C–C Bond Acylation of Oxime Ethers via NHC Catalysis

Yang, Haibin; Wan, Dan-Hong

doi:10.1021/acs.orglett.0c04248

Cited by 31 publications

(6 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…fac -[Ir(ppy) 3 ] was purchased from Acros Organics. All of the cyclopentanone O -acyl oxime esters 1 were synthesized from the corresponding cycloketones and carboxylic acids according to the literature. , All of the NMR spectra of the known compounds were in full accordance with the data in the literature. Unless otherwise noted, materials obtained from commercial suppliers were used without further purification.…”

Section: Experimental Sectionmentioning

confidence: 93%

“…Recently, cyclobutenone oxime esters − and substituted cyclopentanone oxime esters − were considered as good alkyl nitrile precursors for the construction of desired products. With our continuous interest in the C–C bond cleavage of cycloketoxime esters, − herein, we report a visible-light-induced redox-neutral etherification of ketoxime esters with the only requirement of photoredox catalyst, which is treated as an alternative route producing varied oxygenated ring-opening products from five-membered to eight-membered and linear cycloketoxime esters (Scheme d).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Photoinduced Etherification of Less-Strained Cycloketoxime Esters Enabled by C–C Bond Cleavage

Wang

Chen

et al. 2022

J. Org. Chem.

View full text Add to dashboard Cite

We report a general, scalable, and convenient photochemical process for diversities of distal oxygenated nitriles from corresponding less-strained ketoxime esters allowing one-step introductions of ether and cyano groups, which avoids the utilization of toxic cyanide reagents. A wide range of ketoxime esters involving five-membered to eight-membered cycloketoxime esters and linear ketoxime esters participate smoothly under operately simple and mild conditions, affording structurally variable ring-opening products.

show abstract

Section: Experimental Sectionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Photoinduced Etherification of Less-Strained Cycloketoxime Esters Enabled by C–C Bond Cleavage

Wang

Chen

et al. 2022

J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Recently, several groups have utilized such reagents for the preparation of functionalized nitriles (Scheme ). In 2021, the groups of Yang and Guo independently reported the NHC-catalyzed radical cross-coupling between cyclic oxime ethers and aromatic aldehydes, yielding ketonitriles. Upon addition of styrene derivatives to the reaction mixture, Guo and Du further extended that strategy and reported an NHC-catalyzed intermolecular, three-component 1,2-cyanoalkylacylation of alkenes with readily available aldehydes and oxime esters.…”

Section: Ketyl Radicals Generated Via Single-electron Oxidation Using...mentioning

confidence: 99%

Radical NHC Catalysis

2022

View full text Add to dashboard Cite

Radical/radical cross-coupling reactions represent an efficient and straightforward approach for the construction of chemical bonds and accordingly have drawn increasing attention over the past decades. In order to achieve synthetically useful transformations, a persistent radical should be coupled with a transient radical in accordance with the persistent radical effect (PRE). However, known transient radicals outnumber by far the known types of free persistent radicals, which limits the widespread application of the PRE, until today. Thus, the development of efficient cross-coupling reactions between transient radicals has been in focus, and meanwhile transition-metal catalysis has been successfully implemented to artificially prolong radical lifetimes, allowing their utilization in formal radical/radical cross-couplings. Complementary research in the field recently uncovered that organocatalytically generated NHC-derived ketyl radicals are a type of catalytically generated free persistent radicals. NHC-catalyzed radical transformations of aldehydes and carboxylic acid derivatives have enabled the disclosure of an ever-increasing number of interesting reactions, which are different from traditional NHC-catalyzed ionic processes, offering otherwise inaccessible activation modes. These discoveries have opened a door to NHC organocatalysis for the manipulation of radical reactions. Due to its obvious potential in synthetic organic chemistry, it is timely to provide a perspective on this emerging field.

show abstract

“…Cyclic oxime derivatives are also good precursors of alkyl radicals, which tend to undergo β-elimination to afford the corresponding β-cyano alkyl radicals under single-electron reduction conditions for the preparation of functionalized nitriles (Scheme 17). In 2021, Yang's 36 and Guo's 37 groups independently reported the NHC-catalyzed radical ring-opening acylation of oxime esters with aromatic aldehydes. Employing six-membered thiazolium salt NHC-2 as catalyst in DMSO, a series of cyclic oxime esters could smoothly release the corresponding alkyl radicals which could be transformed into diverse ketonitriles in moderate to good yields under mild conditions.…”

Section: N-heterocyclic-carbene-catalyzed Radical Cross-coupling Acyl...mentioning

confidence: 99%