[Ir4(CO)12]-Catalyzed Coupling Reaction of Imidazoles with Aldehydes in the Presence of a Hydrosilane to Give 2-Substituted Imidazoles

Fukumoto, Yoshiya; Sawada, Katsutoshi; Hagihara, Masahiko; Chatani, Naoto; Murai, Shinji

doi:10.1002/1521-3757(20020802)114:15<2903::aid-ange2903>3.0.co;2-o

Cited by 31 publications

(7 citation statements)

References 5 publications

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“…To enable transition metal-catalyzed C–H bond additions to aldehydes, several strategies have been developed to overcome the inherent reversibility of this transformation. In seminal reports, the reversibly formed Ir-catalyzed alcohol addition products were captured as silyl ethers, 6 and this approach has now been extended to Mn, and Re. Trapping of alcohol addition products via irreversible in situ oxidation to the corresponding ketone has also been achieved, and significant progress has been accomplished for Pd and Rh catalysis.…”

Section: Aldehydesmentioning

confidence: 99%

“…6 The authors demonstrated that [Ir 4 (CO) 12 ] catalyzes the coupling of N -methylimidazole, 13 , and aldehydes in the presence of diethylmethylsilane to provide silyl protected alcohols 14 . Interestingly, dimethyl acetylenedicarboxylate (DMAD) as an additive significantly improved the reaction yield, which the authors proposed acts either as a hydrogen acceptor or a ligand.…”

Section: Aldehydesmentioning

confidence: 99%

“…6 The reaction was an extension of their strategy for Ir-catalyzed coupling of N -methylimidazole and aldehydes in the presence of silane to provide silyl protected ethers (See section 2.3.1, Scheme 8). The conditions developed for aldehydes were directly applied to the coupling of N -methylimidazole and propyl isocyanate to provide the corresponding amide 220 in 55% yield.…”

Section: Isocyanatesmentioning

confidence: 99%

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Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

2016

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The transition metal-catalyzed addition of C–H bonds to carbonyls, imines and related polarized π-bonds has emerged as a particularly efficient and powerful approach for the construction of an incredibly diverse array of heteroatom substituted products. Readily available and stable inputs are typically employed, and reactions often proceed with very high functionality group compatibility and without the production of waste byproducts. Additionally, many transition metal-catalyzed C–H bond additions to polarized π-bonds occur within cascade reaction sequences to provide rapid access to a diverse array of different heterocyclic as well as carbocyclic products. This review highlights the diversity of transformations that have been achieved, catalysts that have been used, and types of products that have been prepared through the transition metal catalyzed addition of C–H bonds to carbonyls, imines and related polarized π-bonds.

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Section: Aldehydesmentioning

confidence: 99%

Section: Aldehydesmentioning

confidence: 99%

Section: Isocyanatesmentioning

confidence: 99%

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Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

2016

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“…8 This transformation provides a convenient synthetic route for chiral 3-substituted 3-hydroxy-2-oxindole derivatives with asymmetric induction. While some pioneering works have been reported, 9 only limited mechanistic information is available for aryl sp 2 C−H bond addition to carbonyl groups. Herein, we report the results of mechanistic studies of our newly developed intramolecular enantioselective hydroarylation reaction.…”

Section: ■ Introductionmentioning

confidence: 67%

Scope and Mechanistic Studies of the Cationic Ir/Me-BIPAM-Catalyzed Asymmetric Intramolecular Direct Hydroarylation Reaction

Shirai

Yamamoto

2015

Organometallics

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Results of mechanistic studies on asymmetric hydroarylation of α-keto amides via direct C−H bond addition to a carbonyl group catalyzed by a cationic Ir/Me-BIPAM complex are presented in this paper. A catalytic cycle involving C−H bond cleavage to give an Ar-[Ir] + intermediate, insertion of a carbonyl group into the aryl-iridium bond, giving iridium alkoxide, and finally reductive elimination to reproduce active [Ir] + species is proposed. The mechanistic insight for the iridium hydride species indicated that the C−H bond cleavage is caused in a reversible manner. Furthermore, the kinetic isotope effect was measured by product analysis of the reaction to compare H/D, and it was determined that k H /k D was 1.85. These experimental results suggest that the C−H bond cleavage step is not included in the turnover-limiting step. In addition, Hammett studies of substrates (ρ = −0.99) demonstrated that electron-donating groups at the para position to the reactive C−H bond accelerate the reaction rate. This linear relationship obtained in the Hammett plot indicates that the nucleophilicity of the aryl-iridium intermediate is an important factor in this reaction. All of the data indicate that carbonyl insertion into aryl-iridium is included in the turnover-limiting step of the catalytic cycle.

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“…In recent years, chemists have been struggling in this field and have made significant contributions 2. The beautiful example of C–H addition to aldehydes with the assistance of a silane was reported by Murai and co‐workers 3. Later on, the silane‐assisted strategy was further extended by Takai4 and our group5 in different systems.…”

Section: Introductionmentioning

confidence: 93%

Aromatic C–H Addition to Ketones: The Effect of Directing Groups

et al. 2013

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The first example of the transition‐metal‐catalyzed direct intermolecular C–H bond addition to ketones was achieved by using a rhodium catalyst. A significant influence of the directing group on the reactivity was observed, and sterically more hindered directing groups could promote the reaction. In addition, intermolecular hydrogen bonding played a role in stabilizing the product. The substrate scope for the quinoline derivatives was very good.

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[Ir4(CO)12]-Catalyzed Coupling Reaction of Imidazoles with Aldehydes in the Presence of a Hydrosilane to Give 2-Substituted Imidazoles

Abstract: Eine deutliche Ausbeutesteigerung bewirkt die Zugabe von Acetylendicarbonsäuredimethylester (DMAD) bei der Reaktion von 1‐Methylimidazol 1 mit Aldehyden 2 und Diethylmethylsilan in Gegenwart von [Ir4(CO)12] als Katalysator, die zu 2‐(1‐Diethylmethylsiloxyalkyl)imidazolen 3 führt.

Cited by 31 publications

References 5 publications

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

Transition-Metal-Catalyzed C–H Bond Addition to Carbonyls, Imines, and Related Polarized π Bonds

Scope and Mechanistic Studies of the Cationic Ir/Me-BIPAM-Catalyzed Asymmetric Intramolecular Direct Hydroarylation Reaction

Aromatic C–H Addition to Ketones: The Effect of Directing Groups

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