Transition Metal Catalyzed Reactions in Organic Synthesis. Part 7. Intramolecular Chromium(II)-Catalyzed Pinacol Cross-Coupling of 2-Methylene-α,ω-dicarbonyls.

ChemInform ◽  
2004 ◽  
Vol 35 (39) ◽  
Author(s):  
Ulrich Groth ◽  
Marc Jung ◽  
Till Vogel
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Cross Coupling ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

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.

Advanced Approaches to Post-Assembly Modification of Peptides by Transition-Metal-Catalyzed Reactions

Synthesis ◽  
2019 ◽  
Vol 51 (09) ◽  
pp. 1913-1922 ◽  
Author(s):  
Sambasivarao Kotha ◽  
Milind Meshram ◽  
Nageswara Panguluri
Keyword(s):  
Transition Metal ◽  
Cross Coupling ◽  
Dipolar Cycloaddition ◽  
Ring Closing Metathesis ◽  
Negishi Coupling ◽  
Peptide Modification ◽  
Modified Peptides ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

We have summarized diverse synthetic approaches for the modification of peptides by employing transition-metal-catalyzed reactions. These methods can deliver unusual peptides suitable for peptidomimetics. To this end, several popular reactions such as Diels–Alder, 1,3-dipolar cycloaddition, [2+2+2] cyclotrimerization, metathesis, Suzuki­–Miyaura cross-coupling, and Negishi coupling have been used to assemble modified peptides by post-assembly chemical modification strategies.1 Introduction2 Synthesis of a Cyclic α-Amino Acid Derivative via a Ring-Closing Metathesis Protocol3 Peptide Modification Using a Ring-Closing Metathesis Strategy4 Peptide Modification via a [2+2+2] Cyclotrimerization Reaction5 Peptide Modification by Using [2+2+2] Cyclotrimerization and Suzuki Coupling6 Peptide Modification via a Suzuki–Miyaura Cross-Coupling7 Peptide Modification via Cross-Enyne Metathesis and a Diels–Alder­ Reaction as Key Steps8 Peptide Modification via 1,3-Dipolar Cycloaddition Reactions9 Modified Peptides via Negishi Coupling10 A Modified Dipeptide via Ethyl Isocyanoacetate11 Conclusions

Transition-metal-catalyzed reactions of carbon-heteroatom bond formation by substitution and addition processes

2005 ◽  
Vol 77 (12) ◽  
pp. 2021-2027 ◽  
Author(s):  
Irina P. Beletskaya
Keyword(s):  
Transition Metal ◽  
Triple Bond ◽  
Bond Formation ◽  
Cross Coupling ◽  
Addition Reactions ◽  
Coupling Reactions ◽  
Cross Coupling Reactions ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Two types of transition-metal-catalyzed cross-coupling reactions, which both lead to the formation of carbon-heteroatom bonds, are considered: RX + E-H and E-X + RM. The potential of addition reactions of E-H or E-E to double or triple bond in C-E bond formation is also demonstrated.

scholarly journals Recent Advances in Transition-Metal-Catalyzed, Directed Aryl C–H/N–H Cross-Coupling Reactions

Synthesis ◽  
2017 ◽  
Vol 49 (20) ◽  
pp. 4586-4598 ◽  
Author(s):  
Martyn Henry ◽  
Mohamed Mostafa ◽  
Andrew Sutherland
Keyword(s):  
Transition Metal ◽  
Bond Formation ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Short Review ◽  
Coupling Reactions ◽  
Dehydrogenative Coupling ◽  
Transition Metal Catalyzed ◽  
Catalyzed Reactions ◽  
Metal Catalyzed

Amination and amidation of aryl compounds using a transition-metal-catalyzed cross-coupling reaction typically involves prefunctionalization or preoxidation of either partner. In recent years, a new class of transition-metal-catalyzed cross-dehydrogenative coupling reaction has been developed for the direct formation of aryl C–N bonds. This short review highlights the substantial progress made for ortho-C–N bond formation via transition-metal-catalyzed chelation-directed aryl C–H activation and gives an overview of the challenges that remain for directed meta- and para-selective reactions.1 Introduction2 Intramolecular C–N Cross-Dehydrogenative Coupling2.1 Nitrogen Functionality as Both Coupling Partner and Directing Group2.2 Chelating-Group-Directed Intramolecular C–N Bond Formation3 Intermolecular C–N Cross-Dehydrogenative Coupling3.1 ortho-C–N Bond Formation3.1.1 Copper-Catalyzed Reactions3.1.2 Other Transition-Metal-Catalyzed Reactions3.2 meta- and para-C–N Bond Formation4 C–N Cross-Dehydrogenative Coupling of Acidic C–H Bonds5 Conclusions

Developments in Organocatalyzed C(Ar)- C(Ar) Bond formation Reactions via Single Electron Transfer Mechanism: An Overview

2021 ◽  
Vol 08 ◽  
Author(s):  
Lalit Yadav ◽  
Sandeep Chaudhary
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Bond Activation ◽  
Bond Formation ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Metal Free ◽  
Cross Coupling Reactions ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

: The formation of new bonds through C-C bond formation is of utmost importance in the synthesis of biologically privileged scaffolds and therapeutic drugs. In recent years, extensive efforts has been done to improve the intermolecular and intramolecular cross-coupling reaction in the simple, mild, efficient, economical, and eco-friendly manner via transition metal-free or organocatalytic direct C-H bond activation methodology. The traditional crosscoupling era continuously shifted to metal-free, organocatalytic, or metal-free cross-dehydrogenative coupling strategies to fast-track the reactions and diminishing the typical purification processes. Therefore, recent advances on the transitionmetal-free, organocatalytic inter- and intra-molecular cross-coupling reactions have been introduced and discussed in the present article. In view of the reaction mechanism, organocatalytic cross-coupling reactions undergo through the radical pathways, radical anionic intermediate which is completely different from traditional transition metal-catalyzed reactions. The exploration of transition metal-free organocatalyzed cross-couplings for direct C-H arylation of arenes has grown significantly, thereby, improving the formation of a wide range of aryl-aryl /aryl-heteroaryl/ heteroaryl-heteroaryl compounds. In the survey, transition metal-free/organocatalytic cross-coupling reactions showed a higher efficiency under simple and mild conditions than the comparative transition metal-catalyzed cross-coupling reactions. However, the higher regioselectivity and chemoselectivity are still far ahead in organocatalytic cross-coupling reactions due to their specific intrinsic mechanistic pathway. The tuning of many parameters such as oxidative states, ligands coordination, and counter anions, etc., which results in the specific direct C-H functionalization with flexible methodology are missing in the transition metal-free cross-coupling reactions. The highly systematic transition metal-catalyzed chemistry is still playing a dominant role over transition metal-free chemistry in organic synthesis. The organocatalyzed transition-metal-free conditions should be more efficient, chemoselective, and regioselective for further potential development and applications in organic synthesis. For the endless pursuit of sustainable chemistry and green chemistry, such transition-metalfree/organocatalytic reactions should be never ceased. Additional curious attention and interest have been developed so far, and chemists are showing their eagerness and talents to uncover the hidden treasure of green chemistry. In this review article, we highlighted the developments of various transition metal-free/organocatalytic C-H bond activation reactions which further encourages the advancement in the development of sustainable C-C coupling reactions and their further applications towards the synthesis of biologically privileged scaffolds and drug molecules.

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