Recent advances in combining photo- and N-heterocyclic carbene catalysis

Chemical Science, Journal Year: 2023, Volume and Issue: 14(46), P. 13367 - 13383

Published: Jan. 1, 2023

This review summarizes recent advances in combining photo- and N-heterocyclic carbene catalysis, as well provides an outlook on future opportunities challenges.

Language: Английский

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Radical Reactions with N-Heterocyclic Carbene (NHC)-Derived Acyl Azoliums for Access to Multifunctionalized Ketones

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(11), P. 8270 - 8293

Published: May 13, 2024

As one of the most important key intermediates, NHC-bound acylazolium-based ionic transformations have been intensively explored in past two decades. With expeditious development NHC-catalyzed radical recent years, acylazolium chemistry has reached another level, with number relevant publications increasing significantly. However, a summary focused on acylations NHC-derived acyl azoliums classified according to mechanistic difference not reported. Such detailed classification and deep analysis provide opportunities for better understanding history trend this field. In review, reactions N-heterocyclic carbene (NHC)-derived are systematically introduced. The achievements challenges within area also summarized discussed at end.

Language: Английский

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Photoinduced Electron Transfer from Xanthates to Acyl Azoliums: Divergent Ketone Synthesis via N‐Heterocyclic Carbene Catalysis

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

Published: June 12, 2023

Considering the prevalence of alcohols and carboxylic acids, their fragment cross-coupling reactions could hold significant implications in organic synthesis. Herein, we report a versatile method for synthesizing diverse range ketones from acid derivatives via N-heterocyclic carbene (NHC) catalysis. Mechanistic investigations revealed that photoexcited xanthates acyl azoliums undergo single electron transfer (SET) under photocatalyst-free conditions, generating NHC-derived ketyl radicals alkyl radicals. These open-shell intermediates subsequently radical-radical reaction, yielding valuable ketones. Furthermore, this approach can be employed three-component involving alkenes enynes, resulting structurally cross-coupled The unified strategy offers unique opportunity coupling derivatives, accommodating functional groups even complex settings.

Language: Английский

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Light‐Driven Enantioselective Carbene‐Catalyzed Radical‐Radical Coupling

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(49)

Published: Oct. 17, 2023

Abstract An enantioselective carbene‐catalyzed radical‐radical coupling of acyl imidazoles and racemi c Hantzsch esters is disclosed. This method involves the an N‐heterocyclic carbene‐derived ketyl radical a secondary sp 3 ‐carbon allows access to chiral α‐aryl aliphatic ketones in moderate‐to‐good yields enantioselectivities without any competitive epimerization. The utility this protocol highlighted by late‐stage functionalization various pharmaceutical compounds further demonstrated transformation enantioenriched products biologically relevant molecules. Computational investigations reveal carbene controls double‐facial selectivity alkyl radicals, respectively.

Language: Английский

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Visible light-induced synthesis of 1,3-disubstituted bicyclo[1.1.1]pentane ketonesviacooperative photoredox and N-heterocyclic carbene catalysis

Green Chemistry, Journal Year: 2023, Volume and Issue: 25(10), P. 3909 - 3915

Published: Jan. 1, 2023

Visible light-induced highly efficient synthesis of 1,3-disubstituted bicyclo[1.1.1]pentane with mild conditions, high atom economy, and superior functional group tolerance.

Language: Английский

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Asymmetric imino-acylation of alkenes enabled by HAT-photo/nickel cocatalysis

Chemical Science, Journal Year: 2023, Volume and Issue: 14(23), P. 6449 - 6456

Published: Jan. 1, 2023

By merging nickel-mediated facially selective aza-Heck cyclization and radical acyl C-H activation promoted by tetrabutylammonium decatungstate (TBADT) as a hydrogen atom transfer (HAT) photocatalyst, we accomplish an asymmetric imino-acylation of oxime ester-tethered alkenes with readily available aldehydes the source, enabling synthesis highly enantioenriched pyrrolines bearing acyl-substituted stereogenic center under mild conditions. Preliminary mechanistic studies support Ni(i)/Ni(ii)/Ni(iii) catalytic sequence involving intramolecular migratory insertion tethered olefinic unit into Ni(iii)-N bond enantiodiscriminating step.

Language: Английский

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Cooperative Carbene Photocatalysis for β-Amino Ester Synthesis

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: unknown

Published: Oct. 31, 2023

β-Amino acids are useful building blocks of bioactive molecules, including peptidomimetics and pharmaceutical compounds. The current limited accessibility to β2,2-type amino which bear an α-quaternary center has their use in chemical synthesis biological investigations. Disclosed herein is the development a new N-heterocyclic carbene/photocatalyzed aminocarboxylation olefins, affording β2,2-amino esters with high regioselectivity. generation nitrogen-centered radicals derived from simple imides via sequence deprotonation single-electron oxidation allows for subsequent addition geminal-disubstituted olefins regioselectively. intermediate tertiary then cross-couple stabilized azolium-based radical generated situ efficiently construct quaternary centers. Mechanistic studies, Stern–Volmer fluorescence quenching experiments, support proposed catalytic cycle.

Language: Английский

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Radical Acylation of Alkenes by NHC‐Organocatalysis

European Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 26(48)

Published: Oct. 11, 2023

Abstract N ‐Heterocyclic carbene (NHC) catalyzed radical‐radical reactions have been proven to be powerful strategies for assembling ketyl‐containing compounds via single electron transfer (SET) pathway under either thermal conditions or photoredox conditions. In this context, acylation of alkenes radical relay NHC‐organocatalysis has also opened a new window the difunctionalization construct valuable molecules in organic synthesis. review, advances and progress were summarized according different ways generation key NHC‐bound ketyl‐type radicals. Furthermore, reaction scopes, limitations mechanisms discussed based on types catalytic systems. Conclusions perspectives put forward at end.

Language: Английский

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Diastereoselective congested β-amido ketone synthesis via NHC-catalyzed radical-radical coupling

Chem Catalysis, Journal Year: 2023, Volume and Issue: 3(9), P. 100736 - 100736

Published: Aug. 31, 2023

Language: Английский

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N-heterocyclic carbene and photocatalyst-catalyzed rapid access to indole ketones via radical C(sp³)–H acylation

Green Chemistry, Journal Year: 2024, Volume and Issue: 26(9), P. 5397 - 5408

Published: Jan. 1, 2024

Carbene and photocatalyst-catalyzed rapid access to indole ketones via radical C(sp 3 )–H acylation.

Language: Английский

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