scholarly journals Construction 7-Membered Ring via Ni-Al Bimetal-Enabled C-H Cyclization for Synthesis of Tricyclic Imidazoles

2021 ◽  
Author(s):  
Mengchun Ye ◽  
Jiang-Fei Li ◽  
Wei-Wei Xu ◽  
Rong-Hua Wang ◽  
Yue Li ◽  
...  
Keyword(s):  
Transition Metal ◽  
Membered Ring ◽  
Bioactive Molecules ◽  
Direct Construction ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
Medium Ring ◽  
Ring Synthesis

Abstract The construction of 7-membered ring via direct C7−H cyclization of benzoimidazoles with alkenes would provide a more atom- and step economical route to tricyclic imidazoles and derivatives that widely exist in a broad range of bioactive molecules. However, transition metal-catalyzed C−H cyclization for medium-ring synthesis has been limited to reactive C−H bonds, instead, the activation of unreactive C−H bonds towards medium synthesis still remains an elusive challenge. Herein, we report a direct construction of 7-membered rings via Ni−Al co-catalyzed unreactive C7−H cyclization of benzoimidazoles with alkenes, providing a series of tricyclic imidazoles in 40−98% yield and with up to 95:5 er.

scholarly journals Construction 7-membered ring via Ni–Al bimetal-enabled C–H cyclization for synthesis of tricyclic imidazoles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jiang-Fei Li ◽  
Wei-Wei Xu ◽  
Rong-Hua Wang ◽  
Yue Li ◽  
Ge Yin ◽  
...  
Keyword(s):  
Transition Metal ◽  
Membered Ring ◽  
Bioactive Molecules ◽  
Direct Construction ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
Medium Ring ◽  
Ring Synthesis

AbstractThe construction of 7-membered ring via direct C7–H cyclization of benzoimidazoles with alkenes would provide a more atom- and step-economical route to tricyclic imidazoles and derivatives that widely exist in a broad range of bioactive molecules. However, transition metal-catalyzed C–H cyclization for medium-ring synthesis has been limited to reactive C–H bonds, instead, the activation of unreactive C–H bonds towards medium synthesis still remains an elusive challenge. Herein, we report a direct construction of 7-membered rings via Ni–Al co-catalyzed unreactive C7–H cyclization of benzoimidazoles with alkenes, providing a series of tricyclic imidazoles in 40–98% yield and with up to 95:5 er.

scholarly journals Recent Advances in the Development of Catalytic Methods that Construct Medium-Ring Lactams, Partially Saturated Benzazepines and Their Derivatives

Synthesis ◽  
2021 ◽  
Author(s):  
Tom G. Driver ◽  
Wrickban Mazumdar
Keyword(s):  
Transition Metal ◽  
Multicomponent Reactions ◽  
Beckmann Rearrangement ◽  
Partially Saturated ◽  
Recent Advances ◽  
Transition Metal Catalyzed ◽  
Rearrangement Reactions ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Medium Ring

AbstractRecent catalytic methods to construct medium-sized lactams­ and partially saturated benzazepines and their derivatives are surveyed. The review is divided into the following sections:1 Introduction2 Non-Transition-Metal-Catalyzed Reactions2.1 Beckmann Rearrangement2.2 Non-Beckmann Rearrangement Reactions2.3 Multicomponent reactions3 Transition-Metal-Catalyzed Reactions3.1 Gold-Catalyzed Reactions to Access Medium-Sized N-Hetero­cycles3.2 Reactions Involving a Metal η3-Complex Catalytic Intermediate3.3 Transition-Metal-Catalyzed Reactions of Strained Cycloalkanes4 Conclusions

scholarly journals Transition Metal and Inner Transition Metal Catalyzed Amide Derivatives Formation through Isocyanide Chemistry

Synthesis ◽  
2020 ◽  
Vol 52 (21) ◽  
pp. 3162-3188
Author(s):  
Morteza Shiri ◽  
Noushin Farajinia-Lehi ◽  
Parvin Salehi ◽  
Zahra Tanbakouchian
Keyword(s):  
Transition Metal ◽  
Current Trend ◽  
Research Area ◽  
Bioactive Molecules ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Amide Derivatives ◽  
Coordination Ability ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

