Palladium‐Catalyzed Oxidative Intramolecular CC Bond Formation via Double sp2 CH Activation between the 2‐Position of Imidazoles and a Benzene Ring

Sun, Manman; Wu, Huandong; Zheng, Jianbo; Bao, Weiliang

doi:10.1002/adsc.201100801

Cited by 42 publications

(24 citation statements)

References 64 publications

(13 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although a few reports of intramolecular oxidative couplings are available, including a pioneering study by Greaney et al . (largely in 3‐substituted indoles yielding medium‐ring fused indoles), and subsequently by Bao, Guo, and DeBoef (in benzimidazoles and purines affording benzimidazole fused isoindolines), they are limited to the nitrogen heterocycles that have a substituent or nitrogen– at the 3‐position. Perhaps more importantly, these systems have not been used to prepare halogen‐installed fused isoindolines.…”

Section: Introductionmentioning

confidence: 99%

Intramolecular Oxidative Arylations in 7‐Azaindoles and Pyrroles: Revamping the Synthesis of Fused N‐Heterocycle Tethered Fluorenes

Laha

Bhimpuria

Hunjan

2016

Chemistry A European J

View full text Add to dashboard Cite

We revealed intramolecular oxidative arylations in 7-azaindoles and pyrroles that, for the first time, provided direct access to 7-azaindole- or pyrrole-fused isoindolines and tetrahydroisoquinolines. In addition, N-benzylation of 7-azaindoles or pyrroles with sterically hindered sec-benzyl alcohols by Mitsunobu reaction followed by intramolecular oxidative arylation allowed access to chiral congeners of fused isoindolines that have little precedence. A new opportunity in the design and synthesis of fluorene-based organic emitters is demonstrated in the preparation of novel fused N-heterocycle tethered fluorenes, including a chiral fluorene architecture.

show abstract

Section: Introductionmentioning

confidence: 99%

Intramolecular Oxidative Arylations in 7‐Azaindoles and Pyrroles: Revamping the Synthesis of Fused N‐Heterocycle Tethered Fluorenes

Laha

Bhimpuria

Hunjan

2016

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…[8] Severale xampleso fs uch transformationsh ave been reported. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] Synthesis of heteroatom-containing ladder-type p-conjugated molecules by transition metal-catalyzed oxidative CÀH/CÀH coupling reactions, however,i ss till rare. [23,24] We report herein general palladium-catalyzed intramolecular oxidative CÀH/CÀH coupling reactions between heteroaromatic and aromatic rings, and its application to the synthesis of several classes of heteroatom-containing ladder-type p-conjugated molecules (Figure 2e).…”

mentioning

confidence: 99%

“…Reaction of 1-biphenylbenzimidazole (1b)u nder the optimized reaction conditions gave al adder-type product 2b in 88 %y ield. [22] When using biphenyl-substituted heteroaromatic compounds as substrates, such as imidazole, indole, benzothiophene, andb enzofuran, the corresponding p-conjugated molecules 2c-2e wereo btained in moderate to good yields. [25] The reaction conditions in Ta ble 1w ere appliedt ot he synthesis of heteroatom-or carbonyl-bridged ladder-type molecules ( Table 2).…”

mentioning

confidence: 99%

Palladium‐Catalyzed Construction of Heteroatom‐Containing π‐Conjugated Systems by Intramolecular Oxidative CH/CH Coupling Reaction

Saito

Chikkade

Kanai

et al. 2015

Chemistry A European J

View full text Add to dashboard Cite

Synthesis of heteroatom-containing ladder-type π-conjugated molecules was successfully achieved via a palladium-catalyzed intramolecular oxidative C-H/C-H cross-coupling reaction. This reaction provides a variety of π-conjugated molecules bearing heteroatoms, such as nitrogen, oxygen, phosphorus, and sulfur atoms, and a carbonyl group. The π-conjugated molecules were synthesized efficiently, even in gram scale, and larger π-conjugated molecules were also obtained by a double C-H/C-H cross-coupling reaction and successive oxidative cycloaromatization.

show abstract

“…Similarly, the construction of the C-C bond between imidazoles and simple benzene rings via the intramolecular oxidative coupling catalyzed by PdCl 2 was also reported [17]. Activation of the acidic C-H bond between two nitrogen atoms followed by the oxidative addition of benzene facilitates the produce of desired tricycle 42 in excellent 96% yield (Scheme 10).…”

Section: Pd-catalyzed Annulation Reactionsmentioning

confidence: 78%

Double C–H Activation for the C–C bond Formation Reactions

Liu

Xiong

Chen

et al. 2018

COS

View full text Add to dashboard Cite

Background: Among the numerous bond-forming patterns, C–C bond formation is one of the most useful tools for building molecules for the chemical industry as well as life sciences. Recently, one of the most challenging topics is the study of the direct coupling reactions via multiple C–H bond cleavage/activation processes. A number of excellent reviews on modern C–H direct functionalization have been reported by Bergman, Bercaw, Yu and others in recent years. Among the large number of available methodologies, Pdcatalyzed reactions and hypervalent iodine reagent mediated reactions represent the most popular metal and non-metal involved transformations. However, the comprehensive summary of the comparison of metal and non-metal mediated transformations is still not available. Objective: The review focuses on comparing these two types of reactions (Pd-catalyzed reactions and hypervalent iodine reagent mediated reactions) based on the ways of forming new C–C bonds, as well as the scope and limitations on the demonstration of their synthetic applications. Conclusion: Comparing the Pd-catalyzed strategies and hypervalent iodine reagent mediated methodologies for the direct C–C bond formation from activation of C-H bonds, we clearly noticed that both strategies are powerful tools for directly obtaining the corresponding pruducts. On one hand, the hypervalent iodine reagents mediated reactions are normally under mild conditions and give the molecular diversity without the presence of transition-metal, while the Pd-catalyzed approaches have a broader scope for the wide synthetic applications. On the other hand, unlike Pd-catalyzed C-C bond formation reactions, the study towards hypervalent iodine reagent mediated methodology mainly focused on the stoichiometric amount of hypervalent iodine reagent, while few catalytic reactions have been reported. Meanwhile, hypervalent iodine strategy has been proved to be more efficient in intramolecular medium-ring construction, while there are less successful examples on C(sp3)–C(sp3) bond formation. In summary, we have demonstrated a number of selected approaches for the formation of a new C–C bond under the utilization of Pd-catalyzed reaction conditions or hyperiodine reagents. The direct activations of sp2 or sp3 hybridized C–H bonds are believed to be important strategies for the future molecular design as well as useful chemical entity synthesis.

show abstract

Palladium‐Catalyzed Oxidative Intramolecular CC Bond Formation via Double sp² CH Activation between the 2‐Position of Imidazoles and a Benzene Ring

Cited by 42 publications

References 64 publications

Intramolecular Oxidative Arylations in 7‐Azaindoles and Pyrroles: Revamping the Synthesis of Fused N‐Heterocycle Tethered Fluorenes

Intramolecular Oxidative Arylations in 7‐Azaindoles and Pyrroles: Revamping the Synthesis of Fused N‐Heterocycle Tethered Fluorenes

Palladium‐Catalyzed Construction of Heteroatom‐Containing π‐Conjugated Systems by Intramolecular Oxidative CH/CH Coupling Reaction

Double C–H Activation for the C–C bond Formation Reactions

Contact Info

Product

Resources

About