Nickel-Catalyzed, Carbonyl-Ene-Type Reactions: Selective for Alpha Olefins and More Efficient with Electron-Rich Aldehydes
作者:Chun-Yu Ho、Sze-Sze Ng、Timothy F. Jamison
DOI:10.1021/ja061471+
日期:2006.4.1
carbonyl-ene-type reactions, including those between alpha olefins and aromatic aldehydes. Catalyzed by nickel, these processes complement existing Lewis acid-catalyzed methods in several respects. Not only are monosubstituted alkenes, aromatic aldehydes, and tert-alkyl aldehydes effective substrates, but monosubstituted olefins also react faster than those that are more substituted, and large or electron-rich
Nickel-Catalyzed Coupling of Alkenes, Aldehydes, and Silyl Triflates
作者:Sze-Sze Ng、Chun-Yu Ho、Timothy F. Jamison
DOI:10.1021/ja062866w
日期:2006.9.1
two recently developed nickel-catalyzed coupling reactions of alkenes, aldehydes, and silyl triflates is presented. These reactions provide either allylic alcohol or homoallylic alcohol derivatives selectively, depending on the ligand employed. These processes are believed to be mechanistically distinct from Lewisacid-catalyzed carbonyl-ene reactions, and several lines of evidence supporting this hypothesis
inclination of other 17-electron metal carbonyl complexes to undergo associative ligand displacement reactions, it seems ironic that the incorporation of a pentadienyl ligand, which would be expected to promote associative attack via $ 73 coordination changes, should lead instead to a series of compounds for which much lower rates of substitution are observed and for which the substitutions also take place