Organocatalytic Synthesis of Heterocycles: A Brief Overview Covering Recent Aspects

2020 ◽  
Vol 07 ◽  
Author(s):  
Rajib Sarkar ◽  
Chhanda Mukhopadhyay
Keyword(s):  
Organic Synthesis ◽  
Organic Molecules ◽  
Synthetic Methods ◽  
Environmentally Benign ◽  
Reaction Conditions ◽  
Small Organic Molecules ◽  
Heterocycle Synthesis ◽  
The Past ◽  
Metal Catalyzed ◽  
Atom Bond

Abstract:: The use of small organic molecules as organocatalysts in organic synthesis has intensely studied over the past decade. In this emerging field, considerable study has led to the introduction of various efficient organocatalyzed synthetic methods of carbon-carbon and carbon-hetero atom bond formations. The use of these organocatalysts also emerged environmentally benign reaction conditions compared to the metal catalyzed transformations. In this review, we make a special attention on the most recent organocatalytic protocols reported for the synthesis of heterocycles. The works have been outlined by depending on the organocatalysts used as (i) nitrogen based molecules as organocatalyst, (ii) NHCs as organocatalyst, and (iii) phosphorus based molecules as organocatalyst. The discussion intends to reveal the scope as well as vitality of organocatalysis in the area of heterocycle synthesis.

Metal and Non-Metal Catalysts in the Synthesis of Five-Membered S-Heterocycles

2019 ◽  
Vol 16 (2) ◽  
pp. 258-275 ◽  
Author(s):  
Navjeet Kaur
Keyword(s):  
Organic Synthesis ◽  
Biological Activities ◽  
Reaction Times ◽  
Research Field ◽  
Environmentally Benign ◽  
Metal Catalyst ◽  
Efficient Synthesis ◽  
Heterocyclic Molecules ◽  
The Past ◽  
Harsh Conditions

Background:A wide variety of biological activities are exhibited by N, O and S containing heterocycles and recently, many reports appeared for the synthesis of these heterocycles. The synthesis of heterocycles with the help of metal and non-metal catalyst has become a highly rewarding and important method in organic synthesis. This review article concentrated on the synthesis of S-heterocylces in the presence of metal and non-metal catalyst. The synthesis of five-membered S-heterocycles is described here.Objective:There is a need for the development of rapid, efficient and versatile strategy for the synthesis of heterocyclic rings. Metal, non-metal and organocatalysis involving methods have gained prominence because traditional conditions have disadvantages such as long reaction times, harsh conditions and limited substrate scope.Conclusion:The metal-, non-metal-, and organocatalyst assisted organic synthesis is a highly dynamic research field. For ßthe chemoselective and efficient synthesis of heterocyclic molecules, this protocol has emerged as a powerful route. Various methodologies in the past few years have been pointed out to pursue more sustainable, efficient and environmentally benign procedures and products. Among these processes, the development of new protocols (catalysis), which avoided the use of toxic reagents, are the focus of intense research.

Advance synthetic approaches to 1,2,3-triazole derived compounds: State of art 2004-2020

2021 ◽  
Vol 08 ◽  
Author(s):  
Adarsh Sahu
Keyword(s):  
Structural Characteristics ◽  
Cycloaddition Reaction ◽  
Reaction Times ◽  
Synthetic Methods ◽  
Environmentally Benign ◽  
Future Directions ◽  
Triazole Derivatives ◽  
The Past ◽  
Synthetic Approaches ◽  
Reaction Profile

Background: 1,2,3-triazole is considered widely explored scaffolds by medicinal chemists because of their therapeutic importance. The structural characteristics of 1,2,3-triazoles allow this to mimic certain functional groups demonstrating its utility to prepare new medicinal compounds using the concept of bioisosterism and molecular hybridization. Centered on Huisgens cycloaddition reaction, over the past decade and a half, click chemistry approaches were developed to furnish triazole derivatives with various applications ranging from drugs to bioconjugation linkers. Objective: In the present review, we aim to highlight the different approaches developed for the synthesis of 1,2,3-triazole derivatives and in particular advances in synthetic methods for the last 16 years. This review is also intended to help researchers for finding potential future directions and scope in the development of synthetic strategies. Conclucion: As summarized through the compilation of recent advances for 1,2,3-triazole synthesis, it is clear that these protocols have numerous advantages such as cleaner reaction profile, shorter reaction times, excellent product yields, environmentally benign milder reactions, and safe operations.

scholarly journals Advances in the Preparation of Fluorinated Isoquinolines: A Decade of Progress

