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1. Ag ^II ‐Mediated Electrocatalytic Ambient CH ₄ Functionalization Inspired by HSAB Theory

   https://doi.org/10.1002/anie.202104217  

   Xiang, Danlei; Iñiguez, Jesus A.; Deng, Jiao; Guan, Xun; Martinez, Antonio; Liu, Chong (July 2021, Angewandte Chemie International Edition)

   Abstract Although most class (b) transition metals have been studied in regard to CH₄activation, divalent silver (Ag^II), possibly owing to its reactive nature, is the only class (b) high‐valent transition metal center that is not yet reported to exhibit reactivities towards CH₄activation. We now report that electrochemically generated Ag^IImetalloradical readily functionalizes CH₄into methyl bisulfate (CH₃OSO₃H) at ambient conditions in 98 % H₂SO₄. Mechanistic investigation experimentally unveils a low activation energy of 13.1 kcal mol⁻¹, a high pseudo‐first‐order rate constant of CH₄activation up to 2.8×10³ h⁻¹at room temperature and a CH₄pressure of 85 psi, and two competing reaction pathways preferable towards CH₄activation over solvent oxidation. Reaction kinetic data suggest a Faradaic efficiency exceeding 99 % beyond 180 psi CH₄at room temperature for potential chemical production from widely distributed natural gas resources with minimal infrastructure reliance. 

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2. Pd(II)-Catalyzed Synthesis of Benzocyclobutenes by β-Methylene-Selective C(sp ³ )–H Arylation with a Transient Directing Group

   https://doi.org/10.1021/jacs.1c09368  

   Provencher, Philip A.; Hoskin, John F.; Wong, Jonathan J.; Chen, Xiangyang; Yu, Jin-Quan; Houk, K. N.; Sorensen, Erik J. (December 2021, Journal of the American Chemical Society)
3. Electronic Structure of Three-Coordinate Fe ^II and Co ^II β-Diketiminate Complexes

   https://doi.org/10.1021/acs.inorgchem.3c03388  

   Nagelski, Alexandra L; Ozerov, Mykhaylo; Fataftah, Majed S; Krzystek, J; Greer, Samuel M; Holland, Patrick L; Telser, Joshua (March 2024, Inorganic Chemistry)
4. Synthesis of Oxazoline and Oxazole Derivatives by Hypervalent-Iodine-Mediated Oxidative Cycloaddition Reactions

   https://doi.org/10.1055/s-0040-1707122  

   Yoshimura, Akira; Saito, Akio; Yusubov, Mekhman S.; Zhdankin, Viktor V. (August 2020, Synthesis)

   null (Ed.)

   Organohypervalent iodine reagents are widely used for the preparation of various oxazolines, oxazoles, isoxazolines, and isoxazoles. In the formation of these heterocyclic compounds, hypervalent iodine species can serve as the activating reagents for various substrates, as well as the heteroatom donor reagents. In recent research, both chemical and electrochemical approaches toward generation of hypervalent iodine species have been utilized. The in situ generated active species can react with appropriate substrates to give the corresponding heterocyclic products. In this short review, we summarize the hypervalent-iodine­-mediated preparation of oxazolines, oxazoles, isoxazolines, and isoxazoles starting from various substrates. 1 Introduction 2 Synthesis of Oxazolines 3 Synthesis of Oxazoles 4 Synthesis of Isoxazolines 5 Synthesis of Isoxazoles 6 Conclusion 

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5. Umpolung Synthesis of Pyridyl Ethers by Bi ^V ‐Mediated O‐Arylation of Pyridones

   https://doi.org/10.1002/anie.202212873  

   Ruffell, Katie; Gallegos, Liliana C.; Ling, Kenneth B.; Paton, Robert S.; Ball, Liam T. (November 2022, Angewandte Chemie International Edition)

   Abstract We report that O‐selective arylation of 2‐ and 4‐pyridones with arylboronic acids is affected by a modular, bismacycle‐based system. The utility of this umpolung approach to pyridyl ethers, which is complementary to conventional methods based on S_NAr or cross‐coupling, is demonstrated through the concise synthesis of Ki6783 and picolinafen, and the formal synthesis of cabozantib and golvatinib. Computational investigations reveal that arylation proceeds in a concerted fashion via a 5‐membered transition state. The kinetically‐controlled regioselectivity for O‐arylation—which is reversed relative to previous Bi^V‐mediated pyridone arylations—is attributed primarily to the geometric constraints imposed by the bismacyclic scaffold. 

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