scholarly journals Recent Developments on 1,3-Dipolar Cycloaddition Reactions by Catalysis in Green Solvents

Catalysts ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 65 ◽  
Author(s):  
Loredana Maiuolo ◽  
Vincenzo Algieri ◽  
Fabrizio Olivito ◽  
Antonio De Nino
Keyword(s):  
Ionic Liquids ◽  
Heterocyclic Compounds ◽  
Deep Eutectic Solvents ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Important Class ◽  
Green Solvents ◽  
Dipolar Cycloadditions ◽  
Recent Developments ◽  
Selection Of

The use of eco-compatible synthetic procedures in organic reactions and, in particular, in 1,3-dipolar cycloaddition reactions, has recently received a great deal of attention and considerable progress has been achieved in this area in the last years. This review summarizes the approaches currently employed to synthesize heterocyclic compounds by catalyzed 1,3-dipolar cycloadditions in green solvents in the last six years. Our choice to do a selection of the literature from 2014 to 2019 was made considering the absence of a recent review about this period, to our knowledge. Several examples to construct heterocycles by 1,3-dipolar cycloadditions will be discussed in this work subdivided in function of the most important class of non-conventional and green solvents, i.e., ionic liquids (ILs), deep eutectic solvents (DES), and water.

1,3-Dipolar Cycloadditions Involving Allenes: Synthesis of Five-Membered Rings

2020 ◽  
Vol 23 (27) ◽  
pp. 3064-3134 ◽  
Author(s):  
Ana L. Cardoso ◽  
Maria I.L. Soares
Keyword(s):  
Transition Metal ◽  
Cycloaddition Reaction ◽  
Building Blocks ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Relevant Research ◽  
Dipolar Cycloadditions ◽  
Recent Developments ◽  
Synthetic Equivalent ◽  
Metal Catalyzed

The 1,3-dipolar cycloaddition reaction is a powerful and versatile strategy for the synthesis of carbocyclic and heterocyclic five-membered rings. Herein, the most recent developments on the [3+2] cycloaddition reactions using allenes acting either as dipolarophiles or 1,3-dipole precursors, are highlighted. The recent contributions on the phosphine- and transition metal-catalyzed [3+2] annulations involving allenes as substrates are also covered, with the exception of those in which the formation of a 1,3-dipole (or synthetic equivalent) is not invoked. This review summarizes the most relevant research in which allenes are used as building blocks for the construction of structurally diverse five-membered rings via [3+2] annulation reactions.

scholarly journals Recent advances in the electrochemical construction of heterocycles

2014 ◽  
Vol 10 ◽  
pp. 2858-2873 ◽  
Author(s):  
Robert Francke
Keyword(s):  
Heterocyclic Compounds ◽  
Elevated Temperatures ◽  
Ring Formation ◽  
Environmentally Benign ◽  
Heterocyclic Chemistry ◽  
Ambient Conditions ◽  
Recent Developments ◽  
Strong Acids ◽  
Selection Of ◽  
Made In

Due to the fact that the major portion of pharmaceuticals and agrochemicals contains heterocyclic units and since the overall number of commercially used heterocyclic compounds is steadily growing, heterocyclic chemistry remains in the focus of the synthetic community. Enormous efforts have been made in the last decades in order to render the production of such compounds more selective and efficient. However, most of the conventional methods for the construction of heterocyclic cores still involve the use of strong acids or bases, the operation at elevated temperatures and/or the use of expensive catalysts and reagents. In this regard, electrosynthesis can provide a milder and more environmentally benign alternative. In fact, numerous examples for the electrochemical construction of heterocycles have been reported in recent years. These cases demonstrate that ring formation can be achieved efficiently under ambient conditions without the use of additional reagents. In order to account for the recent developments in this field, a selection of representative reactions is presented and discussed in this review.

1,3-Dipolar Cycloadditions of a Chiral Oxazolidinone With Nitrones and Nitrile Oxides

1995 ◽  
Vol 48 (9) ◽  
pp. 1511 ◽  
Author(s):  
SG Pyne ◽  
J Safaei-G ◽  
BW Skelton ◽  
AH White
Keyword(s):  
Single Crystal ◽  
Hydrogen Atmosphere ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
The Novel ◽  
X Ray ◽  
Dipolar Cycloadditions ◽  
Nitrile Oxides ◽  
Exocyclic Methylene

The 1,3-dipolar cycloaddition reactions of the chiral oxazolidinone (1) and nitrones are highly regioselective and only 5,5-disubstituted isoxazolidine adducts are formed. These reactions occur under equilibrating conditions to give the more stable adducts that result from addition to the exocyclic methylene of (1) from the sterically more hindered π-face. The endo adducts are generally thermodynamically favoured. In one case the novel azetidine (21) was formed from the treatment of the adduct (4a) with palladium hydroxide on carbon under a hydrogen atmosphere. The major adducts from the reaction of (1) and nitrile oxides (16a,b) had the expected stereochemistry, addition of the 1,3-dipole having occurred from the less hindered π-face of the exocyclic methylene of (1). The stereochemistry of many of these products has been elucidated by single-crystal X-ray structural determinations.

