Lewis Basicity Modulation of N-Heterocycles: A Key for Successful Cross-Metathesis
摘要:
Cross-metathesis involving N-heteroaromatic olefinic dervatives is disclosed. The introduction of an appropriate substitutent on the heteroaromatic ring decreases the lewis basicity of the nitrogen atom, thus preventing the deactivation of the ruthenium-centered catalyst. The reaction is quite general in terms of both N-heterocycles and olefinic partners.
Nickel-Catalyzed Hydroarylation of in Situ Generated 1,3-Dienes with Arylboronic Acids Using a Secondary Homoallyl Carbonate as a Surrogate for the 1,3-Diene and Hydride Source
The nickel-catalyzedhydroarylation of 1,3-dienes with arylboronicacidsusing a secondaryhomoallylcarbonate as a surrogate for the 1,3-diene and hydridesource has been developed. The synthetic strategy allowed an efficient access to a wide array of hydroarylation products in high yields with high functional group compatibility without the use of an external hydridesource. Mechanistic experiments
Preparation of Allyltin Reagents Grafted on Solid Support: Clean and Easily Recyclable Reagents for Allylation of Aldehydes
作者:Jean-Mathieu Chrétien、Françoise Zammattio、Delphine Gauthier、Erwan Le Grognec、Michaël Paris、Jean-Paul Quintard
DOI:10.1002/chem.200501595
日期:2006.9.6
The preparation of polymer-supported allyltin reagents was shown to be possible for both unfunctionalized and functionalized allyl units. These reagents were treated with aldehydes in the presence of cerium(III) or indium(III) salts to afford high yields of homoallylic alcohols, practically uncontaminated with organotin residues (less than 5 ppm). Some mechanism aspects are briefly discussed and the
Enantioselective reduction of heteroaromatic β,γ-unsaturated ketones was found to be an efficient and convenient alternative to the allylboration of corresponding aldehydes. This new method was used for the formal asymmetric synthesis of SIB-1508Y 2.
Cross-metathesis involving N-heteroaromatic olefinic dervatives is disclosed. The introduction of an appropriate substitutent on the heteroaromatic ring decreases the lewis basicity of the nitrogen atom, thus preventing the deactivation of the ruthenium-centered catalyst. The reaction is quite general in terms of both N-heterocycles and olefinic partners.