2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Joseph C. Sloop
Keyword(s):  
Transition Metal ◽  
Functional Groups ◽  
Synthetic Methods ◽  
Ring Systems ◽  
Heterocyclic Molecules ◽  
The Past ◽  
Ring Assembly ◽  
Metal Catalyzed ◽  
Synthetic Approaches ◽  
Isoquinoline Derivatives

Heterocyclic molecules incorporating fluorinated isoquinoline components are found in many medicinally and agriculturally important bioactive products as well as industrially impactful materials. Within the past decade, a variety of isoquinolinic ring assembly techniques has enabled the introduction of diverse fluorine-containing functionalities which can enhance potential bioactivity and industrial utility. This review examines recent noncatalyzed and transition metal catalyzed synthetic approaches to the assembly of isoquinoline derivatives that are ring-fluorinated and/or result in the incorporation of fluorine-containing functional groups. Specifically, efficient synthetic methods and regioselectivity in the incorporation of functional groups into isoquinoline ring systems are examined.

scholarly journals Aldehydes as powerful initiators for photochemical transformations

2020 ◽  
Vol 16 ◽  
pp. 833-857 ◽  
Author(s):  
Maria A Theodoropoulou ◽  
Nikolaos F Nikitas ◽  
Christoforos G Kokotos
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Organic Molecules ◽  
Photophysical Properties ◽  
Organic Transformations ◽  
Aliphatic Aldehydes ◽  
Small Organic Molecules ◽  
Photochemical Transformations ◽  
The Way

Photochemistry, the use of light to promote organic transformations, has been known for more than a century but only recently has revolutionized the way modern chemists are thinking. Except from transition metal-based complexes, small organic molecules have been introduced as catalysts or initiators. In this review, we summarize the potential that (aromatic or aliphatic) aldehydes have as photoinitiators. The photophysical properties and photoreactivity of benzaldehyde are initially provided, followed by applications of aldehydes as initiators for polymerization reactions. Finally, the applications to date regarding aldehydes as photoinitiators in organic synthesis are presented.

Anodic Oxidation as an Enabling Tool for the Synthesis of Natural Products

Synthesis ◽  
2020 ◽  
Vol 52 (19) ◽  
pp. 2781-2794
Author(s):  
Till Opatz ◽  
Leander Geske ◽  
Eisuke Sato
Keyword(s):  
Organic Synthesis ◽  
Large Scale ◽  
Bond Formation ◽  
Short Review ◽  
Natural Product Synthesis ◽  
Environmentally Benign ◽  
Full Potential ◽  
Future Prospects ◽  
Reaction Conditions ◽  
Chemical Oxidants

Electrochemistry provides a valuable toolbox for organic synthesis and offers an appealing, environmentally benign alternative to the use of stoichiometric quantities of chemical oxidants or reductants. Its potential to control current efficiency along with providing alternative reaction conditions in a classical sense makes electrochemistry a suitable method for large-scale industrial transformations as well as for laboratory applications in the synthesis of complex molecular architectures. Even though research in this field has intensified over the recent decades, many synthetic chemists still hesitate to add electroorganic reactions to their standard repertoire, and hence, the full potential of preparative organic electrochemistry has not yet been unleashed. This short review highlights the versatility of anodic transformations by summarizing their application in natural product synthesis.1 Introduction2 Shono-Type Oxidation3 C–N/N–N Bond Formation4 Aryl–Alkene/Aryl–Aryl Coupling5 Cycloadditions Triggered by Oxidation of Electron-Rich Arenes6 Spirocycles7 Miscellaneous Transformations8 Future Prospects

scholarly journals Metal-catalyzed organic reactions by Resonant Acoustic Mixing

2021 ◽  
Author(s):  
Lori Gonnet ◽  
Cameron Lennox ◽  
Jean-Louis Do ◽  
Ivani Malvestiti ◽  
Stefan Koenig ◽  
...  
Keyword(s):  
Ball Milling ◽  
Organic Synthesis ◽  
Mechanochemical Synthesis ◽  
Catalytic Synthesis ◽  
Antidiabetic Drug ◽  
Ring Closing Metathesis ◽  
Reaction Conditions ◽  
Metal Catalyzed ◽  
Resonant Acoustic Mixing ◽  
Model Reactions

We introduce catalytic organic synthesis by Resonant Acoustic Mixing (RAM): a mechanochemical methodology that does not require bulk solvent or milling media. Using as model reactions ruthenium-catalyzed ring-closing metathesis, ene-yne metathesis and copper-catalyzed sulfonamide-isocyanate coupling, we demonstrate RAM-based mechanochemical synthesis that is faster and operationally simpler than conventional ball milling. Moreover, the method can be readily scaled-up, as demonstrated by straightforward catalytic synthesis of the antidiabetic drug Tolbutamide from hundreds of milligrams to at least 10 grams, without any significant changes in reaction conditions.

