Up the Hill: Selective Double-Bond Isomerization of Terminal 1,3-Dienes towards Z-1,3-Dienes or 2Z,4E-Dienes
作者:Florian Pünner、Anastasia Schmidt、Gerhard Hilt
DOI:10.1002/anie.201107512
日期:2012.1.27
different cobalt catalyst systems led to the selectiveisomerization of 1,3‐dienes. In the case of the [CoBr2(py‐imine)]‐catalyzed reaction, the Z‐1,3‐diene was formed in a highly selective manner (see scheme). When the catalyst precursor [CoBr2(dpppMe2)] was applied, a double‐bond migration and selectiveisomerizationtowards the 2Z,4E‐configured 2,4‐dienes were observed
synthetic intermediates that possess strain energies exceeding those of saturated cyclopropanes by >10 kcal/mol. This report describes a catalytic reductive methylenecyclopropanation reaction of simple olefins, utilizing 1,1-dichloroalkenes as vinylidene precursors. The reaction is promoted by a dinuclear Ni catalyst, which is proposed to access Ni2(vinylidenoid) intermediates via C—Cl oxidative addition.
A New Ruthenium-Catalyzed Hydrogen-Transfer Reaction: Transformation of 3-Benzyl But-1-ynyl Ethers into 1,3-Dienes and Benzaldehyde
作者:Kuo-Liang Yeh、Bo Liu、Ching-Yu Lo、Heh-Lung Huang、Rai-Shung Liu
DOI:10.1021/ja012623y
日期:2002.6.1
We report a ruthenium-catalyzedreaction for various 3-benzyl but-1-ynyl ethers with suitable functionalities. Treatment of these substrates with TpRu(PPh3)(CH3CN)2PF6 (8.0 mol %) catalyst in 1,2-dichloroethane (80 degrees C, 12 h) afforded functionalized 1,3-dienes and benzyl aldehyde in good yields. This process is considered to be a tandem dealkoxylation and transfer hydrogenation. Deuterium-labeling