Applications of Halogen-Atom Transfer (XAT) for the Generation of Carbon Radicals in Synthetic Photochemistry and Photocatalysis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2292 - 2352

Опубликована: Дек. 9, 2021

The halogen-atom transfer (XAT) is one of the most important and applied processes for generation carbon radicals in synthetic chemistry. In this review, we summarize highlight aspects associated with XAT impact it has had on photochemistry photocatalysis. organization material starts analysis mechanistic then follows a subdivision based nature reagents used halogen abstraction. This review aims to provide general overview fundamental concepts main agents involved objective offering tool understand facilitate development new radical strategies.

Язык: Английский

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Multicomponent reactions and photo/electrochemistry join forces: atom economy meets energy efficiency

Chemical Society Reviews, Год журнала: 2022, Номер 51(6), С. 2313 - 2382

Опубликована: Янв. 1, 2022

Visible-light photoredox catalysis has been regarded as an extremely powerful tool in organic chemistry, bringing the spotlight back to radical processes. The versatility of photocatalyzed reactions already demonstrated be effective providing alternative routes for cross-coupling well multicomponent reactions. photocatalyst allows generation high-energy intermediates through light irradiation rather than using highly reactive reagents or harsh reaction conditions. In a similar vein, electrochemistry experienced fruitful renaissance generating without need any catalyst. Such milder approaches pose basis toward higher selectivity and broader applicability. electrochemical reactions, species acts starter cascade events. This diverse reactivity use is usually not covered by classical methods. Owing availability cheaper more standardized photo- reactors, easily scalable flow-setups, it surprising that these two fields have become areas increased research interest. Keeping view, this review aimed at overview synthetic design MCRs involving and/or activation crucial step with particular focus on choice difunctionalized reagent.

Язык: Английский

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Radical Carbonyl Umpolung Arylation via Dual Nickel Catalysis

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(4), С. 1899 - 1909

Опубликована: Янв. 18, 2022

The formation of carbon-carbon bonds lies at the heart synthetic organic chemistry and is widely applied to construct complex drugs, polymers, materials. Despite its importance, catalytic carbonyl arylation remains comparatively underdeveloped, due limited scope functional group tolerance. Herein we disclose an umpolung strategy achieve radical via dual catalysis. This redox-neutral approach provides a complementary method Grignard-type products from (hetero)aryl bromides aliphatic aldehydes, without need for pre-functionalization. A sequential activation, hydrogen-atom transfer, halogen atom transfer process could directly convert aldehydes corresponding ketyl-type radicals, which further react with aryl-nickel intermediates in overall polarity-reversal process. tolerates─among others─acidic groups, heteroaryl motifs, sterically hindered substrates has been late-stage modification drugs natural products.

Язык: Английский

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Multicomponent Synthesis of α-Branched Amines via a Zinc-Mediated Carbonyl Alkylative Amination Reaction

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(13), С. 9045 - 9062

Опубликована: Март 15, 2024

Methods for the synthesis of α-branched alkylamines are important due to their ubiquity in biologically active molecules. Despite development many methods amine preparation, C(sp3)-rich nitrogen-containing compounds continue pose challenges synthesis. While carbonyl reductive amination (CRA) between ketones and is cornerstone method alkylamine synthesis, it sometimes limited by sterically demanding condensation step dialkyl amines more restricted availability compared aldehydes. We recently reported a "higher-order" variant this transformation, alkylative (CAA), which utilized halogen atom transfer (XAT)-mediated radical mechanism, enabling streamlined complex alkylamines. efficacy visible-light-driven approach, displayed scalability issues, competitive was problem certain substrate classes, limiting applicability. Here, we report change reaction regime that expands CAA platform through realization an extremely broad zinc-mediated reaction. This new strategy enabled elimination CRA, simplified purification, improved scope. Furthermore, harnessed carboxylic acid derivatives as alkyl donors facilitated α-trialkyl tertiary amines, cannot be accessed via CRA. Zn-mediated can carried out at variety scales, from 10 μmol setup microtiter plates high-throughput experimentation, gram-scale medicinally-relevant compounds. believe transformation enables robust, efficient, economical access provides viable alternative current benchmark methods.