scholarly journals Redox reactions of small organic molecules using ball milling and piezoelectric materials

Science ◽  
2019 ◽  
Vol 366 (6472) ◽  
pp. 1500-1504 ◽  
Author(s):  
Koji Kubota ◽  
Yadong Pang ◽  
Akira Miura ◽  
Hajime Ito
Keyword(s):  
Ball Milling ◽  
Organic Molecules ◽  
Piezoelectric Materials ◽  
Mechanical Energy ◽  
Diazonium Salts ◽  
Small Organic Molecules ◽  
Bond Forming ◽  
Complementary Method ◽  
The Past ◽  
Redox Activation

Over the past decade, photoredox catalysis has harnessed light energy to accelerate bond-forming reactions. We postulated that a complementary method for the redox-activation of small organic molecules in response to applied mechanical energy could be developed through the piezoelectric effect. Here, we report that agitation of piezoelectric materials via ball milling reduces aryl diazonium salts. This mechanoredox system can be applied to arylation and borylation reactions under mechanochemical conditions.

scholarly journals C-H Functionalization via Iron-Catalyzed Carbene-Transfer Reactions

Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 880 ◽  
Author(s):  
Claire Empel ◽  
Sripati Jana ◽  
Rene M. Koenigs
Keyword(s):  
Functional Groups ◽  
Organic Molecules ◽  
Transfer Reactions ◽  
Iron Catalysts ◽  
Reaction Conditions ◽  
Carbene Complexes ◽  
Small Organic Molecules ◽  
Iron Heme ◽  
Over Time ◽  
Functionalization Reaction

The direct C-H functionalization reaction is one of the most efficient strategies by which to introduce new functional groups into small organic molecules. Over time, iron complexes have emerged as versatile catalysts for carbine-transfer reactions with diazoalkanes under mild and sustainable reaction conditions. In this review, we discuss the advances that have been made using iron catalysts to perform C-H functionalization reactions with diazoalkanes. We give an overview of early examples employing stoichiometric iron carbene complexes and continue with recent advances in the C-H functionalization of C(sp2)-H and C(sp3)-H bonds, concluding with the latest developments in enzymatic C-H functionalization reactions using iron-heme-containing enzymes.

Alkylation Reactions with Alkylsulfonium Salts

Synthesis ◽  
2021 ◽  
Author(s):  
Ze-Yu Tian ◽  
Yu Ma ◽  
Cheng-Pan Zhang
Keyword(s):  
Organic Molecules ◽  
High Efficiency ◽  
Building Blocks ◽  
Organometallic Reagents ◽  
The Past ◽  
Wide Range ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Alkylation Reactions

Application of alkylsulfonium salts as alkyl transfer reagents in organic synthesis has reemerged over the past years. Numerous heteroatom- and carbon-centered nucleophiles, alkenes, arenes, alkynes, organometallic reagents, and others were readily alkylated by alkylsulfonium salts under mild conditions. The reactions feature convenience, high efficiency, readily accessible and structurally diversified alkylation reagents, good functional group tolerance, and a wide range of substrate types, allowing for facile synthesis of various useful organic molecules from the commercially available building blocks. This review summarizes the alkylation reactions using either isolated or in situ formed alkylsulfonium salts via nucleophilic substitution, transition-metal-catalyzed reactions, and photoredox processes.

An Integrated Console for Capsule-Based, Fully Automated Organic Synthesis

2019 ◽  
Author(s):  
Tuo Jiang ◽  
Samuele Bordi ◽  
Angus E. McMillan ◽  
Kuang-Yen Chen ◽  
Fumito Saito ◽  
...  
Keyword(s):  
Artificial Intelligence ◽  
Operating System ◽  
Organic Synthesis ◽  
Reductive Amination ◽  
Organic Molecules ◽  
User Involvement ◽  
Synthetic Methods ◽  
Coupling Reactions ◽  
User Friendly ◽  
Complex Organic

The current laboratory-based practice of organic synthesis renders automation difficult, suffers from safety and environmental hazards, and hampers the implementation of artificial intelligence guided drug discovery. Using a combination of innovative reagent design, hardware engineering, and a simple operating system we provide an instrument capable of executing complex organic reactions with prepacked capsules in a fully automated fashion. The machine conducts coupling reactions and delivers the purified products with minimal user involvement. Two of the most desirable reaction classes – the synthesis of saturated N-heterocycles and reductive amination – were implemented, along with multi-step sequences that provide drug-like organic molecules in a fully automated manner. We envision that this system will serve as a console for developers to provide synthetic methods as integrated, user-friendly packages for conducting organic synthesis in a safe and convenient fashion.

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