N-Propargylic β-enaminocarbonyls: powerful and versatile building blocks in organic synthesis

α,β-Unsaturated γ-hydroxy-γ-butyrolactams are of a great interest due to their presence in designed pharmaceutical molecules and numerous natural products displaying a broad spectrum of biological activities. In addition, these five-membered heterocyclic compounds are also relevant and versatile building blocks in organic synthesis. In this context, strategies for the construction of these scaffolds has triggered considerable attention and this review highlights the progress in the formation of α,β-unsaturated γ-hydroxy-γ-butyrolactams (5-hydroxy-1,5-dihydro-2H-pyrrol-2-ones).1 Introduction2 Intramolecular Routes3 Intermolecular Routes4 Oxidation of Heterocyclic Compounds5 Miscellaneous6 Conclusion

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Applications of 3-Substituted 2-Alkoxy- and 2-Alkylthiopropenals in Organic Synthesis

Mini-Reviews in Organic Chemistry ◽

10.2174/1570193x18666210422121054 ◽

2021 ◽

Vol 18 ◽

Author(s):

Nadezhda V. Vchislo ◽

Ekaterina A. Verochkina

Keyword(s):

Natural Products ◽

Electron Density ◽

Organic Synthesis ◽

Heterocyclic Compounds ◽

Building Blocks ◽

The Real ◽

Broad Applicability ◽

Unsaturated Aldehydes

: α-Functionally substituted α,β-unsaturated aldehydes belong to the highly reactive class of compounds. They are used as versatile building blocks in organic synthesis. Due to the presence of several reactive sites in their structure, α,β-unsaturated aldehydes are widely employed as precursors of various acyclic and heterocyclic compounds, as well as complex natural products. At the same time, the acrylic systems with heteroatomic substituents (OAlk, SAlk) in the α-position are poorly studied. Therefore, it is impossible to reliably establish the distribution of electron density and to evaluate the real reactivity of each new representative of this class of compounds. This minireview summarizes the works demonstrating the broad applicability of 3-substituted 2-alkoxy and 2-alkylthiopropenals in organic synthesis.

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Recent Advances in Organocatalyzed Asymmetric Synthesis of Benzopyran and Benzodihydropyran (Chromane) Nuclei

Symmetry ◽

10.3390/sym11121510 ◽

2019 ◽

Vol 11 (12) ◽

pp. 1510

Author(s):

Renato Dalpozzo ◽

Raffaella Mancuso

Keyword(s):

Natural Products ◽

Asymmetric Synthesis ◽

Organic Synthesis ◽

Building Blocks ◽

Core Structure ◽

The Core ◽

Recent Advances ◽

Set Up

Benzopyran and benzodihydropyran (chromane) nuclei are the core structure of many natural products, in particular flavonoids. Many compounds possessing this structure are nutraceuticals, pharmaceutical nutrients. Therefore, benzopyran and chromane scaffolds are important building blocks in organic synthesis and many efforts have been made to set up efficient methods for their synthesis. In particular, asymmetric methods are of great importance, being natural products, and generally chiral substances. This review aims to cover literature in the range 2017–first half of 2019.

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Tetralone scaffolds and their potential therapeutic applications

Letters in Drug Design & Discovery ◽

10.2174/1570180817999201013165656 ◽

2020 ◽

Vol 17 ◽

Author(s):

Bhagwati Gauni ◽

Krunal Mehariya ◽

Anamik Shah ◽

Srinivas Murty Duggirala

Keyword(s):

Antitumor Activity ◽

Organic Synthesis ◽

Small Molecule ◽

Heterocyclic Compounds ◽

Biological Activities ◽

Acetylcholinesterase Inhibitors ◽

Building Blocks ◽

Structural Features ◽

Therapeutic Applications ◽

Small Molecule Library

: Substituted tetralones have played a substantial role in organic synthesis due to their strong reactivity and suitability as a starting material for a range of synthetic heterocyclic compounds, pharmaceuticals along with biological activities as well as precursors of many natural products and their derivatives. Many α-tetralone derivatives are building blocks, that have been used in the synthesis of therapeutically functional compounds like some antibiotics, antidepressants, acetylcholinesterase inhibitors effective for treating Alzheimer’s disease and alkaloids possessing antitumor activity. In this review, there has been an attempt to explore the small molecule library having α-tetralone scaffold along with their diverse biological activities. Structural features of α-tetralone derivatives responsible for potential therapeutic applications are also described.

