Tandem Iridium Catalysis as a General Strategy for Atroposelective Construction of Axially Chiral Styrenes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(28), P. 10686 - 10694

Published: July 6, 2021

Axially chiral styrenes are of great interest since they may serve as a class novel ligands in asymmetric synthesis. However, only recently have strategies been developed for their enantioselective preparation. Thus, the development and efficient methodologies is highly desirable. Herein, we reported first tandem iridium catalysis general strategy synthesis axially enabled by Asymmetric Allylic Substitution-Isomerization (AASI) using cinnamyl carbonate analogues electrophiles naphthols nucleophiles. In this approach, were generated through two independent iridium-catalytic cycles: iridium-catalyzed allylic substitution situ isomerization via stereospecific 1,3-hydride transfer catalyzed same catalyst. Both experimental computational studies demonstrated that proceeded benzylic C–H bond oxidative addition, followed terminal reductive elimination. Amid central-to-axial chirality transfer, hydroxyl naphthol plays crucial role ensuring stereospecificity coordinating with Ir(I) center. The process accommodated broad functional group compatibility. products excellent yields to high enantioselectivities, which could be transformed various molecules.

Language: Английский

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Enantioselective Oxidative Multi-Functionalization of Terminal Alkynes with Nitrones and Alcohols for Expeditious Assembly of Chiral α-Alkoxy-β-amino-ketones

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(36), P. 14703 - 14711

Published: Aug. 31, 2021

Catalytic oxidative functionalization of alkynes has emerged as an effective method in synthetic chemistry recent decades. However, enantioselective transformations via metal carbene intermediates are quite rare due to the lack robust chiral catalysts, especially intermolecular versions. Herein, we report first asymmetric three-component reaction commercially available with nitrones and alcohols, which affords α-alkoxy-β-amino-ketones good yields high excellent enantioselectivity using combined catalysis by achiral gold complex a spiro phosphoric acid (CPA). Mechanistically, this atom-economic involves catalytic alkyne oxidation/ylide formation/Mannich-type addition sequence that uses nitrone oxidant leaving fragment imine electrophile, providing novel for multi-functionalization terminal alkynes.

Language: Английский

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Dearomative logic in natural product total synthesis

Natural Product Reports, Journal Year: 2022, Volume and Issue: 39(12), P. 2231 - 2291

Published: Jan. 1, 2022

This review explores the strategies and tactics of effective dearomative retrosynthetic logic, illustrated through numerous outstanding examples contemporary natural product total synthesis.

Language: Английский

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Recent advances in iridium-catalyzed enantioselective allylic substitution using phosphoramidite-alkene ligands

Catalysis Science & Technology, Journal Year: 2022, Volume and Issue: 12(13), P. 4100 - 4112

Published: Jan. 1, 2022

This minireview describes the recent progress of iridium-catalyzed enantioselective allylic substitution using phosphoramidite-alkene ligands realizing highly carbon–carbon and carbon–heteroatom bond formation.

Language: Английский

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Asymmetric allylic substitution–isomerization to axially chiral enamides via hydrogen-bonding assisted central-to-axial chirality transfer

Chemical Science, Journal Year: 2020, Volume and Issue: 11(37), P. 10119 - 10126

Published: Jan. 1, 2020

Axially chiral enamides bearing a N–C axis have been recently studied and were proposed to be valuable building blocks, but stereoselective synthesis has not achieved.

Language: Английский

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Highly Enantioselective Iridium-Catalyzed Coupling Reaction of Vinyl Azides and Racemic Allylic Carbonates

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(31), P. 13398 - 13405

Published: July 14, 2020

The iridium-catalyzed enantioselective coupling reaction of vinyl azides and allylic electrophiles is presented provides access to β-chiral carbonyl derivatives. Vinyl are used as acetamide enolate or acetonitrile carbanion surrogates, leading γ,δ-unsaturated β-substituted amides well nitriles with excellent enantiomeric excess. These products readily transformed into chiral N-containing building blocks pharmaceuticals. A mechanism proposed rationalize the chemoselectivity this reaction.

Language: Английский

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Regio- and Enantioselective Decarboxylative Allylic Benzylation Enabled by Dual Palladium/Photoredox Catalysis

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(2), P. 1428 - 1432

Published: Jan. 10, 2022

A decarboxylative allylic benzylation cocatalyzed by Pd/photoredox in a regio- and enantioselective manner has been achieved. Readily available aryl acetic acids are used as benzylic nucleophile equivalents without preactivation. This mild atom-economical protocol expands the scope of coupling partners electrophiles. Vinyl epoxides could also go through this transformation smoothly, affording various chiral homoallylic alcohols bearing all-carbon quaternary stereocenters.

Language: Английский

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Asymmetric Allylation by Chiral Organocatalyst‐Promoted Formal Hetero‐Ene Reactions of Alkylgold Intermediates

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(4), P. 1992 - 1999

Published: Oct. 2, 2020

Abstract An unprecedented catalytic asymmetric allylation of isatins and isatin‐derived ketimines is reported enabled by a gold chiral organocatalyst cooperative catalysis strategy. This method offers expeditious access to 2,5‐disubsituted alkylideneoxazolines containing vicinal stereogenic centers, mainly in optically pure form, which are otherwise impossible access. Mechanistic evidence reveals the presence an alkylgold intermediate, X‐ray crystal structure allylgold species illuminates its unique stability reactivity. formal hetero‐ene reaction this involving dearomatization process, with assistance quinine‐derived squaramide catalyst. novel discovery extends synthetic applications complexes versatility catalysis.

Language: Английский

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Design and Application of Indole‐Based Allylic Donors for Pd‐Catalyzed Decarboxylative Allylation Reactions^†

Chinese Journal of Chemistry, Journal Year: 2020, Volume and Issue: 38(12), P. 1612 - 1618

Published: July 13, 2020

Summary of main observation and conclusion A new class indole‐based allylic donors have been designed developed for palladium‐catalyzed decarboxylative allylations. In addition, the first application these in [3+2] cycloaddition amination has achieved by reacting with isocyanates sulfonyl amines, respectively. This approach represents design donors, which is helpful settling challenge designing developing heterocycle‐based Pd‐catalyzed allylation reactions. Moreover, this cycloadditions substitutions will add contents to research field allylation.

Language: Английский

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Iridium-Catalyzed Diastereo- and Enantioselective [4 + 3] Cycloaddition of 4-Indolyl Allylic Alcohols with Azomethine Ylides

Organic Letters, Journal Year: 2021, Volume and Issue: 23(2), P. 588 - 594

Published: Jan. 6, 2021

An unprecedented iridium-catalyzed asymmetric [4 + 3] cycloaddition of racemic 4-indolyl allylic alcohols with azomethine ylides is reported. The ability acid promoter zinc triflate to perform multiple roles the key factor for success this strategy. This method provides scalable and efficient access biologically important azepino[3,4,5-cd] indoles in good yields generally excellent diastereo- enantioselectivities (up >20:1 dr >99% ee). Mild reaction conditions, easily accessible substrates chiral catalyst, broad substrate scope highlight practicality methodology.

Language: Английский

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