C–H functionalization with alkenes, allenes, and alkynes by half-sandwich rare-earth catalysts

Tetrahedron, Journal Year: 2023, Volume and Issue: 135, P. 133323 - 133323

Published: Feb. 23, 2023

Language: Английский

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Enantioselective [2+2] Cycloaddition of Allenyl Imide with Mono‐ or Disubstituted Alkenes

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(44)

Published: Sept. 14, 2022

Abstract An efficient catalytic asymmetric [2+2] cycloaddition of allenyl imide and mono‐ or disubstituted alkenes is disclosed. The key feature this method the use bidentate weakly activated less steric hindered alkene pair by utilizing chiral magnesium(II) complex N , N′ ‐dioxide, which could provide through‐space dispersion interactions to orientate arrangement alkene. This protocol allows generation a series axially cyclobutenes four‐membered ring‐containing spirocycles (80 examples) in high yield (up 99 %) with excellent enantioselectivity >99 % ee ), late‐stage modification biologically active molecules as well. Experimental studies DFT calculations revealed that proceeded via stepwise mechanism involving short‐lived zwitterionic intermediate. π‐π interaction between amide moiety ligand was crucial for enantiocontrol.

Language: Английский

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Expedient Access to Enantioenriched 1‐Azaspiro Cyclobutanones Enabled by Modified Heyns Rearrangement

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: June 13, 2023

Leveraging the unexplored regions of chemical space, integration spirocyclic cyclobutane in a molecular scaffold opens up new vista modern drug discovery. Despite recent advancements achieving synthesis such motifs, strategies for their asymmetric construction have not been well-recognized and remain formidable challenge. Herein, first time, we demonstrated chiral Brønsted acid-catalyzed enantioselective 1-azaspiro cyclobutanone enabled by an unusual reactivity enamine that explore potentiality Heyns rearrangement upon electrophilic modification. This design strategy offers viable access to wide range containing spiroindoline spiropyrrolidine derivatives good yields with excellent stereoselectivities (up >99 % ee, >20 : 1 dr). Furthermore, practicality this methodology has shown scale-up products facile post-synthetic modifications.

Language: Английский

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Tunable Regiodivergent Reactivity of N-Allenamides with Silacyclobutanes via Palladium Catalysis in the Synthesis of Silacyclic β-Aminosilanes

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(14), P. 10882 - 10892

Published: July 4, 2024

The key structure of β-aminosilanes has attracted significant interest because their latent biological activities in the field medicinal chemistry. However, structural variety been significantly constrained by absence a comprehensive synthetic approach. Thus, development regiodivergent catalytic systems for construction structurally diverse via an intermolecular cycloaddition strategy would represent addition to limited toolkit available synthesis. We herein present attractive approach synthesis through regioselective N-allenamides with expansion silacyclobutanes catalyzed Pd/PR3. Just selecting suitable protecting group N-allenamides, regioselectivity is completely switched efficiently provide two regioisomers silacyclic β-aminosilanes. Two regioselectivities were proceeded during migratory insertion and reductive elimination process, origin which could be well rationalized using density functional theory calculations.

Language: Английский

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Recent Advances in Non-Precious Metal Catalysis

Organic Process Research & Development, Journal Year: 2022, Volume and Issue: 26(8), P. 2281 - 2310

Published: Aug. 2, 2022

This review provides a summary of recently published developments in the field nonprecious metal catalysis (NPMC) and highlights range synthetic applications captured research between July October 2021. is an installment series on this area briefing Ni, Cu, Fe, Co catalysis. There has been evident increase publications NPMC, which indicates widespread interest among laboratories academia industry development utilization catalytic these metals.

Language: Английский

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Regio‐ and Diastereoselective Formal [2+2] Cycloaddition of Allenes with Amino‐Functionalized Alkenes by Rare‐Earth‐Catalyzed C(sp²)−H Activation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(45)

Published: Sept. 19, 2022

The [2+2] cycloaddition of allenes with alkenes is much interest and importance as a straightforward route for the construction four-membered carbocycles but has remained underexplored to date. Herein we report first time intermolecular regio- diastereoselective formal wide range amino-functionalized by half-sandwich rare-earth catalysts. reaction proceeded through an allene C(sp2 )-H activation mechanism initiated site-selective deprotonation unit metal alkyl species followed alkene insertion into resulting metal-allenyl bond subsequent intramolecular C=C bond. This protocol offers unique synthesis new family cyclobutane cyclobutene derivatives which were difficult access previously.

Language: Английский

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Construction of C–N and C–O bonds based on N-allenamide functionalization

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(46), P. 9069 - 9084

Published: Jan. 1, 2022

The review covers recent advances in the development of new methods involving amination and alkoxylation reactions on N -allenamides covering cycloaddition, carbofunctionalization, halogenofunctionalization as well hydrofunctionalization reactions.

Language: Английский

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Multicomponent Assembly of Complex Oxindoles by Enantioselective Cooperative Catalysis

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(51)

Published: Oct. 21, 2022

Chiral oxindoles are important chemical scaffolds found in many natural products, and their enantioselective synthesis thus attracts considerable attention. Highly diastereo- synthetic methods for constructing C3 quaternary have been well-developed. However, the efficient of chiral 3-substituted tertiary has rarely reported due to ease racemization stereocenter via enolization. Therefore, we herein report on multicomponent assembly (from N-aryl diazoamides, aldehydes, enamines/indoles) complex by cooperative catalysis. These reactions proceed under mild conditions show broad substrate scope, affording desired coupling products (>90 examples) with good excellent stereocontrol. Additionally, this research also demonstrates potential annulation 6,6,5-tricyclic lactone core structure Speradine A.

Language: Английский

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Concerted Enantioselective [2+2] Cycloaddition Reaction of Imines Mediated by a Magnesium Catalyst

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 145(1), P. 610 - 625

Published: Dec. 20, 2022

Enantioselective [2 + 2] cyclization between an imine and a carbon–carbon double bond is versatile strategy to build chiral azetidines. However, α-branched allenoates have never been successfully applied in reactions with imines, as they always undergo Kwon's [4 annulation previous catalytic methods. Herein, simple situ generated magnesium catalyst was employed achieve the enantioselective reaction of DPP-imines for first time. Insightful experiments including KIE experiments, controlled Hammett plot analysis, 31P NMR studies initial intermediates indicate that current most likely involves asynchronous concerted transition state. Further mechanistic investigations by combining kinetic studies, ESI coordination complexes, on rates under different loading amounts provided details this allenoates. This new approach synthesis various aza-heterocycles, key intermediate lipid-lowering agent Ezetimibe.

Language: Английский

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Palladium-Catalyzed Regioselective [3 + 2] Annulation with N-Allenamides at the Proximal C═C Bond: Synthesis of γ-Amino-α′-methylenecyclopentenones

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: April 10, 2025

A palladium-catalyzed [3 + 2] cycloaddition of cyclopropenones with N-allenamides has been developed. This methodology facilitates the synthesis γ-amino-α'-methylenecyclopentenones in moderate to excellent yields good regioselectivity and compatibility various functional groups. The employment as versatile 2C synthons enables simultaneous incorporation both a nitrogen atom methylene group into cyclopentenones. Furthermore, this approach exhibits reverse when compared general allenes. Density theory calculations successfully elucidated origin observed regioselectivity.

Language: Английский

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