HFIP in Organic Synthesis

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(15), P. 12544 - 12747

Published: July 17, 2022

1,1,1,3,3,3-Hexafluoroisopropanol (HFIP) is a polar, strongly hydrogen bond-donating solvent that has found numerous uses in organic synthesis due to its ability stabilize ionic species, transfer protons, and engage range of other intermolecular interactions. The use this exponentially increased the past decade become choice some areas, such as C–H functionalization chemistry. In review, following brief history HFIP an overview physical properties, literature examples reactions using or additive are presented, emphasizing effect each reaction.

Language: Английский

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Enantioselective Aziridination of Unactivated Terminal Alkenes Using a Planar Chiral Rh(III) Indenyl Catalyst

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(2), P. 1447 - 1454

Published: Jan. 3, 2024

Chiral aziridines are important structural motifs found in natural products and various target molecules. They serve as versatile building blocks for the synthesis of chiral amines. While advances catalyst design have enabled robust methods enantioselective aziridination activated olefins, simple abundant alkyl-substituted olefins pose a significant challenge. In this work, we introduce novel approach utilizing planar rhodium indenyl to facilitate unactivated alkenes. This transformation exhibits remarkable degree functional group tolerance displays excellent chemoselectivity favoring alkenes over their counterparts, delivering wide range enantioenriched high-value aziridines. Computational studies unveil stepwise mechanism which alkene migratory insertion plays central role. process results formation strained four-membered metallacycle serves both enantio- rate-determining steps overall reaction.

Language: Английский

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Hydroxylamines As Bifunctional Single-Nitrogen Sources for the Rapid Assembly of Diverse Tricyclic Indole Scaffolds

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(14), P. 6698 - 6707

Published: March 17, 2020

Conventional approaches on using hydroxylamine derivatives as single nitrogen sources, for the construction of n-membered (n > 3) N-heterocycles, rely upon two chemical operations by involving sequential nucleophilic and electrophilic C–N bond formations. Here, we report a highly efficient cascade alkyne insertion/C–H activation/amination rapid preparation myriad tricyclic indoles, in single-step transformation, bifunctional secondary hydroxylamines. It is noteworthy that judicious selection applicable amino agents, enabling prior oxidative addition aryl iodide to initial Pd(0) species subsequent bonds formation, was key success this reaction. Control experiments indicated five-membered palladacyclic intermediate played crucial role promoting final aminative ring closure.

Language: Английский

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The advent of electrophilic hydroxylamine-derived reagents for the direct preparation of unprotected amines

Chemical Communications, Journal Year: 2022, Volume and Issue: 58(72), P. 9991 - 10003

Published: Jan. 1, 2022

Electrophilic aminating reagents have seen a renaissance in recent years as effective nitrogen sources for the synthesis of unprotected amino functionalities.

Language: Английский

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Cyclic Amine Synthesis via Catalytic Radical‐Polar Crossover Cycloadditions

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(18)

Published: Feb. 29, 2024

Abstract The rapid assembly of valuable cyclic amine architectures in a single step from simple precursors has been recognized as an ideal platform term efficiency and sustainability. Although vast number studies regarding synthesis reported, new synthetic disconnection approaches are still high demand. Herein, we report catalytic radical‐polar crossover cycloaddition to triggered primary sulfonamide under photoredox condition. This newly developed disconnection, comparable established approaches, will allow construct β, β‐disubstituted β‐monosubstituted derivatives efficiently. study highlights the unique utility bifunctional reagent, which acts radical precursor nucleophile. open‐shell methodology demonstrates broad tolerance various functional groups, drug natural products economically sustainable fashion.

Language: Английский

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Chiral Cp^xRhodium(III)‐Catalyzed Enantioselective Aziridination of Unactivated Terminal Alkenes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(12)

Published: Jan. 27, 2024

Chiral cyclopentadienyl-rhodium(III) Cp

Language: Английский

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Rh(III)-Catalyzed Three-Component Syn-Carboamination of Alkenes Using Arylboronic Acids and Dioxazolones

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(14), P. 8585 - 8590

Published: June 30, 2021

Herein, we report a Rh(III)-catalyzed three-component carboamination of alkenes from readily available aryl boronic acids as carbon source and dioxazolones nitrogen electrophiles. This protocol provides facile access to valuable amine products including α-amino acid derivatives in good yield regioselectivity without the need for directing functionality. A series experiments suggest mechanism which Rh(III) catalyst undergoes transmetalation with acid, followed by turnover limiting alkene migratory insertion into Rh(III)-aryl bond. Subsequently, fast Rh-nitrene formation syn-carboamination product selectively after reductive elimination proto-demetalation. Importantly, coupling preference variety two-component undesired byproducts.

Language: Английский

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Rhodium(III)-Catalyzed Anti-Markovnikov Hydroamidation of Unactivated Alkenes Using Dioxazolones as Amidating Reagents

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(49), P. 22426 - 22432

Published: Dec. 1, 2022

The amide is one of the most prevalent functional groups in all pharmaceuticals, and for this reason, reactions that introduce moiety are particular value. Intermolecular hydroamidation alkenes remains an underexplored method synthesis amide-containing compounds. majority procedures exhibit Markovnikov regioselectivity, while current methods anti-Markovnikov somewhat limited to activated alkene substrates or radical processes. Herein, we report a general intermolecular unactivated under mild conditions, utilizing Rh(III) catalysis conjunction with dioxazolone amidating reagents isopropanol as environmentally friendly hydride source. reaction tolerates wide range efficiently converts electron-deficient alkenes, styrenes, 1,1-disubstituted addition their corresponding linear amides. Mechanistic studies reveal reversible rhodium migratory insertion step, leading exquisite selectivity product.

Language: Английский

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Catalytic access to carbocation intermediates via nitrenoid transfer leading to allylic lactams

Nature Catalysis, Journal Year: 2020, Volume and Issue: 4(1), P. 79 - 88

Published: Dec. 21, 2020

Language: Английский

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Diastereoselective Three-Component 3,4-Amino Oxygenation of 1,3-Dienes Catalyzed by a Cationic Heptamethylindenyl Rhodium(III) Complex

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(43), P. 17964 - 17969

Published: Oct. 20, 2021

The direct oxyamination of olefins is a compelling tool to rapidly access β-amino alcohols–a privileged motif ubiquitous in natural products, pharmaceuticals and agrochemicals. Although variety expedient methods are established for simple alkenes, selective amino oxygenation 1,3-dienes less explored. Within this context, the that internal position remain unprecedented. We herein report modular three-component approach perform an highly diastereoselective catalyzed by cationic heptamethylindenyl (Ind*) Rh(III) complex.

Language: Английский

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