- RhCl3·3H2O-Catalyzed C7-Selective C-H Carbonylation of Indolines with CO and Alcohols
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An attractive method for the synthesis of indoline-7-carboxylates through RhCl3-catalyzed C-H carbonylation of indolines with CO and alcohols was developed. The copper-based oxidant and removable pyrimidyl directing group played important roles in achieving high-level yields of the title products. Based on control experiments, a possible catalytic cycle was proposed.
- Du, Rongrong,Zhao, Kang,Liu, Jianhua,Han, Feng,Xia, Chungu,Yang, Lei
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- Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
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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.
- Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
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supporting information
p. 5022 - 5037
(2021/05/04)
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- Noncovalent Interactions in Ir-Catalyzed C-H Activation: L-Shaped Ligand for Para-Selective Borylation of Aromatic Esters
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An efficient strategy for the para-selective borylation of aromatic esters is described. For achieving high para-selectivity, a new catalytic system has been developed modifying the core structure of the bipyridine. It has been proposed that the L-shaped ligand is essential to recognize the functionality of the oxygen atom of the ester carbonyl group via noncovalent interaction, which provides an unprecedented controlling factor for para-selective C-H activation/borylation.
- Hoque, Md Emdadul,Bisht, Ranjana,Haldar, Chabush,Chattopadhyay, Buddhadeb
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supporting information
p. 7745 - 7748
(2017/06/21)
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- Rhodium enalcarbenoids: Direct synthesis of indoles by rhodium(II)- catalyzed [4+2] benzannulation of pyrroles
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Disclosed herein is the design of an unprecedented electrophilic rhodium enalcarbenoid which results from rhodium(II)-catalyzed decomposition of a new class of enaldiazo compounds. The synthetic utility of these enalcarbenoids has been successfully demonstrated in the first transition-metal-catalyzed [4+2] benzannulation of pyrroles, thus leading to substituted indoles. The new benzannulation has been applied to the efficient synthesis of the natural product leiocarpone as well as a potent adipocyte fatty-acid binding protein inhibitor. Fat cat: A new class of enaldiazo compounds resulted in the first transition-metal-catalyzed [4+2] benzannulation of pyrroles to deliver indoles. The benzannulation is proposed to involve an unprecedented diacceptor rhodium enalcarbenoid. The reaction was used in the highly efficient synthesis of the natural product leiocarpone and a potent adipocyte fatty-acid binding protein inhibitor.
- Dawande, Sudam Ganpat,Kanchupalli, Vinaykumar,Kalepu, Jagadeesh,Chennamsetti, Haribabu,Lad, Bapurao Sudam,Katukojvala, Sreenivas
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supporting information
p. 4076 - 4080
(2014/05/06)
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- A new one-pot synthesis of polysubstituted indoles from pyrroles and β-nitroacrylates
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The reaction of β-nitroacrylates with pyrroles, under solvent- and catalyst-free conditions, allows the formation of Friedel-Crafts adducts which, after in situ treatment with Amberlyst 15 in isopropyl alcohol under reflux, provide polysubstituted indoles, via a benzannulation reaction, in a one-pot process. Copyright
- Palmieri, Alessandro,Gabrielli, Serena,Lanari, Daniela,Vaccaro, Luigi,Ballini, Roberto
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experimental part
p. 1425 - 1428
(2011/08/03)
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