Synthesis of biologically active molecules (whether at laboratory or industrial scale) remains a highly appealing area of modern organic chemistry. Nowadays, the need to access original bioactive scaffolds goes together with the desire to improve synthetic efficiency, while reducing the environmental footprint of chemical activities. Long neglected in the field of total synthesis, enantioselective organocatalysis has recently emerged as an environmentally friendly and indispensable tool for the construction of relevant bioactive molecules. Notably, enantioselective Bronsted acid catalysis has offered new opportunities in terms of both retrosynthetic disconnections and controlling stereoselectivity. The present report attempts to provide an overview of enantioselective total or formal syntheses designed around Bronsted acid-catalyzed transformations. To demonstrate the versatility of the reactions promoted and the diversity of the accessible motifs, this Minireview draws a systematic parallel between methods and retrosynthetic analysis. The manuscript is organized according to the main reaction types and the nature of newly-formed bonds.

Enantioselective Brønsted Acid Catalysis as a Tool for the Synthesis of Natural Products and Pharmaceuticals

This review summarizes the trends in the formation of complex or not so complex heterocyclic structures through 1,3-dipolar cy­cloadditions of azomethine ylides. Diastereo- and enantioselective processes as well as non-asymmetric cycloadditions constitute very important synthetic tools for achieving these compounds. This review covers the literature from 2015 through 2016 and organizes the research in terms of biologically important heterocycles and natural products from cascade 1,3-dipolar cycloadditions of azomethine ylides to the simpler forms of 1,3-dipolar cycloaddition. 1	Introduction 2 	Synthesis of Spirooxindoles 3 	Synthesis of Spiropyrrolidines 4 	Synthesis of Spiropiperidines and Piperidines 5 	Synthesis of Pyrrolidines and Fused Pyrrolidines 6 	Synthesis of Pyrrolizidines and Indolizidines 7 	Synthesis of Quinolone and Isoquinolines 8 	Conclusions

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Current Trends towards the Synthesis of Bioactive Heterocycles and Natural Products Using 1,3-Dipolar Cycloadditions (1,3-DC) with Azomethine Ylides

The asymmetric conjugate addition of carbon and heteroatom nucleophiles to nitroalkenes is a very interesting tool for the construction of highly functionalized synthetic building blocks Thanks to the rapid development of asymmetric organocatalysis, significant progress has been made during the last years in achieving efficiently this process, concerning chiral organocatalysts, substrates and reaction conditions This review surveys the advances in asymmetric organocatalytic conjugate addition reactions to α,β-unsaturated nitroalkenes developed between 2013 and early 2017

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Recent Advances in Asymmetric Organocatalyzed Conjugate Additions to Nitroalkenes

The synthesis of diastereo- and enantiopure heterocyclic molecules via catalytic asymmetric 1,3-dipolar cycloaddition reaction between azomethine ylides, generated in situ from α-amino acid-derived iminoesters and dipolarophiles is considered one of the most powerful and versatile techniques. In this review, we make a detailed overview of the latest developments in this area since 2014 and highlight the recent improvements in the structural scope of dipolarophiles, azomethine ylide precursors, and chiral ligands.

Recent advances in the enantioselective 1,3-dipolar cycloaddition of azomethine ylides and dipolarophiles

The prevalence of nitrogen containing heterocycles in natural products and pharmaceuticals is a doubtless fact. In this review, recent applications of a stereoselective aza-Michael reaction as an efficient tool for the asymmetric synthesis of naturally occurring nitrogen-containing heterocyclic scaffolds and their usefulness to pharmacology are reviewed and summarized. The available data are for the first time classified according to types of heterocyclic products and subdivided in accordance with synthetic methodologies used as key stereocontrolling steps (diastereoselective or enantioselective reactions, single bond-forming or cascade reactions, etc.). This classification is convenient for organic chemists and for researchers working in the areas of natural product synthesis and medicinal chemistry. Specific attention is paid to organocatalytic asymmetric versions of the aza-Michael reaction developed over the past decade.

Recent advances in the asymmetric synthesis of pharmacology-relevant nitrogen heterocycles via stereoselective aza-Michael reactions.

Organocatalytic domino/cascade reactions provide a convenient method for the construction of highly functionalized cyclic molecular structures bearing multiple stereocenters in a highly stereoselective fashion. A wide range of organocatalysts used for the construction of these architecturally complex molecules are reported. A distinct activation mode of monofunctional and bifunctional catalysts with different additive and bases used for synergistic co-operative activation also presented. The strategies and catalyst system described here highlight recent advances in the enantioselective synthesis of poly functionalized cyclic molecules via organocascade (Michael–Michael) reactions. This review focuses on the enantioselective synthesis of cyclic molecules via organocascade reactions and is organized on the basis of four categories of activation such as enamine–iminium catalysis, iminium–enamine catalysis, base–base catalysis and acid–base catalysis (bifunctional catalysis).

Current advances of organocatalytic Michael–Michael cascade reaction in the synthesis of highly functionalized cyclic molecules

Navigating the Synthesis of Quinoline Hybrid Molecules as Promising Anticancer Agents

Microwave‐Assisted Rapid and Efficient Synthesis of New Series of Chromene‐Based 1,2,4‐Oxadiazole Derivatives and Evaluation of Antibacterial Activity with Molecular Docking Investigation

Microwave‐assisted rapid and efficient synthesis of chromene‐fused pyrrole derivatives through multicomponent reaction and evaluation of antibacterial activity with molecular docking investigation

This review summarizes wonderful achievements in the field of the organocatalytic enantioselective Michael addition reaction involving nucleophilic attack of nitro alkane, malonates, cyanoacetates, hydroxyamines, malononitrile, thiols, cyanomethylphosphate, butenolide, coumarin, and 1-fluoro-1-nitro (phenylsulfonyl) methane to chalcones. A large number of efficient organocatalytic systems have been used to generate chiral Michael adducts with high enatioselectivity with excellent yield.

Pravati Panda

Papers

Current advances of organocatalytic Michael–Michael cascade reaction in the synthesis of highly functionalized cyclic molecules

Navigating the Synthesis of Quinoline Hybrid Molecules as Promising Anticancer Agents

Microwave‐Assisted Rapid and Efficient Synthesis of New Series of Chromene‐Based 1,2,4‐Oxadiazole Derivatives and Evaluation of Antibacterial Activity with Molecular Docking Investigation

Microwave‐assisted rapid and efficient synthesis of chromene‐fused pyrrole derivatives through multicomponent reaction and evaluation of antibacterial activity with molecular docking investigation

Recent advances of organocatalytic enantioselective Michael-addition to chalcone