Organic halides are important building blocks in synthesis, but their use in (photo)redox chemistry is limited by their low reduction potentials. Halogen-atom transfer remains the most reliable approach to exploit these substrates in radical processes despite its requirement for hazardous reagents and initiators such as tributyltin hydride. In this study, we demonstrate that α-aminoalkyl radicals, easily accessible from simple amines, promote the homolytic activation of carbon-halogen bonds with a reactivity profile mirroring that of classical tin radicals. This strategy conveniently engages alkyl and aryl halides in a wide range of redox transformations to construct sp-sp, sp-sp, and sp-sp carbon-carbon bonds under mild conditions with high chemoselectivity.
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http://dx.doi.org/10.1126/science.aba2419 | DOI Listing |
J Am Chem Soc
January 2025
The Warren and Katharine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Ni-catalyzed asymmetric reductive cross-coupling reactions provide rapid and modular access to enantioenriched building blocks from simple electrophile precursors. Reductive coupling reactions that can diverge through a common organometallic intermediate to two distinct families of enantioenriched products are particularly versatile but underdeveloped. Here, we describe the development of a bis(oxazoline) ligand that enables the desymmetrization of -anhydrides.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
Department of Chemistry, University of Tennessee, Knoxville, Tennessee 37916, United States.
Eukaryotic plasma membranes exhibit nanoscale lateral lipid heterogeneity, a feature that is thought to be central to their function. Studying these heterogeneities is challenging since few biophysical methods are capable of detecting domains at submicron length scales. We recently showed that cryogenic electron microscopy (cryo-EM) can directly image nanoscale liquid-liquid phase separation in extruded liposomes due to its ability to resolve the intrinsic thickness and electron density differences of ordered and disordered phases.
View Article and Find Full Text PDFChemistry
January 2025
Key Laboratory of Applied Chemistry of Chongqing Municipality, School of Chemistry and Chemical Engineering, Southwest University, 400715, Chongqing, China.
A visible-light-mediated strategy is reported for the direct synthesis of polychlorinated vicinal diaryl alkanes from aryl alkenes and chloroform. In this approach, two haloalkyl radicals generated from chloroform via halogen atom transfer (XAT) and direct single electron transfer (SET) within the same photoredox catalysis cycle enable the 1,4-dichloromethyldimerization of alkenes. Besides chloroform, this strategy is applicable to carbon tetrachloride, bromotrichloromethane, and α-bromo carboxylic esters, yielding corresponding 1,4-disubstituted vicinal diaryl alkanes.
View Article and Find Full Text PDFBeilstein J Org Chem
December 2024
Department of Chemical and Geological Sciences, University of Cagliari, S.S. 554, bivio per Sestu, 09042 Monserrato (CA), Italy.
The rising popularity of bioconjugate therapeutics has led to growing interest in late-stage functionalization (LSF) of peptide scaffolds. α,β-Unsaturated amino acids like dehydroalanine (Dha) derivatives have emerged as particularly useful structures, as the electron-deficient olefin moiety can engage in late-stage functionalization reactions, like a Giese-type reaction. Cheap and widely available building blocks like organohalides can be converted into alkyl radicals by means of photoinduced silane-mediated halogen-atom transfer (XAT) to offer a mild and straightforward methodology of alkylation.
View Article and Find Full Text PDFJ Org Chem
January 2025
Jiangxi Province Key Laboratory of Natural and Biomimetic Drugs Research, College of Chemistry and Materials, Jiangxi Normal University, Nanchang, Jiangxi 330022, P. R. China.
An efficient visible-light-induced radical carbon oximation of styrenes with 1-nitrosopyrrolidine and organic halides is developed. The reaction proceeds smoothly in the absence of a transition metal and a photocatalyst under mild conditions, producing a wide range of functionalized oximes in moderate to good yields. Mechanistic studies reveal that the reaction involves the generation of nucleophilic α-amino alkyl radicals and subsequent halogen atom transfer (XAT) with organic halides.
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