Amination of C-H bonds activated by ether oxygen atoms is facile with chloramine-T as nitrene source and copper(I) chloride in acetonitrile as catalyst. For cyclic ethers the hemiaminal products are generally stable and can be isolated pure. For acyclic ethers, the hemiaminal products, as expected, fragment with elimination of alcohol to yield imines. When activation of benzylic positions is remote through a conjugated system, stable benzylamine derivatives are isolated. Mechanistic studies are consistent with concerted insertion of an electrophilic nitrenoid into the C-H bond in the rate-determining step, though in an asynchronous manner with a more activated substrate.
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http://dx.doi.org/10.1039/b410883c | DOI Listing |
J Org Chem
January 2024
School of Chemistry & Chemical Engineering, Yangzhou University, Yangzhou, 225009, China.
An iodoform-promoted functionalization of ether with secondary sulfonyl amides under visible-light irradiation was developed toward synthesis of hemiaminal skeleton with good to excellent isolated yields. The characterization of the isolated ether and iodoform complex revealed regioselective hydrogen atom transfer to initiate carbon radical formation and enabled the amination reaction with the sulfonamide.
View Article and Find Full Text PDFChem Asian J
October 2023
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, India.
Fragile hemiaminal ether linkages present in the backbone of koneramines (L OR'), tridentate ligands, bound to copper(II) in stereoselectively self-assembled syn-[Cu(L OR')X ] complexes were transformed into sturdy methylene linkages to make corresponding rac-[Cu(L H)Cl ] complexes by late-stage ligand modification after coordination with the retention of coordination sphere. The generality of stereoselective self-assembly of koneramine complexes is shown by utilising a number of metal ions, anions, amines, alcohols and thiols with complete characterisations.
View Article and Find Full Text PDFJ Biomol Struct Dyn
December 2023
Department of Pharmaceutical Chemistry, Riphah International University, Islamabad, Pakistan.
A new class of azole-derived hemiaminal ethers is designed as acetylcholinesterase (AChE) inhibitors. The synthesized compounds exhibited remarkable inhibitory activity against acetylcholine. Chiral hemiaminals ( and ) based on ()-menthoxymethyl group exhibit excellent inhibition with IC values of 0.
View Article and Find Full Text PDFJ Org Chem
May 2022
Dipartimento di Chimica "U. Schiff", Università degli Studi di Firenze, Via della Lastruccia 13, Sesto Fiorentino (FI) 50019, Italy.
Six- and seven-membered ring-fused, functionalized cyclopentadienes can be obtained in moderate to excellent yields by a cascade process entailing the Au(I)-catalyzed propargyl Claisen rearrangement/Nazarov cyclization of propargyl vinyl ethers, the hetero-Diels-Alder reaction with dialkylazodicarboxylates, and the spontaneous conversion of cycloaddition products into cyclopentadienes by a highly regioselective cleavage of a C-N bond. Depending on the treatment of the crude reaction mixtures, two types of products can be obtained: cyclopentadienes with pendant hydrazine and aldehyde moieties that intramolecularly react to form hemiaminals are obtained in 43-52% overall yields when the crude reaction mixtures are left over KCO in a DCM solution. Instead, by reducing the aldehyde group just after addition of the heterodienophile, the regioselective C-N bond cleavage generates the corresponding cyclopentadienes bearing a hydrazine and an alcohol appendage in excellent yields (66-82%) over four steps, all in one pot.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
February 2022
Homogeneous Catalysis, Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr (Germany).
Strong and confined imidodiphosphorimidate (IDPi) catalysts enable highly enantioselective substitutions of cyclic, aliphatic hemiaminal ethers with enol silanes. 2-Substituted pyrrolidines, piperidines, and azepanes are obtained with high enantioselectivities, and the method displays a broad tolerance of various enol silane nucleophiles. Several natural products can be accessed using this methodology.
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