Язык: Английский

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Modular α-tertiary amino ester synthesis through cobalt-catalysed asymmetric aza-Barbier reaction

Nature Chemistry, Год журнала: 2023, Номер 16(3), С. 398 - 407

Опубликована: Дек. 11, 2023

Язык: Английский

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Phenanthroline-Initiated Anti-selective Hydrosulfonylation of Unactivated Alkynes with Sulfonyl Chlorides

ACS Catalysis, Год журнала: 2023, Номер 13(10), С. 6983 - 6993

Опубликована: Май 8, 2023

A simple and general method for anti-selective hydrosulfonylation of unactivated alkynes with sulfonyl chlorides in the presence a catalytic amount phenanthroline-based Lewis base (Me3Si)3SiH as hydrogen atom donor has been developed. The protocol proceeds efficiently under mild metal-free conditions, delivering diverse set (Z)-vinyl sulfones high stereoselectivity. Additionally, displays excellent functional-group compatibility can be applied to late-stage modifications complex drugs their derivatives. Experimental density functional theory studies unveiled that key transformation's success is employment base, which interacts form halogen-bond accelerates cleavage S–Cl bonds irradiation visible light.

Язык: Английский

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Cobalt‐Catalyzed Enantioselective Reductive α‐Chloro‐Carbonyl Addition of Ketimine to Construct the β‐Tertiary Amino Acid Analogues

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(25)

Опубликована: Янв. 22, 2024

β-Tertiary amino acid derivatives constitute one of the most frequently occurring units in natural products and bioactive molecules. However, efficient asymmetric synthesis this motif still remains a significant challenge. Herein, we disclose cobalt-catalyzed enantioselective reductive addition reaction ketimine using α-chloro carbonyl compound as radical precursor, providing expedient access to diverse array enantioenriched β-quaternary analogues. This protocol exhibits outstanding enantioselectivity broad substrate scope with excellent functional group tolerance. Preliminary mechanism studies rule out possibility Reformatsky-type confirm involvement species stereoselective process. The synthetic utility has been demonstrated through rapid assembly iterative oligopeptide, showcasing its versatile platform for late-stage modification drug candidates.

Язык: Английский

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Challenges and recent advancements in the synthesis of α,α-disubstituted α-amino acids

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Фев. 17, 2024

α,α-Disubstituted α-amino acids (α-AAs) have improved properties compared to other types of amino acids. They serve as modifiers peptide conformation and precursors bioactive compounds. Therefore, it has been a long-standing goal construct this highly valuable scaffold efficiently in organic synthesis drug discovery. However, access α,α-disubstituted α-AAs is challenging largely unexplored due their steric constraints. To overcome these, remarkable advances made the last decades. Emerging strategies such synergistic enantioselective catalysis, visible-light-mediated photocatalysis, metal-free methodologies CO

Язык: Английский

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Photoinitiated anti‐Hydropentafluorosulfanylation of Terminal Alkynes

Angewandte Chemie International Edition, Год журнала: 2021, Номер 61(1)

Опубликована: Окт. 30, 2021

A photoinitiated anti-hydropentafluorosulfanylation of terminal alkynes using SF5 Cl and (TMS)3 SiH as the hydrogen atom donor is reported. This transformation generates selectively (Z)-(1-alken-1-yl)pentafluoro-λ6 -sulfanes (Z:E : >85:15), thus allowing preparation this previously unknown geometrical isomer. DFT calculations highlight that selectivity due to intrinsic preference -substituted vinylic radicals adopt a cis geometry, increased steric contacts during transition structures leading minor (E)-products.

Язык: Английский

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Direct Access to α‐Aminosilanes Enabled by Visible‐Light‐Mediated Multicomponent Radical Cross‐Coupling

Angewandte Chemie International Edition, Год журнала: 2021, Номер 60(43), С. 23335 - 23341

Опубликована: Авг. 25, 2021

α-Aminosilanes are an important class of organic compounds that show biological activity. In this communication, a new approach to α-aminosilanes utilizes photoredox catalysis enable three-component coupling organo(tristrimethylsilyl)silanes with feedstock alkylamines and aldehydes is presented. A wide range highly functionalized can be obtained in good yields under mild conditions. Both primary amines secondary compatible transformation. Moreover, optically pure accessible by using chiral amines. Mechanistic studies indicate reactions proceed through radical/radical cross-coupling silyl radicals α-amino alkyl radicals.

Язык: Английский

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