(Pentamethylcyclopentadienyl)Iridium Dichloride Dimer {[IrCp*Cl2]2}: A Novel Efficient Catalyst for the Cycloisomerizations of Homopropargylic Diols and N-Tethered Enynes
iridium dichloride dimer [IrCp*Cl2]2}-catalyzed hydroalkoxylation of bis-homopropargylicalcohols provides an efficient access to dioxabicyclo[2.2.1]ketals. The cycloisomerizations proceed under mild conditions, with low catalytic loadings and short reaction times. This new protocol involving an Ir(III) catalyst also promoted the cycloisomerization of nitrogen-tethered 1,6-enynes to give azabicyclo[4
The cyclopentadienyl (Cp) group is a very important ligand for many transition‐metal complexes which have been applied in catalysis. The availability of chiralcyclopentadienyl ligands (Cpx) lags behind other ligand classes, thus hampering the investigation of enantioselective processes. We report a library of chiral CpxIrIII complexes equipped with an atropchiral Cp scaffold. A robust complexation
环戊二烯基(Cp)基团是许多在催化中应用的过渡金属配合物的重要配体。手性环戊二烯基配体(Cp x)的可用性落后于其他配体类别,因此妨碍了对映选择性过程的研究。我们报告了配备手性Cp支架的手性Cp x Ir III复合物的库。强大的络合程序可为Cp x Ir III络合物可靠地提供可调节的抗衡离子。在概念验证的应用中,含碘化物对烯炔的环异构化反应具有很高的选择性。脱氢哌啶稠合的环丙烷产物以良好的产率和对映选择性形成。
Chiral Tetrafluorobenzobarrelene Ligands for the Rhodium-Catalyzed Asymmetric Cycloisomerization of Oxygen- and Nitrogen-Bridged 1,6-Enynes
The long and winding Rhoad: The asymmetriccycloisomerization of nitrogen‐ and oxygen‐bridged 1,6‐enynes proceeded in the presence of a cationic rhodium complex that was coordinated by PPh3 and a chiral diene ligand to afford high yields of chiral 3‐aza‐ and 3‐oxabicyclo[4.1.0]heptenes and high enantioselectivities. TS=4‐toluenesulfonyl, Tf=trifluoromethanesulfonyl.
Chiral Diene-Phosphine Tridentate Ligands for Rhodium-Catalyzed Asymmetric Cycloisomerization of 1,6-Enynes
作者:Takahiro Nishimura、Yuko Maeda、Tamio Hayashi
DOI:10.1021/ol2013236
日期:2011.7.15
Asymmetriccycloisomerization of nitrogen-bridged1,6-enynes proceeded in the presence of a cationic rhodium complex coordinated with a chiral diene/phosphine tridentate ligand to give high yields of chiral 3-azabicyclo[4.1.0]heptenes with high enantioselectivity.
Pd-Catalyzed Cycloisomerization of 4-Aza-1,6-enynes to 3-Aza-bicyclo[4.1.0]hept-2-enes
作者:Hye Mi Oh、Ji Eun Park、Jisu Kim、Ju Hyun Kim、Youn K. Kang、Young Keun Chung
DOI:10.1002/chem.201402087
日期:2014.6.25
A method for the synthesis of bicyclo[4.1.0]heptenesfrom 1,6‐enynes through Pd‐catalyzed cycloisomerization has been developed. N‐ and O‐tethered 1,6‐enynes were successfully transformed to their corresponding 3‐aza‐ and 3‐oxabicyclo[4.1.0]heptenes in reasonable‐to‐high yields using the catalysts [PdCl2(CH3CN)2]/P(OPh)3 or [Pd(maleimidate)2(PPh3)2] in toluene. The computational calculations using