479411-93-3Relevant articles and documents
Direct C?H Borylation of Arenes Catalyzed by Saturated Hydride-Boryl-Iridium-POP Complexes: Kinetic Analysis of the Elemental Steps
Esteruelas, Miguel A.,Martínez, Antonio,Oliván, Montserrat,O?ate, Enrique
supporting information, p. 12632 - 12644 (2020/09/09)
The saturated trihydride IrH3{κ3-P,O,P-[xant(PiPr2)2]} (1; xant(PiPr2)2=9,9-dimethyl-4,5-bis(diisopropylphosphino)xanthene) activates the B?H bond of two molecules of pinacolborane (HBpin) to give H2, the hydride-boryl derivatives IrH2(Bpin){κ3-P,O,P-[xant(PiPr2)2]} (2) and IrH(Bpin)2{κ3-P,O,P-[xant(PiPr2)2]} (3) in a sequential manner. Complex 3 activates a C?H bond of two molecules of benzene to form PhBpin and regenerates 2 and 1, also in a sequential manner. Thus, complexes 1, 2, and 3 define two cycles for the catalytic direct C?H borylation of arenes with HBpin, which have dihydride 2 as a common intermediate. C?H bond activation of the arenes is the rate-determining step of both cycles, as the C?H oxidative addition to 3 is faster than to 2. The results from a kinetic study of the reactions of 1 and 2 with HBpin support a cooperative function of the hydride ligands in the B?H bond activation. The addition of the boron atom of the borane to a hydride facilitates the coordination of the B?H bond through the formation of κ1- and κ2-dihydrideborate intermediates.
Immobilization of Ir(I) complex on covalent triazine frameworks for C–H borylation reactions: A combined experimental and computational study
Tahir, Norini,Muniz-Miranda, Francesco,Everaert, Jonas,Tack, Pieter,Heugebaert, Thomas,Leus, Karen,Vincze, Laszlo,Stevens, Christian V.,Van Speybroeck, Veronique,Van Der Voort, Pascal
, p. 135 - 143 (2019/02/12)
Metal-modified covalent triazine frameworks (CTFs) have attracted considerable attention in heterogeneous catalysis due to their strong nitrogen-metal interactions exhibiting superior activity, stability and hence recyclability. Herein, we report on a post-metalation of a bipyridine-based CTFs with an Ir(I) complex for C–H borylation of aromatic compounds. Physical characterization of the Ir(I)-based bipyCTF catalyst in combination with density functional theory (DFT) calculations exhibit a high stabilization energy of the Ir-bipy moiety in the frameworks in the presence of B2Pin2. By using B2Pin2 as a boron source, Ir(I)@bipyCTF efficiently catalyzed the C–H borylation of various aromatic compounds with excellent activity and good recyclability. In addition, XAS analysis of the Ir(I)@bipyCTF gave clear evidence for the coordination environment of the Ir.
meta-Nitration of Arenes Bearing ortho/para Directing Group(s) Using C?H Borylation
Li, Xuejing,Deng, Xingwang,Coyne, Anthony G.,Srinivasan, Rajavel
supporting information, p. 8018 - 8023 (2019/05/29)
Herein, we report the meta-nitration of arenes bearing ortho/para directing group(s) using the iridium-catalyzed C?H borylation reaction followed by a newly developed copper(II)-catalyzed transformation of the crude aryl pinacol boronate esters into the corresponding nitroarenes in a one-pot fashion. This protocol allows the synthesis of meta-nitrated arenes that are tedious to prepare or require multistep synthesis using the existing methods. The reaction tolerates a wide array of ortho/para-directing groups, such as ?F, ?Cl, ?Br, ?CH3, ?Et, ?iPr ?OCH3, and ?OCF3. It also provides regioselective access to the nitro derivatives of π-electron-deficient heterocycles, such as pyridine and quinoline derivatives. The application of this method is demonstrated in the late-stage modification of complex molecules and also in the gram-scale preparation of an intermediate en route to the FDA-approved drug Nilotinib. Finally, we have shown that the nitro product obtained by this strategy can also be directly converted to the aniline or hindered amine through Baran's amination protocol.