scholarly journals Recent Progress of Cu-Catalyzed Azide-Alkyne Cycloaddition Reactions (CuAAC) in Sustainable Solvents: Glycerol, Deep Eutectic Solvents, and Aqueous Media

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2015 ◽  
Author(s):  
Noel Nebra ◽  
Joaquín García-Álvarez
Keyword(s):  
Recent Progress ◽  
Copper Catalyst ◽  
Aqueous Media ◽  
Deep Eutectic Solvents ◽  
Dipolar Cycloaddition ◽  
Green Solvents ◽  
Sustainable Solvents ◽  
Volatile Organic ◽  
Water Glycerol ◽  
Reaction Media

This mini-review presents a general overview of the progress achieved during the last decade on the amalgamation of CuAAC processes (copper-catalyzed azide-alkyne cycloaddition) with the employment of sustainable solvents as reaction media. In most of the presented examples, the use of water, glycerol (Gly), or deep eutectic solvents (DESs) as non-conventional reaction media allowed not only to recycle the catalytic system (thus reducing the amount of the copper catalyst needed per mole of substrate), but also to achieve higher conversions and selectivities when compared with the reaction promoted in hazardous and volatile organic solvents (VOCs). Moreover, the use of the aforementioned green solvents also permits the improvement of the overall sustainability of the Cu-catalyzed 1,3-dipolar cycloaddition process, thus fulfilling several important principles of green chemistry.

scholarly journals Huisgen [3 + 2] Dipolar Cycloadditions of Phthalazinium Ylides to Activated Symmetric and Non-Symmetric Alkynes

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4416
Author(s):  
Vasilichia Antoci ◽  
Costel Moldoveanu ◽  
Ramona Danac ◽  
Violeta Mangalagiu ◽  
Gheorghita Zbancioc
Keyword(s):  
Reaction Time ◽  
Comparative Study ◽  
Cycloaddition Reaction ◽  
Environmentally Friendly ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Dimethyl Acetylenedicarboxylate ◽  
Thermal Heating ◽  
Dipolar Cycloadditions ◽  
Methyl Propiolate

We present herein a straightforward and efficient pathway for the synthesis of pyrrolophthalazine cycloadducts via Huisgen [3 + 2] dipolar cycloaddition reactions of phthalazinium ylides to methyl propiolate or dimethyl acetylenedicarboxylate (DMAD). A thoroughly comparative study concerning the efficiency of synthesis, conventional thermal heating (TH) versus microwave (MW) and ultrasound (US) irradiation, has been performed. The cycloaddition reactions of phthalazinium ylides to methyl propiolate occur regiospecific, with a single regioisomer being obtained. Under conventional TH, the cycloaddition reaction of phthalazinium ylides with DMAD occurs to a mixture of inseparable partial and fully aromatized pyrrolophthalazine cycloadducts, while MW or US irradiation are leading only to fully aromatized compounds, with the reactions becoming selective. A feasible mechanism for formation of fully aromatized compounds is presented. Besides selectivity, it has to be noticed that the reaction setup under MW or US irradiation offer a number of other certain advantages: higher yields, decreasing of the amount of used solvent comparative with TH, decreasing of the reaction time from hours to minutes and decreasing of the consumed energy; consequently, these reactions could be considered environmentally friendly.

1,3-Dipolar cycloadditions of nitrile oxides with 7-oxa- and 7-azabenzonorbornadienes

2014 ◽  
Vol 92 (7) ◽  
pp. 635-639 ◽  
Author(s):  
Jaipal R. Nagireddy ◽  
Emily Carlson ◽  
William Tam
Keyword(s):  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions ◽  
Biological Testing ◽  
Dipolar Cycloadditions ◽  
Nitrile Oxides ◽  
Anti Cancer ◽  
Efficient Construction ◽  
Cancer Activity

Dipolar cycloaddition reactions allow for the efficient construction of five-membered heterocycles, often with diverse medicinal applications. We examined the 1,3-dipolar cycloaddition of 7-oxabenzonorbornadienes and 7-azabenzonorbornadienes with acetonitrile oxide and benzonitrile oxide, achieving an assortment of heterobicycle-fused isoxazolines with good to excellent yields. All isoxazolines were consistently directed to the exo face of the bicyclic framework with complete stereoselectivity. Preliminary biological testing of the adducts also showed positive anti-cancer activity, suggesting their potential pharmaceutical utility.

Investigation of 1,3-Dipolar Cycloaddition Reactions of Unsaturated Nitrones in Ionic Liquids

2006 ◽  
Vol 25 (8) ◽  
pp. 867-870 ◽  
Author(s):  
M. Hornyák ◽  
Z. Kele ◽  
L. Kovács ◽  
P. Forgó ◽  
N. M. Howarth
Keyword(s):  
Ionic Liquids ◽  
Dipolar Cycloaddition ◽  
Cycloaddition Reactions
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