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Regioselective N-alkylation of (2-chloroquinolin-3-yl) methanol with N-heterocyclic compounds using the Mitsunobu reagent

Chemical Papers ◽

10.2478/s11696-011-0018-1 ◽

2011 ◽

Vol 65 (3) ◽

Cited By ~ 3

Author(s):

Selvaraj Roopan ◽

Fazlur-Rahman Khan ◽

Jong Jin

Keyword(s):

Natural Product ◽

Organic Synthesis ◽

Heterocyclic Compounds ◽

Building Blocks ◽

Natural Product Synthesis ◽

Mitsunobu Reaction ◽

Reaction Conditions ◽

Diethyl Azodicarboxylate ◽

Nitrogen Heterocyclic

AbstractThe Mitsunobu reaction is a well-established fundamental reaction and has been widely applied in organic synthesis. In this paper, under Mitsunobu conditions dehydration proceeds between (2-chloroquinolin-3-yl)methanol and nitrogen heterocyclic compounds such as quinazolinone, pyrimidone, 2-oxoquinoline in dry THF in the presence of triethylamine, triphenylphosphane and diethyl azodicarboxylate to give the corresponding products. As part of our recent research, we attempted to couple two N-heterocyclic compounds under Mitsunobu reaction conditions to provide efficient building blocks for natural product synthesis.

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Isoxazol-5-ones as Strategic Building Blocks in Organic Synthesis

Synthesis ◽

10.1055/s-0036-1589534 ◽

2018 ◽

Vol 50 (13) ◽

pp. 2473-2489 ◽

Cited By ~ 9

Author(s):

Amanda da Silva ◽

Alessandra Fernandes ◽

Samuel Thurow ◽

Mateus Stivanin ◽

Igor Jurberg

Keyword(s):

Natural Products ◽

Biological Activity ◽

Organic Synthesis ◽

Building Block ◽

Building Blocks ◽

Short Review ◽

Preparation Methods ◽

Drug Candidates ◽

General Aspects

Isoxazol-5-one rings have been identified as relevant motifs in drug candidates, agrochemicals, and materials. Furthermore, this heterocycle has been also applied as a versatile building block for the preparation of a variety of densely functionalized molecules. This short review will present the most representative applications of isoxazol-5-ones in organic synthesis while discussing their properties and reactivity.1 Introduction1.1 General Aspects1.1.1 Tautomerism1.1.2 Importance: Natural Products Isolation, Biological Activity, and Materials1.1.3 Preparation Methods2 Isoxazol-5-ones in Organic Synthesis2.1 General Reactivity2.2 Specific Examples2.2.1 Alkylation Strategies2.2.2 Alkyne Synthesis2.2.3 Annulation Reactions2.2.4 N–O Bond Insertions2.2.4.1 Preparation of 1,3-Oxazin-6-ones3 Conclusions

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Catalytic Asymmetric Osmium-Free Dihydroxylation of Alkenes

Synthesis ◽

10.1055/a-1325-4092 ◽

2020 ◽

Author(s):

Chuan Wang ◽

Shixia Su

Keyword(s):

Natural Products ◽

Organic Synthesis ◽

Phase Transfer ◽

Building Blocks ◽

Short Review ◽

Optically Active ◽

Asymmetric Dihydroxylation ◽

A Subunit ◽

Vicinal Diols ◽

Catalytic Asymmetric

AbstractAsymmetric dihydroxylation of alkenes is one of the cornerstone reactions in organic synthesis, providing a direct entry to optically active vicinal diols, which are not only a subunit in natural products but also versatile building blocks. In recent years, considerable progress in catalytic asymmetric osmium-free dihydroxylation has been achieved. This short review presents a concise summary of the reported methods of catalytic asymmetric osmium-free dihydroxylation.1 Introduction2 Iron-Catalyzed Asymmetric syn-Dihydroxylation of Alkenes3 Manganese-Catalyzed Asymmetric syn-Dihydroxylation of Alkenes4 Palladium/Gold Bimetallic Nanocluster-Catalyzed Asymmetric syn-Dihydroxylation of Alkenes5 Enzyme-Catalyzed Asymmetric anti-Dihydroxylation of Alkenes6 Amine-Catalyzed Asymmetric Formal anti-Dihydroxylation of Enals7 Diselenide-Catalyzed anti-Dihydroxylation of Alkenes8 Molybdenum-Catalyzed Asymmetric anti-Dihydroxylation of Allylic Alcohols9 Phase-Transfer-Catalyzed Asymmetric Dihydroxylation of α-Aryl Acrylates10 Conclusion