AbstractThe synthesis of amides is a substantial research area in organic chemistry because of their ubiquitous presence in natural products and bioactive molecules. The use of easily accessible isocyanides as amidoyl (carbamoyl) synthons in cross-coupling reactions using transition metal and inner transition metöal catalysts is a current trend in this area. Isocyanides, owing to their coordination ability as a ligand and inherent electronic properties for reactions with various partners, have expanded the potential application of these transformations for the preparation of novel synthetic molecules and pharmaceutical candidates. This review gives an overview of the achievements in isocyanide-based transition metal and inner transition metal catalyzed amide formation and discusses highlights of the proposed distinct mechanisms.1 Introduction2 Synthesis of Arenecarboxamides3 Synthesis of Alkanamides4 Synthesis of Cyclic Amides5 Formation of Alkynamides6 Formation of Acrylamide-like Molecules7 Formation of Ureas and Carbamates8 Conclusion

Transition Metal Catalyzed C-H bond Activation/Functionalization and Annulation of Phthalazinones

2021 ◽  
Author(s):  
Chandrasekaran Sivaraj ◽  
Alagumalai Ramkumar ◽  
Nagesh Sankaran ◽  
THIRUMANAVELAN GANDHI
Keyword(s):  
Natural Products ◽  
Transition Metal ◽  
Bond Activation ◽  
Bioactive Molecules ◽  
Structural Motifs ◽  
The Past ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phthalazinones and their higher congeners are commonly prevalent structural motifs that occur in natural products, bioactive molecules, and pharmaceuticals. In the past few decades transition metal-catalyzed reactions have received an...

Transition-metal-catalyzed cleavage of carbon–selenium bond and addition to alkynes and allenes

2010 ◽  
Vol 82 (3) ◽  
pp. 565-575 ◽  
Author(s):  
Shin-ichi Fujiwara ◽  
Masashi Toyofuku ◽  
Hitoshi Kuniyasu ◽  
Nobuaki Kambe
Keyword(s):  
Transition Metal ◽  
Membered Ring ◽  
Ring Formation ◽  
Reaction Pathways ◽  
Unsaturated Hydrocarbons ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed ◽  
High Stereoselectivity

This account summarizes our recent results on transition-metal-catalyzed cleavage of C–Se bond and addition to unsaturated hydrocarbons such as alkynes and allenes. Pd(0)-catalyzed intramolecular carbamoselenation of alkynes forms four- to eight-membered α-alkylidenelactams. Interestingly, four-membered ring formation is faster than five- and six-membered ring formation. Intramolecular vinylselenation of suitably structured alkynes offers pathways to conjugated δ-lactam frameworks. Electron-withdrawing groups on the vinyl moiety are essential to promote this reaction. Intermolecular 1,2-addition of selenol esters onto allenes proceeds with excellent regioselectivity and high stereoselectivity in the presence of a Pd(0) catalyst, producing functionalized allyl selenides. In addition, Pd(0)-catalyzed intramolecular selenocarbamoylation of allenes gives α,β-unsaturated γ- and δ-lactams with perfect regioselectivity. The scope and limitations, as well as reaction pathways, are discussed.

Chelation-assisted transition metal-catalysed C–H chalcogenylations

2020 ◽  
Vol 7 (8) ◽  
pp. 1022-1060 ◽  
Author(s):  
Wenbo Ma ◽  
Nikolaos Kaplaneris ◽  
Xinyue Fang ◽  
Linghui Gu ◽  
Ruhuai Mei ◽  
...  
Keyword(s):  
Transition Metal ◽  
Recent Advances ◽  
Site Selectivity ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

This review summarizes recent advances in C–S and C–Se formations via transition metal-catalyzed C–H functionalization utilizing directing groups to control the site-selectivity.

Monodentate Trialkylphosphines: Privileged Ligands in Metal-catalyzed Crosscoupling Reactions

2020 ◽  
Vol 24 (3) ◽  
pp. 231-264 ◽  
Author(s):  
Kevin H. Shaughnessy
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Wide Range ◽  
Sterically Demanding ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Phosphines are widely used ligands in transition metal-catalyzed reactions. Arylphosphines, such as triphenylphosphine, were among the first phosphines to show broad utility in catalysis. Beginning in the late 1990s, sterically demanding and electronrich trialkylphosphines began to receive attention as supporting ligands. These ligands were found to be particularly effective at promoting oxidative addition in cross-coupling of aryl halides. With electron-rich, sterically demanding ligands, such as tri-tertbutylphosphine, coupling of aryl bromides could be achieved at room temperature. More importantly, the less reactive, but more broadly available, aryl chlorides became accessible substrates. Tri-tert-butylphosphine has become a privileged ligand that has found application in a wide range of late transition-metal catalyzed coupling reactions. This success has led to the use of numerous monodentate trialkylphosphines in cross-coupling reactions. This review will discuss the general properties and features of monodentate trialkylphosphines and their application in cross-coupling reactions of C–X and C–H bonds.

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