Metal-Free Iodine-Catalyzed Oxidation of Ynamides and Diaryl Acetylenes into 1,2-Diketo Compounds
作者:Seung Woo Kim、Tae-Woong Um、Seunghoon Shin
DOI:10.1021/acs.joc.8b00484
日期:2018.4.20
Metal-free oxidation of ynamides is described, employing pyridine-N-oxides as oxidants under molecular iodine catalysis. In stark contrast to Brønsted acid catalysis, iodophilic activation of ynamides diverts the reaction manifold into a dioxygenation pathway. This oxidation is very rapid at room temperature with only 2.5 mol % I2. Furthermore, this protocol could be extended to nonactivated alkynes
Palladium-Catalyzed Oxygenative Cross-Coupling of Ynamides and Benzyl Bromides by Carbene Migratory Insertion
作者:Yunpeng Gao、Guojiao Wu、Qi Zhou、Jianbo Wang
DOI:10.1002/anie.201712795
日期:2018.3.1
A palladium‐catalyzed oxygenative cross‐coupling of ynamides and benzyl bromides has been developed. After subsequent hydrogenation, α,α‐disubstituted amide derivatives were obtained in good yields. Migratory insertion of α‐oxo palladium carbene species, generated by intermolecular oxidation, is proposed as the key step in this reaction. The study demonstrates the potential of ynamides to serve as
Nature of the Nucleophilic Oxygenation Reagent Is Key to Acid-Free Gold-Catalyzed Conversion of Terminal and Internal Alkynes to 1,2-Dicarbonyls
作者:Alexey Yu. Dubovtsev、Nikolay V. Shcherbakov、Dmitry V. Dar’in、Vadim Yu. Kukushkin
DOI:10.1021/acs.joc.9b02785
日期:2020.1.17
2,3-Dichloropyridine N-oxide, a novel oxygen transfer reagent, allows the conductance of the gold(I)-catalyzed oxidation of alkynes to 1,2-dicarbonyls in the absence of any acid additives and undermildconditions to furnish the target species, including those derivatized by highly acid-sensitive groups. The developed strategy is effective for a wide range of alkyne substrates such as terminal- and