Enantioselective organocatalytic syntheses of α-selenated α- and β-amino acid derivatives

Organic & Biomolecular Chemistry, Год журнала: 2022, Номер 20(4), С. 824 - 830

Опубликована: Янв. 1, 2022

Selenium-containing amino acids are valuable targets but methods for the stereoselective α-selenation of simple acid precursors rare. We herein report enantioselective electrophilic azlactones (masked α-amino derivatives) and isoxazolidin-5-ones β-amino acids) using Cinchona alkaloids as easily accessible organocatalysts. A variety differently substituted derivatives was accessed with reasonable levels enantioselectivities further studies concerning stability suitability these compounds manipulations have been carried out well.

Язык: Английский

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Recent Advances in Asymmetric [1,2]-Stevens-Type Rearrangement via Metal Carbenes

Synthesis, Год журнала: 2023, Номер 55(14), С. 2118 - 2127

Опубликована: Март 8, 2023

Abstract The [1,2]-Stevens rearrangement is a widely used transformation in synthetic organic chemistry. However, enantioselective versions are relatively limited and most of them rely on substrate-induced methodologies. In recent years, metal carbene chemistry has been extensively investigated, the related asymmetric experienced rapid development by employing ylide intermediates generated from reaction carbenes with heteroatoms. This review summarizes advances [1,2]-Stevens-type via presenting their product diversity, selectivity, mechanistic rationale, which organized based mode chirality control. 1 Introduction 2 Substrate-Induced Asymmetric [1,2]-Stevens-Type Rearrangement 3 Catalyst-Controlled 4 Conclusion Outlook

Язык: Английский

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Electrochemical Oxidative Difunctionalization of Diazo Compounds with Diselenides and Nucleophiles

Organic Letters, Год журнала: 2024, Номер 26(19), С. 4071 - 4076

Опубликована: Май 2, 2024

An electrochemical oxidative difunctionalization of diazo compounds with diselenides and nucleophiles has been developed. This innovative approach yields a diverse array selenium-containing pyrazole esters alkoxy esters, overcoming the limitations traditional synthesis methods. Remarkably, various nucleophiles, including acids, alcohols, pyrazoles, can be seamlessly incorporated. Notably, this protocol boasts high atom efficiency, excellent functional group tolerance, good efficiency operates under transition metal- oxidant-free conditions, distinguishing it in field.

Язык: Английский

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Rhodium-catalyzed selenylation and sulfenylation of quinoxalinones ‘on water’

RSC Advances, Год журнала: 2023, Номер 13(9), С. 6191 - 6198

Опубликована: Янв. 1, 2023

A rhodium-catalysed, regioselective synthetic methodology for selenylation and sulfenylation of 3-phenyl quinoxolinones has been developed through N-directed C-H activation in the presence silver triflimide, carbonate using dichalcogenides 'on water'. The proven to be efficient, green. Using this method, a range selenylations sulfenylations substrates carried out good excellent yields. Further, late-stage functionalisation produced potential anti-tumour, anti-fungal anti-bacterial agents making these compounds drug candidates.

Язык: Английский

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Recent Advances in Organic Reactions Using Water as Solvent

Опубликована: Март 8, 2024

In the past two decades, water has gradually become a green and sustainable alternative to traditional organic solvents which are generally hazardous waste productive. Due its safe, nontoxic, nonflammable, cost-effective, abundant nature, been increasingly used in various types of reactions ranging from conventional oxidation, reduction, addition, substitution, condensation, cyclization classical cross-coupling, CH activation more recent photoredox, electrochemical chemoenzymatic reactions. This chapter summarizes (2017-2022) representative examples using as solvent covers related reaction mechanisms roles that plays certain Micellar-enabled aqueous facilitated by surfactants will also be discussed.

