SELENIUM AS A VERSATILE REAGENT IN ORGANIC SYNTHESIS: MORE THAN ALLYLIC OXIDATION

2021 ◽  
Vol 18 ◽  
Author(s):  
Samuel Thurow ◽  
Laura Abenante ◽  
João Marcos Anghinoni ◽  
Eder João Lenardão

: For many years since its discovery, Selenium has played the role of a bad boy who became a hero in organic transformations. Selenium dioxide, for instance, is one of the most remembered reagents in allylic oxidations, having been applied in the synthesis of several naturally occurring products. The main goal of this review is to show the recent advances in the use of classical and new selenium reagents in organic synthesis. As demonstrated through around 60 references discussed in this study, selenium can go even forward as a versatile reagent. We bring a collection of selenium reagents and their transformations that are still hidden from most synthetic organic chemists.

Synthesis ◽  
2017 ◽  
Vol 50 (04) ◽  
pp. 711-722 ◽  
Author(s):  
Xiaodong Jia ◽  
Pengfei Li

tert-Butyl nitrite (TBN) is an important metal-free reagent that is widely applied in various organic transformations. Besides its traditional applications in nitrosation and diazotization, its ability to activate molecular oxygen to enable the initiation of radical reactions, including nitration, oximation, oxidation, and so on, has attracted extensively attention in the past decade. This review highlights recent advances in this field to promote further exploration of this versatile compound.1 Introduction2 Reactions Involving TBN2.1 Nitrosation2.2 Oximation2.3 Diazotization2.4 Nitration2.5 Oxidation2.6 Other Reactions3 Conclusion and Perspective


2021 ◽  
Vol 25 ◽  
Author(s):  
Rashid Ali ◽  
Ajay Kumar Chinnam ◽  
Vikas R. Aswar

: The deep eutectic mixtures (DESs), introduced as novel alternative to usual volatile organic solvents for organic transformations has attracted a tremendous attention of the research community because of their low cost, negligible vapour pressure, low toxicity, biodegradability, recyclability, insensitive towards moisture, and readily availability from bulk renewable resources. Although, the low melting mixture of dimethyl urea (DMU)/L-(+)-tartaric acid (TA) is still infancy yet much effective as it play double and triple roles such as solvent, catalyst and/or reagent in a same pot for many crucial organic transformations. These unique properties of DMU/TA mixture prompted us to provide a quick overview of where the field stands presently, and where it might be going in near future. To our best knowledge, no review dealing with the applications of a low melting mixture of DMU/TA appeared in the literature except the one published in 2017 describing only the chemistry of indole systems. Therefore, we intended to reveal the developments of this versatile low melting mixture in the modern organic synthesis since its first report in 2011 by Köenig’s team to till date. Hopefully, the present review article will be useful to the researcher working not only in the arena of synthetic organic chemistry but also to the scientists working in other branches of science and technology.


Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1429
Author(s):  
Manas Sutradhar

The role of catalysts is extremely important for various organic transformations and the synthesis of organic compounds [...]


Photochem ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 237-246
Author(s):  
Vishal Srivastava ◽  
Pravin K. Singh ◽  
Arjita Srivastava ◽  
Surabhi Sinha ◽  
Praveen P. Singh

Visible light organophotoredox catalysis has emerged as an invaluable tool for organic synthetic transformations since it works brilliantly in tandem with organic substrates and has been known to create unique chemical environment for organic transformations. Dicyanopyrazine (DPZ), a relatively lesser researched organophotoredox catalyst, has shown great potential through its catalytic activity in organic synthesis and necessitates attention of synthetic community.


2018 ◽  
Vol 4 (5) ◽  
Author(s):  
Alexandra Pop ◽  
Cristian Silvestru ◽  
Anca Silvestru

Abstract This chapter emphasizes aspects related to the role of organochalcogen (Se, Te) compounds with single E‒O and/or double E=O (E=Se, Te) bonds in organic synthesis, as reagents, intermediates, or catalysts, and it gives a larger extent mainly to data reported in the field during the last ten years. For each of these two heavier chalcogens the material is structured according to the oxidation state of the chalcogen and, for the same oxidation state, in sections dedicated to a particular type of compounds. Functionalization or cyclization reactions in which the organochalcogen compounds take part as nucleophiles, electrophiles or radicals, employed in various synthetic transformations, are discussed and, where available, the mechanistic aspects are outlined. New chiral species and new strategies were developed during last years in order to increase the yield, the reaction rate and the stereoselectivity in specific organic transformations, i.e. addition, oxidation, elimination, cyclization or rearrangement reactions. A notably attention was devoted to easily accessible and environmental friendly catalysts, re-usable and “green” solvents, as well as waste-free procedures.


Author(s):  
David R. Veblen

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.


2008 ◽  
Author(s):  
Tarek Salama ◽  
Saad Elmorsya ◽  
Mohamed Ismaila

Author(s):  
Shukla PK ◽  
Singh MP ◽  
Patel R

Indole and its derivatives have engaged a unique place in the chemistry of nitrogen heterocyclic compounds. The recognition of the plant growthhormone, heteroauxin, the significant amino acids, tryptamine & tryptophan and anti-inflammatory drug, indomethacine are the imperativederivatives of indole which have added stimulus to this review work. Isatin (1H-indole-2,3-dione), an indole derivative of plant origin. Althoughit is a naturally occurring compound, but was synthesized by Erdmann and Laurent in 1840 before it was found in nature. Isatin is a versatileprecursor for many biologically active molecules and its diversified nature makes it a versatile substrate for further modifications. It is concernedin many pharmacological activities like anti-malarial, antiviral, anti-allergic, antimicrobial etc; isatin and its derivatives have been also found todemonstrate promising outcomes against various cancer cell lines. This review provides a brief overview on the recent advances and futureperspectives on chemistry and biological aspects of isatin and its derivatives reported in the recent past.


2020 ◽  
Vol 24 ◽  
Author(s):  
Ghodsi Mohammadi Ziarani ◽  
Shima Roshankar ◽  
Fatemeh Mohajer ◽  
Alireza Badiei

Abstract:: Mesoporous silica nanomaterials provide an extraordinary advantage for making new and superior heterogeneous catalysts because of their surface silanol groups. The functionalized mesoporous SBA-15, such as acidic, basic, BrÖnsted, lewis acid, and chiral catalysts, are used for a wide range of organic synthesis. The importance of the chiral ligands, which were immobilized on the SBA-15, was mentioned in this review to achieve chiral products as valuable target molecules. Herein, their synthesis and application in different organic transformations are reviewed from 2016 till date 2020.


2015 ◽  
Vol 19 (9) ◽  
pp. 790-812 ◽  
Author(s):  
Bhaskara Nand ◽  
Garima Khanna ◽  
Ankita Chaudhary ◽  
Anshika Lumb ◽  
Jitender M. Khurana

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