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
Gold(I)-Catalyzed Diastereoselective Hydroacylation of Terminal Alkynes with Glyoxals
作者:Shuai Shi、Tao Wang、Vanessa Weingand、Matthias Rudolph、A. Stephen K. Hashmi
DOI:10.1002/anie.201307685
日期:2014.1.20
The reaction of an α‐ketoaldehyde and a terminalalkyne in the presence of piperidine and a catalytic amount of AuCl delivers 1,2‐dicarbonyl‐3‐enes, products of the formal hydroacylation of the triple bond. The scope of the method is broad; different aryl substituents on the dicarbonyl unit and on the alkyne are well tolerated. The products can be transformed selectively into vinylquinoxalines. Mechanistic
Rhodium(I)-Catalyzed Decarbonylative Aerobic Oxidation of Cyclic α-Diketones: A Regioselective Single Carbon Extrusion Strategy
作者:Gangadhararao Golime、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.7b03837
日期:2018.2.16
rhodium-catalyzed decarbonylative aerobic oxidation of cyclic α-diketones has been developed for the first time, where the regioselective formations of α-pyrones and isocoumarins have been achieved. The current decarbonylative aerobic oxidation pathway proceeds via the C–C bond cleavage followed by a C–O bond formation, representing a biomimetic oxidation approach to unsaturated six-membered cyclic
Synthesis of Ketones by C−H Functionalization of Aldehydes with Boronic Acids under Transition‐Metal‐Free Conditions
作者:Silvia Roscales、Aurelio G. Csáky
DOI:10.1002/anie.202015835
日期:2021.4.12
A method for the synthesis of ketones from aldehydes and boronic acids via a transition‐metal‐free C−H functionalization reaction is reported. The method employs nitrosobenzene as a reagent to drive the simultaneous activation of the boronic acid as a boronate and the activation of the C−Hbond of the aldehyde as an iminium species that triggers the key C−C bond‐forming step via an intramolecular migration
An efficient one-step synthesis of 2-acylquinolines using a copper-catalyzed tandem reaction of 2-ethynylanilines with glyoxals in the presence of piperidine has been developed. This new protocol successfully avoids multi-step operation and the use of highly toxic cyanides required in traditional methods, and provides a practical tool for synthetic and pharmaceutical chemists. Various 2-acylquinolines