A copper-promoted divergent intermolecular [2 + ] heteroannulation of β-CF-1,3-enynes with alkyl azides via alkyl radical-driven HAT and radical substitution (C-C bond formation) to form four- to ten-membered saturated -heterocycles is developed. This method enables the aryl-induced or kinetically controlled site selective functionalization of the remote C(sp)-H bonds at positions 2, 3, 4, 5, 6, 7, or 8 toward the nitrogen atom through triplet nitrene formation, radical addition across the C═C bond, HAT and radical substitution cascades, and features a broad substrate scope, excellent site selectivity, and facile late-stage derivatization of bioactive molecules. Initial deuterium-labeling and control experiments shed light on the reaction mechanism via nitrene formation and HAT.
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http://dx.doi.org/10.1021/acs.orglett.3c04041 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Sichuan University, State Key Laboratory of Biotherapy, CHINA.
Herein we report a cobalt-catalyzed hydroglycosylation of terminal alkynes, employing bench-stable ortho-iodobiphenyl (oIB) substituted sulfides as glycosyl donors. This reaction occurs with high stereo- and regioselectivity to afford E-configured vinyl α-C-glycosides, a class of compounds nontrivial to access by previous methods. The use of a bis(oxazoline) ligand with bulky side chains is critical for the high selectivities observed.
View Article and Find Full Text PDFMetal oxides are promising catalysts for small molecule hydrogen chemistries, mediated by interfacial proton-coupled electron transfer (PCET) processes. Engineering the mechanism of PCET has been shown to control the selectivity of reduced products, providing an additional route for improving reductive catalysis with metal oxides. In this work, we present kinetic resolution of the rate determining proton-transfer step of PCET to a titanium-doped POV, TiVO(OCH) with 9,10-dihydrophenazine by monitoring the loss of the cationic radical intermediate using stopped-flow analysis.
View Article and Find Full Text PDFChem Sci
January 2025
Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong Wollongong New South Wales 2522 Australia
Although electrostatic catalysis can enhance the kinetics and selectivity of reactions to produce greener synthetic processes, the highly directional nature of electrostatic interactions has limited widespread application. In this study, the influence of oriented electric fields (OEF) on radical addition and atom abstraction reactions are systematically explored with ion-trap mass spectrometry using structurally diverse distonic radical ions that maintain spatially separated charge and radical moieties. When installed on rigid molecular scaffolds, charged functional groups lock the magnitude and orientation of the internal electric field with respect to the radical site, creating an OEF which tunes the reactivity across the set of gas-phase carbon-centred radical reactions.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu-632014, India.
A porphyrin comprising a carboxyl-functionalized pyridine moiety was synthesized and characterized using H NMR, C NMR, FT-IR, powder-XRD, BET, ICP-MS, SEM and EDAX. The proton level (H = 1.19) and energy band gap (1.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, Illinois 60439, USA.
Photosynthetic reaction center proteins (RCs) provide ideal model systems for studying quantum entanglement between multiple spins, a quantum mechanical phenomenon wherein the properties of the entangled particles become inherently correlated. Following light-generated sequential electron transfer, RCs generate spin-correlated radical pairs (SCRPs), also referred to as entangled spin qubit (radical) pairs (SQPs). Understanding and controlling coherence mechanisms in SCRP/SQPs is important for realizing practical uses of electron spin qubits in quantum sensing applications.
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