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An asymmetric intramolecular spiro-amination to high steric hindering -C-H bond of 1,3-dicarbonyl via nitrene transfer using inactive aryl azides has been carried out by developing a novel Cp*Ir(III)-SPDO (spiro-pyrrolidine oxazoline) catalyst, thereby enabling the first successful construction of structurally rigid spiro-quaternary indolinone cores with moderate to high yields and excellent enantioselectivities. DFT computations support the presence of double bridging H-F bonds between [SbF] and both the ligand and substrate, which favors the plane-differentiation of the enol π-bond for nitrenoid attacking. These findings open up numerous opportunities for the development of new asymmetric nitrene transfer systems.
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http://dx.doi.org/10.1021/jacs.4c05560 | DOI Listing |
J Org Chem
September 2025
Yunnan Key Laboratory of Modern Separation Analysis and Substance Transformation, College of Chemistry and Chemical Engineering, Yunnan Normal University, Kunming 650500, China.
The generation of α-imino metal carbenes from readily available alkynes via nitrene transfer has emerged as an important advancement in carbene chemistry, but current methodologies remain constrained to noble-metal catalysts. Additionally, the dearomatization involving α-imino metal carbenes has not been unexplored. In this study, we disclose a copper-catalyzed dearomatization reaction of azides with ynamide-phenol derivatives via α-imino copper carbenes.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
Department of Chemistry, Indian Institute of Engineering Science and Technology, Shibpur, Botanic Garden, Howrah, 711103, India.
Despite extensive studies of electrophilic copper-nitrenoid species in nitrene transfer chemistry, the formation and application of Cu-nitrene radicals remain elusive and underdeveloped. Nitrene radicals, being highly reactive, actively participate in radical-type amination reactions under mild conditions. Using a well-defined Cu(II)-catalyst [Cu(L)Cl] (1) bearing 2,6-bis(phenyldiazenyl)pyridine (L) as a ligand, the otherwise copper-stabilized electrophilic nitrenoid species has been transformed to a nitrene radical species via selective catalyst to nitrene single electron transfer.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2025
RWTH Aachen University, Institute of Organic Chemistry, Landoltweg 1, 52074, Aachen, Germany.
The selective incorporation of nitrogen into organic molecules remains a central challenge in modern synthetic chemistry, particularly when aiming to access complex, functionalized scaffolds under mild and sustainable conditions. In this report, we describe a photocatalytic method that employs hydroxylamine-derived nitrene precursors and unprotected sulfinamides under mild conditions, enabling efficient nitrene transfer without the need for stoichiometric amounts of an oxidant. The resulting unprotected sulfonimidamides serve not only as target compounds but also as versatile intermediates for further nitrene-transfer reactions, affording complex sulfur-nitrogen-rich frameworks.
View Article and Find Full Text PDFJ Am Chem Soc
August 2025
Department of Chemistry, Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India.
An iron-based metalloradical activation concept is developed for an intramolecular molecular rearrangement via ester migration and an allylic C(sp)-H amination using tetrazole as a nitrene precursor. It has been shown that an appropriate choice of catalyst can switch the chemoselectivity of a particular substrate from molecular rearrangement toward allylic C(sp)-H amination. The scope of the reactions has been demonstrated by the use of a wide number of tetrazoles and aryl azides.
View Article and Find Full Text PDFMolecules
July 2025
Department of Chemistry, Missouri University of Science and Technology, Rolla, MO 65409, USA.
A 12-membered pyridinophane scaffold containing two pyridine and two tertiary amine residues is examined as a prototype ligand (N4) for supporting nitrene transfer to olefins. The known [(N4)M(MeCN)] (M = Mn, Fe, Co, and Ni) and [(N4)Cu(MeCN)] cations are synthesized with the hexafluorophosphate counteranion. The aziridination of para-substituted styrenes with PhI=NTs (Ts = tosyl) in various solvents proved to be high yielding for the Cu(I) and Cu(II) reagents, in contrast to the modest efficacy of all other metals.
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