16159-03-8Relevant academic research and scientific papers
Development and Mechanistic Studies of the Iridium-Catalyzed C?H Alkenylation of Enamides with Vinyl Acetates: A Versatile Approach for Ketone Functionalization
Zhou, Bo,Qi, Xiaotian,Liu, Peng,Dong, Guangbin
supporting information, p. 20926 - 20934 (2021/08/18)
Ketone functionalization is a cornerstone of organic synthesis. Herein, we describe the development of an intermolecular C?H alkenylation of enamides with the feedstock chemical vinyl acetate to access diverse functionalized ketones. Enamides derived from various cyclic and acyclic ketones reacted efficiently, and a number of sensitive functional groups were tolerated. In this iridium-catalyzed transformation, two structurally and electronically similar alkenes—enamide and vinyl acetate—underwent selective cross-coupling through C?H activation. No reaction partner was used in large excess. The reaction is also pH- and redox-neutral with HOAc as the only stoichiometric by-product. Detailed experimental and computational studies revealed a reaction mechanism involving 1,2-Ir-C migratory insertion followed by syn-β-acetoxy elimination, which is different from that of previous vinyl acetate mediated C?H activation reactions. Finally, the alkenylation product can serve as a versatile intermediate to deliver a variety of structurally modified ketones.
Novel self-coupling reaction of cyclic ketones under a high-pressure mercury lamp
Ji, Shun-Jun,Matsushita, Masatoshi,Takahashi, T. Tomoyoshi,Horiuchi, C. Akira
, p. 6791 - 6794 (2007/10/03)
A novel self-coupling reaction in alcohol or hexane-water of cycloalkanone (cycloheptanone, cyclooctanone, and cyclododecanone) with irradiation under a high-pressure mercury lamp yielded the corresponding pinacol-type compound in good yields. In the case of cyclohexanone, 2-methyl-, 2-phenyl-, 4-methylcyclohexanone, 5α- and 5β-cholestan-3-one, the pinacol derivatives were not obtained and the dimethyl acetals were given.
STEREOCHIMIE-LVII ETUDE STEREOCHIMIQUE ET CINETIQUE DE LA BROMATION D'ESTERS ET D'ETHERS ENOLIQUES STEROIDIQUES
Calvet, Alain,Jozefowitz, Marcel,Levisalles, Jacques
, p. 103 - 115 (2007/10/02)
Absolute rates of bromination were measured for two series of derivatives of steroidal ketones 3, enol acetates 1 and enol methyl ether 2.Axial substituents exhibited a large effect on rates, which increased by 15,000 fold on going from (X=CH3; Y=CN) to (X=Y=H).From the bromide ion effect it was concluded that the first step (formation of an intermediate bromonium ion) was reversible and that the second step (formation of haloketones 4 or 5 or of haloacetals 8 or 9) was slow compared to the first step.The intermediate was concluded to be a highly unsymmetrical bromonium ion rather than a plain oxocarbenium ion.
