Directα-alkylation of carbonylcompounds represents a fundamental bond forming transformation in organic synthesis. We report the first ketone-alkylation using olefins and alcohols as simple alkylating agents catalyzed by graphene oxide. Extensive studies of the graphene surface suggest a pathway involving dual activation of both coupling partners. Notably, we show that polar functional groups have
Generation and reactivity of the acetylacetonyl radical
作者:Yuan L. Chow、Gonzalo E. Buono-Core
DOI:10.1021/ja00377a060
日期:1982.6
ticularly important in regions of incipient bonding of the localized orbitals containing the unpaired electrons, Le., when they are directed toward one another and not too far away. It is possible to view the calculated energy change on going from gauche to cyclobutane as arising from a competition between the stabilizing effect of bond formation and the destabilizing effect of eclipsing interactions
HY zeolite-supported Au clusters ((AuHY)-H-0) prepared by deposition-precipitation method, well characterized by XANES. EXAFS, and NH3- and acetyl acetone-adsorption IR, were tested for addition of acetyl acetone to alkenes. (AuHY)-H-0 showed higher selectivity to the addition product than HY zeolite-supported Au(OH)(3) and Au clusters supported on NH4+-exchanged Y zeolite, Al2O3, MgO, SiO2, and TiO2. Studies on the effect of Au oxidation state, Au cluster size and Bronsted acidity of zeolite on the catalytic showed that co-presence of metallic Au with smaller cluster size and the acidic OH groups of the zeolite was necessary to the selective formation of the addition product. Cooperation mechanism of the Bronsted acid sites of the zeolite and Au clusters is proposed. (C) 2011 Elsevier B.V. All rights reserved.
Nucleophilic Substitution Reactions of Alcohols with Use of Montmorillonite Catalysts as Solid Brønsted Acids
a variety of alcohols with anilines, because the unique acidity of the H-mont catalyst effectively prevents the neutralization by the basic anilines. In addition, amides, indoles, 1,3-dicarbonyl compounds, and allylsilane act as nucleophiles for the H-mont-catalyzed substitutions of alcohols, which allowed efficient formation of various C−N and C−C bonds. The solid H-mont was reusable without any appreciable