Rhodium(III)‐Catalyzed Oxidative CH Functionalization of Azomethine Ylides

Zhen, Wencui; Wang, Fen; Zhao, Miao; Du, Zhengyin; Li, Xingwei

doi:10.1002/ange.201207204

Cited by 38 publications

(7 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 H and 13 C NMR and mass spectrum analysis of 7 pointed to cyclometalation. Although a number examples of acyl–rhodium(III) complexes have been isolated by starting from Rh I catalysts,22 reports of stable isolated organorhodium(III) intermediates from Rh III catalysts by deprotonation are still limited,14c, 16c, e, 19a, 23 particularly for acyl–rhodium(III) intermediates 24. Complex 7 catalyzed the amidation reaction of 1 a to give 3 a in 82 % yield (Scheme d), demonstrating the plausibility of 7 as an intermediate in the catalytic cycle.…”

Section: Methodsmentioning

confidence: 99%

Rhodium‐Catalyzed Synthesis of Amides from Aldehydes and Azides by Chelation‐Assisted CH Bond Activation

Yang

Shi

Feng

et al. 2013

Chemistry A European J

View full text Add to dashboard Cite

CH activation: A RhIII‐catalyzed direct aldehyde CH amidation has been achieved with sulfonyl, aryl, and alkyl azides as the amine sources, and release of N2 as the only byproduct (see scheme). More importantly, this catalytic reaction proceeds in the absence of external oxidants or additives, under mild conditions, at neutral pH under air. This reaction represents a new avenue for practical intermolecular CN bond formation by aldehyde CH bond activation. Cp*=1,2,3,4,5‐Pentamethylcyclopentadiene

show abstract

Section: Methodsmentioning

confidence: 99%

Rhodium‐Catalyzed Synthesis of Amides from Aldehydes and Azides by Chelation‐Assisted CH Bond Activation

Yang

Shi

Feng

et al. 2013

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…To overcome the limitation of DGs in simple nucleophilic cyclization reactions, we designed azomethine imines as arene substrates that reacted with diverse selectivity (Scheme ) . The oxidative coupling of benzaldehyde-derived azomethine imines with activated olefins occurred via C–H activation and C–N cleavage to give 1,2-dihydrophthalazines (Scheme a).…”

Section: Activation Of Arene Substratesmentioning

confidence: 99%

Substrate Activation Strategies in Rhodium(III)-Catalyzed Selective Functionalization of Arenes

2015

Self Cite

View full text Add to dashboard Cite

The possibility of developing new methods for the efficient construction of organic molecules via disconnections other than traditional functional group transformations has driven the interest in direct functionalization of C-H bonds. The ubiquity of C-H bonds makes such transformations attractive, but they also pose several challenges. The first is the reactivity and selectivity of C-H bonds. To achieve this, directing groups (DGs) are often installed that can enhance the effective concentration of the catalyst, leading to thermodynamically stable metallacyclic intermediates. However, the presence of a pendant directing group in the product is often undesirable and unnecessary. This may account for the limitation of applications of C-H functionalization reactions in more common and general uses. Thus, the development of removable or functionalizable directing groups is desirable. Another key problem is that the reactivity of the resulting M-C bond can be low, which may limit the scope of the coupling partners and hence limit the reaction patterns of C-H activation reactions. While the first Cp*Rh(III)-catalyzed C-H activation of arenes was reported only 7 years ago, significant progress has been made in this area in the past few years. We began our studies in this area in 2010, and we and others have demonstrated that diversified catalytic functionalization of arenes can be realized using Cp*Rh(III) complexes with high reactivity, stability, and functional group compatibility. This Account describes our efforts to solve some of these challenges using Rh(III) catalysis. We fulfilled our design and activation of the arene substrates by taking advantage of the nucleophilicity, electrophilicity, oxidizing potential, and properties of a participating ligand of the directing groups when the arenes are coupled with relatively reactive unsaturated partners such as alkenes and alkynes. These in situ funtionalizable roles of the DG allowed extensive chemical manipulation of the initial coupled product, especially in the construction of a diverse array of heterocycles. In the coupling of arenes with polar coupling partners, the polar Rh(III)-C(aryl) bond showed higher reactivity as both an organometallic reagent and a nucleophilic aryl source. The polar coupling partners were accordingly activated by virtue of umpolung, ring strain, and rearomatization. All of these transformations have been made possible by integration of the higher reactivity, stability, and compatibility of Rh(III)-C bonds into catalytic systems. We have demonstrated that to date some of these transformations can be achieved only under rhodium catalysis. In addition, by means of stoichiometric reactions, we have gained mechanistic insights into the interactions between the Rh-C bond and the other coupling partners, which have opened new avenues in future direct C-H functionalization reactions.

show abstract

“…As presented in Scheme , the oxidative CH olefination of arenes with N , N ‐cyclic azomethine imines 225 could be catalyzed by a rhodium salt. The N , N ‐cyclic azomethine imine part in the starting material was proposed to be the directing group during the olefination process 88. The olefinated N , N ‐cyclic azomethine imine would go through a cleavage of the CN bond in the pyrazolidinone ring.…”

Section: Other Reactions Of N‐imide Ylidesmentioning

confidence: 99%

Graphene Nanoplatelets: Electrochemical Properties and Applications for Oxidation of Endocrine‐Disrupting Chemicals

Wan

Cai

Liu

et al. 2013

Chemistry A European J

View full text Add to dashboard Cite

In most graphene-based electrochemical applications, graphene nanoplatelets (GNPs) have been applied. Now, for the first time, electrochemical properties of GNPs, namely, its electrochemical activity, potential window, and double-layer capacitance, have been investigated. These properties are compared with those of carbon nanotubes (CNTs). GNP- and CNT-coated electrodes were then applied for electrochemical oxidation of endocrine-disrupting chemicals. The GNP-coated electrode was characterized by atomic force microscopy and electrochemical techniques. Compared with the CNT-coated electrode, higher peak current for the oxidation of 4-nonylphenol is achieved on the GNP-coated electrode, together with lower capacitive current. Electrochemical oxidation of 2,4-dichlorophenol, bisphenol A, and octylphenol in the absence or presence of 4-nonylphenol was studied on the GNP-coated electrode. The results suggest that GNPs have better electrochemical performance than CNTs and are thus more promising for electrochemical applications, for example, electrochemical detection and removal of endocrine-disrupting chemicals.

show abstract

Rhodium(III)‐Catalyzed Oxidative CH Functionalization of Azomethine Ylides

Abstract: Ringe à la carte: Ein Rhodium(III)‐Komplex katalysiert die oxidative Kupplung von Azomethiniminen mit Olefinen. Je nach Reaktionsbedingungen gelingt damit die Synthese von 1,2‐Dihydrophthalazinen, olefinierten Aldehyden oder anellierten Pyridinen.

Cited by 38 publications

References 63 publications

Rhodium‐Catalyzed Synthesis of Amides from Aldehydes and Azides by Chelation‐Assisted CH Bond Activation

Rhodium‐Catalyzed Synthesis of Amides from Aldehydes and Azides by Chelation‐Assisted CH Bond Activation

Substrate Activation Strategies in Rhodium(III)-Catalyzed Selective Functionalization of Arenes

Graphene Nanoplatelets: Electrochemical Properties and Applications for Oxidation of Endocrine‐Disrupting Chemicals

Contact Info

Product

Resources

About