α-Substituted alkylphosphonates and phosphates have broad utility in the pharmaceutical, agrochemical, and commodity chemical industries. Herein, we present the copper-catalyzed atom transfer radical addition (ATRA) of alkyl halides to alkenylphosphonates for the synthesis of α-halophosphonates enabled by 1,1'-azobis(cyclohexanecarbonitrile) (ACHN). Mechanistic investigations support that the diazo compound serves as an in situ reducing agent regenerating [Cu(I)] throughout the reaction and enabling high turnover numbers. Under the optimized conditions, a broad scope of radical precursors, including primary, secondary, and tertiary haloalkanes add to substituted vinylphosphonates in good to excellent yields. Product derivatization demonstrates the synthetic utility of the reaction.
Primary alkyl halides are poor coupling partners in most atom transfer radical addition (ATRA) reactions due to their propensity to undergo off-cycle radical termination pathways, which lead to catalyst deactivation. Herein, we overcome this challenge in the Cu-catalyzed ATRA reaction though the addition of 1,1'-azobis...
Gyeongmin K. Lee, Tam D. Ho, Jacob A. Utley et al.· Organic Letters· 0 citations
α‑Haloalkylboron compounds are valuable ambiphilic synthons, but the conventional ATRA reaction using vinyl‐Bpin often gives products that are unstable and difficult to isolate. In this study, we developed a copper‑catalyzed ATRA reaction using a sterically bulky protecting group, “OxB(oxazaborolidinone)”. OxB sterical...
Radical-mediated transition-metal-catalyzed C─H carbonylation represents a direct and powerful approach for the synthesis of carbonyl compounds; however, the stoichiometric oxidants typically required for hydrogen atom abstraction hamper the extensive application of these protocols and raise environmental concerns. In...
Cheng-Cheng Fan, Jia-Ning Wu, Peng Wang et al.· Angewandte Chemie· 0 citations
Existing approaches to sulfoximine N-alkylation rely on N-nucleophilic substitution or direct radical trapping at nitrogen, which are hampered by harsh conditions or restricted reaction modes. Herein, we report a distinct strategy for radical N-alkylation through a copper-catalyzed radical cascade. The transformation p...
Ze-Guo Fang, Di Yang, Han-Yang Zhang et al.· Organic and biomolecular che...· 0 citations
Herein, we report a one-step Pd(II)-catalyzed strategy for the synthesis of synthetically challenging and medicinally important functionalized dibenzotropone scaffolds from readily accessible o-alkynylaryl nitriles and electron-rich aryl boronic acids. The cascade process involves regioselective 1,2-syn-carbopalladatio...
Ayush Kumar, Sankar Sau, Amit Kumar· Organic Letters· 0 citations
A general method to generate α-alkoxyalkyl radicals from pinacol boronic ester precursors (R–Bpin) has been developed. These radical precursors are stable in air, easy to prepare, and readily accessible via Matteson homologation followed by a 1,2-metallate shift with a broad range of metal alkoxides. The key step is a...
E. André-Joyaux, Lise Benoist, Agathe Fayolle et al.· Organic Chemistry Frontiers· 0 citations
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