In the presence of a catalytic amount of iron(III) acetylacetonate [Fe(acac) ], the reaction of structurally diverse ketoxime esters with trimethylsilyl azide (TMSN ) afforded γ-azido ketones in good to excellent yields. This unprecedented distal γ-C(sp )-H bond azidation reaction went through a sequence of reductive generation of an iminyl radical, 1,5-hydrogen atom transfer (1,5-HAT) and iron-mediated redox azido transfer to the translocated carbon radical. TMSN served not only as a nitrogen source to functionalise the unactivated C(sp )-H bond, but also as a reductant to generate the catalytically active Fe species in situ. Based on the same principle, a novel β-C(sp )-H functionalisation of alcohols via N-acyloxy imidates was subsequently realised, leading, after hydrolysis of the resulting ester, to β-azido alcohols, which are important building blocks in organic and medicinal chemistry.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1002/chem.201901079 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Visible-Light-Promoted Decarboxylative Alkylation/Cyclization of Vinylcycloalkanes.
J Org Chem
July 2023
Department of Chemistry and Chemical Engineering, Hunan Institute of Science and Technology, Yueyang 414006, China.
An efficient strategy for visible-light-promoted decarboxylative alkylation of vinylcyclopropanes with alkyl -(acyloxy)phthalimide esters through the dual C-C bond and single N-O bond cleavage, employing triphenylphosphine and lithium iodide as the photoredox system to synthesize 2-alkylated 3,4-dihydronaphthalenes, has been established. This alkylation/cyclization involves a radical process and undergoes a sequence of -(acyloxy)phthalimide ester single-electron reduction, N-O bond cleavage, decarboxylative, alkyl radical addition, C-C bond cleavage, and intramolecular cyclization. Moreover, using the photocatalyst Na-Eosin Y instead of triphenylphosphine and lithium iodide, the vinyl transfer products are acquired when vinylcyclobutanes or vinylcyclopentanes are utilized as alkyl radical receptors.
View Article and Find Full Text PDFPhotocatalytic cross-couplings the cleavage of N-O bonds.
Chem Commun (Camb)
September 2021
Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, P. R. China.
-(Acyloxy)phthalimide and oxime derivatives containing N-O bonds are important chemicals and synthetic intermediates, and visible light photoredox reductions of the N-O bonds provide carbon- or nitrogen-centered radicals for -(acyloxy)phthalimide derivatives and iminyl radicals for oxime derivatives. This feature article summarises the recent progress in the visible light photoredox organic reactions, including decarboxylative addition reactions, alkylation, allylation, alkenylation, alkynylation, arylation, heteroarylation and cascade annulation of -(acyloxy)phthalimide derivatives through the formation of carbon-carbon bonds, decarboxylative borylation, amination, oxygenation, sulfuration, selenylation, fluorination and iodination of -(acyloxy)phthalimide derivatives through the formation of carbon-heteroatom bonds, and additions to arenes and alkenes, hydrogen atom transfer and the cleavage of α-carbon-carbon bonds the iminyl radical intermediates for oxime derivatives.
View Article and Find Full Text PDFIron-Catalysed Remote C(sp³)-H Azidation of -Acyl Oximes and -Acyloxy Imidates.
Chimia (Aarau)
April 2021
Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, CH-1015 Lausanne, Switzerland;, Email:
The azido group occupies an important position in modern organic chemistry, broadly used as amine surrogates and as anchors in bioconjugation. Despite their importance, examples of selective direct azidation of inert C(sp³)-H bonds remain limited and often require strong oxidative conditions. Herein, we highlight the use of -acyl oximes and -acyloxy imidates as directing groups for the selective iron-catalysed azidation of C(sp³)-H bond with trimethylsilyl azide, giving access to various γ-azido ketones and β-azido alcohols in moderate to excellent yields.
View Article and Find Full Text PDFLate-Stage Alkylation of Heterocycles Using N-(Acyloxy)phthalimides.
Chem Asian J
April 2021
Department of Chemistry, Indian Institute of Technology Jodhpur, Karwar, 342037, Rajasthan, India.
Synthetic methods enabling late-stage modification of heterocycles hold tremendous importance in the pharmaceutical and agrochemical industry and drug discovery. Accordingly, efficient, functional group tolerant and selective late-stage alkylation of valuable molecular entities is of enormous significance and well-acknowledged in medicinal chemistry. Radical alkylation of heteroarenes employing carboxylic acids as the alkyl radical precursor represents one of the most direct ways of C-H functionalizations of heterocycles.
View Article and Find Full Text PDFIron-Catalysed Remote C(sp )-H Azidation of O-Acyl Oximes and N-Acyloxy Imidates Enabled by 1,5-Hydrogen Atom Transfer of Iminyl and Imidate Radicals: Synthesis of γ-Azido Ketones and β-Azido Alcohols.
Chemistry
July 2019
Laboratory of Synthesis and Natural Products, Institute of Chemical Sciences and Engineering, École Polytechnique Fédérale de Lausanne, EPFL-SB-ISIC-LSPN, BCH 5304, 1015, Lausanne, Switzerland.
In the presence of a catalytic amount of iron(III) acetylacetonate [Fe(acac) ], the reaction of structurally diverse ketoxime esters with trimethylsilyl azide (TMSN ) afforded γ-azido ketones in good to excellent yields. This unprecedented distal γ-C(sp )-H bond azidation reaction went through a sequence of reductive generation of an iminyl radical, 1,5-hydrogen atom transfer (1,5-HAT) and iron-mediated redox azido transfer to the translocated carbon radical. TMSN served not only as a nitrogen source to functionalise the unactivated C(sp )-H bond, but also as a reductant to generate the catalytically active Fe species in situ.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!