129636-11-9Relevant academic research and scientific papers
Aluminabenzene-Rh and -Ir Complexes: Synthesis, Structure, and Application toward Catalytic C-H Borylation
Nakamura, Taichi,Suzuki, Katsunori,Yamashita, Makoto
, p. 17763 - 17766 (2017)
Aluminabenzene-rhodium and -iridium complexes were synthesized, in which the aluminum atom played as a proximal Lewis acidic site. Based on their structural analysis, aluminabenzene ligand could coordinate to Rh and Ir as a η5-pentadienyl ligand. The Lewis acidic character of aluminum atom in aluminabenzene ligand was confirmed by treatment with 4-dimethylaminopyridine to form the corresponding Lewis acid-base complexes. In addition, the α-selective C-H borylation of triethylamine with the aluminabenzene-ligated iridium catalyst was demonstrated.
Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
supporting information, p. 5022 - 5037 (2021/05/04)
Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
Photo-Induced ortho-C-H Borylation of Arenes through in Situ Generation of Rhodium(II) Ate Complexes
Araujo Dias, Ant?nio Junio,Nagashima, Yuki,Tanaka, Jin,Tanaka, Ken
supporting information, p. 11325 - 11331 (2021/08/03)
Photoinduced in situ "oxidation"of half-sandwich metal complexes to "high-valent"cationic metal complexes has been used to accelerate catalytic reactions. Here, we report the unprecedented photoinduced in situ "reduction"of half-sandwich metal [Rh(III)] complexes to "low-valent"anionic metal [Rh(II)] ate complexes, which facilitate ligand exchange with electron-deficient elements (diboron). This strategy was realized by using a functionalized cyclopentadienyl (CpA3) Rh(III) catalyst we developed, which enabled the basic group-directed room temperature ortho-C-H borylation of arenes.
Role of hemilabile diamine ligands in the amine-directed C-H borylation of arenes
Hale, Lillian V. A.,McGarry, Kathryn A.,Ringgold, Marissa A.,Clark, Timothy B.
supporting information, p. 51 - 55 (2015/01/30)
A study of the role played by the bidentate ligand used in amine-directed C-H borylation is described. Both reaction conversion and selectivity were significantly impacted when steric congestion and electronic perturbations of the bidentate diamine ligand were made, but a more significant influence was imparted by reducing the bite angle of the ligand. N-Benzylaminopyridine was identified as a general ligand that improves both selectivity and yield for most problematic substrates previously reported with picolylamine as ligand.
Iridium-catalyzed, substrate-directed C-H borylation reactions of benzylic amines
Roering, Andrew J.,Hale, Lillian V. A.,Squier, Phillip A.,Ringgold, Marissa A.,Wiederspan, Emily R.,Clark, Timothy B.
supporting information; experimental part, p. 3558 - 3561 (2012/08/29)
The iridium-catalyzed arene C-H borylation reaction of benzylic amines has been developed, which inverts the typical steric-controlled product distribution to provide ortho-substituted boronate esters. Picolylamine was found to be an ideal ligand to replace 4,4′-di-tert-butylbipyridine to induce the directing effect. Preliminary experiments are consistent with a mechanism involving dissociation of one amine of the hemilabile diamine ligand.
