scholarly journals Oxidizing agents in metal-catalyzed and metal-free C-H functionalization of heteroarenes.

ARKIVOC ◽  
2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Irina Alexandrovna Utepova ◽  
Oleg Nikolaevich Chupakhin ◽  
Maria Alexandrovna Trestsova ◽  
Alexandra Alexandrovna Musikhina ◽  
Alexandr Alexandrovich Shchepochkin ◽  
...  
Synthesis ◽  
2021 ◽  
Author(s):  
Heather Lam ◽  
Mark Lautens ◽  
Xavier Abel-Snape ◽  
Martin F. Köllen

Abstract(4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and a 3-atom synthon to form both 7-membered carbocycles as well as heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis and Brønsted acids as well as some rare examples of boronic acid catalysis and photocatalysis. In analogy to our previous review, we exclude annulations involving cyclic dienes like furan, pyrrole, cyclohexadiene or cyclopentadiene, as Chiu, Harmata, Fernándes and others have recently published reviews encompassing such substrates. We will however discuss the recent additions (2010–2020) to the literature on (4+3)-annulations involving other types of 4-atom-synthons.1 Introduction2 Bases3 Annulations Using N-Heterocyclic Carbenes3.1 N-Heterocyclic Carbenes (NHCs)3.2 N-Heterocyclic Carbenes and Base Dual-Activation4 Phosphines5 Acids5.1 Lewis Acids5.2 Brønsted Acids6 Boronic Acid Catalysis and Photocatalysis7 Conclusion


Synthesis ◽  
2021 ◽  
Author(s):  
Leonid Fershtat ◽  
Fedor Teslenko

Five-membered heterocyclic N-oxides attracted special attention due to their strong application potential in medicinal chemistry and advanced materials science. In this regard, novel methods for their synthesis and functionalization are constantly required. In this short review, recent state-of-the-art achievements in the chemistry of isoxazoline N-oxides, 1,2,3-triazole 1-oxides and 1,2,5-oxadiazole 2-oxides are briefly summarized. Main routes to transition-metal-catalyzed and metal-free functionalization protocols along with mechanistic considerations are outlined. Transformation patterns of the hetarene N-oxide rings as precursors to other nitrogen heterocyclic systems are also presented.


2020 ◽  
Vol 8 ◽  
Author(s):  
Naoko Takenaga ◽  
Ravi Kumar ◽  
Toshifumi Dohi

In recent years, the chemistry of heteroaryliodonium(III) salts has undergone significant developments. Heteroaryliodonium(III) salts have been found to be useful synthetic tools for the transfer of heteroaryl groups under metal-catalyzed and metal-free conditions for the preparation of functionalized heteroarene-containing compounds. Synthetic transformations mediated by these heteroaryliodonium(III) salts are classified into two categories: (1) reactions utilizing the high reactivity of the hypervalent iodine(III) species, and (2) reactions based on unique and new reactivities not observed in other types of conventional diaryliodonium salts. The latter feature is of particular interest and so has been intensively investigated in recent decades. This mini-review therefore aims to summarize the recent synthetic applications of heteroaryliodonium(III) salts as highly reactive electrophiles.


Synthesis ◽  
2018 ◽  
Vol 50 (11) ◽  
pp. 2131-2149 ◽  
Author(s):  
Kamal Kapoor ◽  
Parthasarathi Das ◽  
Rajni Khajuria ◽  
Sk. Rasheed ◽  
Chhavi Khajuria

Pyrido[1,2-a]benzimidazole is one of the most important azaheterocyclic compounds consisting of three fused aromatic rings. Molecules containing this core have displayed a wide range of applications in the field of medicinal chemistry. The synthesis of pyrido[1,2-a]benzimidazole and its derivatives has attracted organic chemists because of its tremendous utility in interdisciplinary branches of chemistry. In this context, this review discusses the main advances in the synthesis of pyrido[1,2-a]benzimidazoles via metal-mediated and metal-free reactions from 2000 to 2016.1 Introduction2 Synthetic Approaches to Pyrido[1,2-a]benzimidazoles2.1 Type I: Transition-Metal-Catalyzed Methods2.2 Type II: Metal-Free Approaches3 Conclusion


2021 ◽  
Vol 14 (8) ◽  
pp. 779
Author(s):  
Kena Zhang ◽  
Christine Tran ◽  
Mouad Alami ◽  
Abdallah Hamze ◽  
Olivier Provot

This review concerns the synthesis and biological activities of pyrazino[1,2-a]indoles and pyrazino[1,2-a]indol-1-ones reported since 1997 and the discovery of biological activity of pyrazinoindole derivatives. In the first part, we first presented the synthetic routes that have been reported from a methodological point of view to access the pyrazinoindole unit according to cyclization reactions using or not using metal catalysts. Then, syntheses and neuropsychiatric, auto-immune, anti-infectious and anti-cancer properties of pyrazinoindoles were detailed. In the second part, we first reported the main accesses to pyrazinoindol-1-one substrates according to Michael reactions, metal-catalyzed and metal-free cyclization reactions. The syntheses and anti-cancer, anti-infectious, anti-allergenic and neuropsychiatric properties of pyrazinoindolones were next described and discussed.


2017 ◽  
Vol 15 (2) ◽  
pp. 285-300 ◽  
Author(s):  
K. Kubota ◽  
H. Iwamoto ◽  
H. Ito

Recent advances in borylations of organic halides, including both transition-metal-catalyzed and metal-free methods are summarized. Borylative cyclization is also discussed.


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