Язык: Английский

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Homologations via Carbene‐Mediated Rearrangement Reactions

Опубликована: Май 26, 2023

This book chapter will provide a detailed discussion about homologation reaction by [1,2]-sigmatropic rearrangement of onium ylides via carbene transfer reactions. be divided into four subsections. (1) 1,2-Sigmatropic Rearrangement Onium Ylides Sigmatropic reactions are an important carbenes, and this is today one the most transformations. In we discuss advances that have been made using metal-catalyzed, bio engineered, photochemical for 1,2-sigmatropic (oxonium, sulfonium, selenium, ammonium, iodonium, etc.). (2) Homologation Reaction X–X X–Y Insertion Diazoalkane Carbene insertion fundamental interest in organic synthesis formation CC CX/Y bond. Widely used precursor such as diazoalkanes, N -sulfonyl-1,2,3-triazoles, tosylhydrazones can easily inserted CH; XH, YY, YZ bond under thermal, conditions where X N, Si, O, S, Se, P, or halogen Y Z B, etc. The key step these [1,2]-proton shift. (3) Ring Expansion application on ring expansion discussed detail chapter. DFT calculations mechanism study oxygen sulfur heterocycles studied Koenigs Xu group, they uncovered pathway proceeding diradical conditions, which really understanding free ylide mechanism,

Язык: Английский

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Asymmetric Carbene Insertion into Se‐S Bonds by Synergistic Rh(II)/Guanidine Catalysis Involving Chalcogen‐Bond Assistance

Angewandte Chemie, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 2, 2024

Abstract The efficient construction of chalcogen‐atom‐based chiral compounds remains a challenge, despite the importance organoselenium and organosulfur in life materials science. Chalcogen atoms can form net attractive interactions called chalcogen bonds, but it is an undeveloped tool to assist asymmetric catalysis. Herein, we report enantioselective insertion platform install stereogenic center bearing selenyl thiocyano functional groups. Our method operates by synergistic catalysis guanidine achiral dirhodium complex three‐component or four‐component reaction, through Se−S bond into carbene species, competing successfully with spontaneous racemic process showing high regioselectivity. As elucidated spectroscopic experiments computational studies, unique mechanism involving as well hydrogen bonding was established account for enantiocontrol. stereoselectivity holds broad array selenylthiocyanatopropanoates, which showed excellent anti‐inflammatory toward IL‐1β low cytotoxicity.

Язык: Английский

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1,3‐Difunctionalization of Imino‐Carbenes via Rhodium‐Catalyzed Reactions of Triazoles with Acyl Selenides

Advanced Synthesis & Catalysis, Год журнала: 2021, Номер 363(18), С. 4365 - 4370

Опубликована: Июль 23, 2021

Abstract Herein, we report on the rhodium‐catalyzed reaction of triazoles with acyl selenides. Under thermal conditions and in presence a rhodium catalyst, rapid 1,3‐difunctionalization occurs to provide valuable α‐seleno enamides high stereoselectivity broad functional group tolerance, which was demonstrated 35 examples up 95% yield. Computational calculations suggest pathway that gives direct access without intermittent formation ylide intermediates. magnified image

Язык: Английский

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A highly efficient method to access unprotected C-3 bifunctional quaternary 3-allyl-3-(amino)oxindoles

Organic & Biomolecular Chemistry, Год журнала: 2023, Номер 21(17), С. 3547 - 3551

Опубликована: Янв. 1, 2023

A highly efficient Rh(II) catalyzed non-radical protocol to access NH-free C-3 bifunctional oxindoles, which possess 3-allyl and 3-amino simultaneously, was first achieved by employing an intermolecular [2,3]-sigmatropic rearrangement reaction between diazooxindoles tertiary allylic amines. Utilizing readily available allylamines as the nitrogen allyl source concurrently, a wide range of bio-active 3-allyl-3-(amino)oxindoles were obtained in excellent yields under very mild conditions; meanwhile, TON can be up 90 000. Our study addresses gap literature investigating rearrangements ammonium ylides with diazoamides, have been relatively understudied.

Язык: Английский

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Carbenes and Nitrenes

Organic Reaction Mechanisms/Organic reaction mechanisms, Год журнала: 2023, Номер unknown, С. 141 - 177

Опубликована: Янв. 20, 2023

A general review has appeared on catalyst design assisted by computations featuring some examples of carbenes acting either as organocatalysts or in situ generated reagents metal-catalysed reactions. The decomposition propylamine and propylammonium the gas phase been investigated density functional theory composite quantum chemistry methods. formation carbene–borane complexes found numerous applications recent years allowed identification unprecedented reaction mechanisms. Computational studies have conducted mechanism lithium magnesium carbenoid cyclopropanations. reactivity photogenerated diphenylcarbene to be controlled presence additional protic molecules. Under metal-free conditions, nitrene-transfer reactions olefins are still challenging. development optimization aziridination under transition metal catalysis attracting much attention.

Язык: Английский

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