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Recent Advance on Benzofuranones: Synthesis and Transformation via C-H Functionalization

Synthesis ◽

10.1055/a-1405-5761 ◽

2021 ◽

Author(s):

Zhi Tang ◽

Zhou Tong ◽

Shuang-Feng Yin ◽

Nobuaki Kambe ◽

Renhua Qiu

Keyword(s):

Natural Products ◽

Transition Metal ◽

Organic Synthesis ◽

Building Blocks ◽

Efficient Synthesis ◽

Bond Functionalization ◽

Pka Value ◽

Transition Metal Catalyzed ◽

Metal Catalyzed

Benzofuranone is a sort of important skeleton in many fields, such as natural products, pharmaceuticals, building blocks, antioxidants and dyes. Their efficient synthesis and transformations have attracted great attentions in organic synthesis. They can be synthesized by Friedel−Crafts reaction, intramolecular dehydration ring-closing reaction and transition-metal-catalyzed reaction, etc. And their direct utilization to prepare other functional molecules enhances their further application. Due to their low pKa value and easy enolization ability, the transformation of benzofuranones via C(3)-H bond functionalization is a hot issue in the last ten years. Herein, we highlight the advances on the synthesis of benzofuranones and its transformation via C-H functionalization. Some of other transformations related to benzofuranones are also referred in this review.

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The Rearrangement of Alkylallenes to 1,3-Dienes

Reactions ◽

10.3390/reactions3010006 ◽

2022 ◽

Vol 3 (1) ◽

pp. 70-86

Author(s):

Yassir Al-Jawaheri ◽

Marc Colin Kimber

Keyword(s):

Natural Products ◽

Transition Metal ◽

Organic Synthesis ◽

Building Blocks ◽

Drug Candidate ◽

Synthetic Route ◽

Skeletal Rearrangement ◽

Synthetic Transformations

1,3-Dienes are vital building blocks in organic synthesis. They underpin many fundamental synthetic transformations and are present in numerous natural products and drug candidate molecules. The rearrangement of an alkylallene to a 1,3-diene is an atom efficient, redox neutral, transformation that provides a straightforward synthetic route to functionalized 1,3-dienes. Herein, we provide an account of this transformation using allenes that are not predisposed by the presence of heteroatoms or electron-withdrawing groups directly attached to the allene. Early reports of this skeletal rearrangement are acid-mediated approaches, with limited substrate scope, but they provide valuable mechanistic insights. More recent transition metal-mediated approaches that exhibit improved substrate scope are described, together with isolated examples that have utilized this rearrangement.

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Photo-induced copper-catalyzed sequential 1,n-HAT enabling the formation of cyclobutanols

Nature Communications ◽

10.1038/s41467-021-26670-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Zhusong Cao ◽

Jianye Li ◽

Guozhu Zhang

Keyword(s):

Natural Products ◽

Hydrogen Atom ◽

Functional Groups ◽

Organic Synthesis ◽

Copper Complex ◽

Building Blocks ◽

Hydrogen Atom Transfer ◽

Efficient Synthesis ◽

Bond Functionalization ◽

Cascade Cyclization

AbstractCyclobutanols are privileged cyclic skeletons in natural products and synthetic building blocks. C(sp3)−H functionalization is a prolonged challenge in organic synthesis. The synthesis of cyclobutanols through double C(sp3)-H bond functionalization remains elusive. Here we report the efficient synthesis of cyclobutanols through intermolecular radical [3 + 1] cascade cyclization, involving the functionalization of two C − H bonds through sequential hydrogen atom transfer. The copper complex reduces the iodomethylsilyl alcohols efficiently under blue-light irradiation to initiate the tandem transformation. The mild reaction tolerates a broad range of functional groups and allows for the facile generation of elaborate polycyclic structures.

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