of gold catalysis with copper catalysis or palladium catalysis, allows for one-pot iterative C?X (heteroatom) and C?C couplings for the rapid assembly of several simple fragments to relatively complex molecules. Mechanistic studies indicated that photosensitizer-free conditions were superior to gold/Ru(bpy)3Cl2 dual catalysis.
