Hydroarylation of unsaturated carbon–carbon bonds in cross-conjugated enynones under the action of superacid CF<sub>3</sub>SO<sub>3</sub>H or acidic zeolite HUSY. Reaction mechanism and DFT study on cationic intermediate species
作者:Maiia I. Aleksandrova、Stanislav V. Lozovskiy、Steve Saulnier、Alexander A. Golovanov、Irina A. Boyarskaya、Aleksander V. Vasilyev
DOI:10.1039/c8ob01985a
日期:——
products of hydroarylation of the acetylene bond only,1,1,5-triarylpent-1,4-dien-3-ones, in yields up to 98%. These dienones add one more arene molecule to the double carbon–carbon bond in neat TfOH forming 1,1,5,5-tetraarylpent-1-en-3-ones in high yields. Cationic reaction intermediates have been studied by means of DFT calculations to elucidate plausible reaction mechanisms.
Brønsted Acid Promoted Cyclization of Cross-Conjugated Enynones into Dihydropyran-4-ones
作者:Steve Saulnier、Stanislav V. Lozovskiy、Alexander A. Golovanov、Alexander Yu. Ivanov、Aleksander V. Vasilyev
DOI:10.1002/ejoc.201700423
日期:2017.7.7
In triflic acid or sulfuric acid, diaryl-substituted cross-conjugated enynones undergo addition of the acid to the carbon–carbon triple bond to afford the corresponding vinyl triflates or sulfates. The vinyl triflates are stable under aqueous workup, whereas the vinyl sulfates are hydrolyzed to α,β-unsaturated 1,3-diketones (existing as conjugated enol forms). Extended reaction times lead to cyclization
practical Co-catalyzed cascade dehydrogenative Claisen condensation of secondaryalcohols with esters, facilitating the synthesis of a wide range of 3-hydroxy-prop-2-en-1-ones. We introduce a catalytic system based on novel and scalable indazole NNP-ligands coordinated to cobalt for efficient dehydrogenations of secondaryalcohols, and propose a plausible reaction mechanism supported by control experiments
The synthesis of numerous symmetric and non-symmetric curcumin(hetero) analoga (1-3) systematic variation of the conjugated chain and substituents is described. The structure of most compounds is confirmed by H-1-n.m.r.-spectroscopy. All compounds show E-configuration. Conjugation and tautomerism are discussed based on spectroscopic data.