Cu and Au Metal-Organic Frameworks Bridge the Gap between Homogeneous and Heterogeneous Catalysts for Alkene Cyclopropanation Reactions
作者:Avelino Corma、Marta Iglesias、Francesc X. Llabrés i Xamena、Félix Sánchez
DOI:10.1002/chem.201000278
日期:2010.8.23
The copper and gold metal–organicframeworks (MOFs) [Cu3(BTC)2(H2O)3]n, [Cu3(BTC)2] (BTC=benzene‐1,3,5‐tricarboxylate), and IRMOF‐3‐SI‐Au are active and reusable solid catalysts for the cyclopropanation of alkenes with high chemo‐ and diastereoselectivities. This type of material gives better results than previous solid catalysts while working together with the homogeneouscatalysts. These MOFs can help
A structurally characterized Rh(I) iminocarbene complex (N,C)Rh(CO)Cl is activated with AgOTf to act as a highly cis-selective catalyst for the cyclopropanation of substituted styrenes and other alkenes with ethyldiazoacetate (11 examples, 10−99% yield, up to >99% cis-selectivity).
Investigation of ligand steric effects on a highly cis-selective Rh(i) cyclopropanation catalyst
作者:Marianne Lenes Rosenberg、Eirin Langseth、Alexander Krivokapic、Nalinava Sen Gupta、Mats Tilset
DOI:10.1039/c1nj20343f
日期:——
Four new Rh(I) complexes bearing chelating imine-functionalized N-heterocyclic carbene ligands have been synthesized and characterized. The catalytic activity of these new Rh(I) complexes has been tested in the cyclopropanation reaction between ethyl diazoacetate and styrene. One of the new complexes, having ethyl groups on the ligand N-aryl ring, exhibited a reactivity and a cis-diastereoselectivity that were comparable to our previously reported Rh(I) cyclopropanation catalyst of this type, and a higher yield and cis-diastereoselectivity were obtained at lower catalyst loadings and higher temperatures. The other new Rh(I) complexes were found to be inferior to the previously reported Rh(I) cyclopropanation catalyst. The catalytic study gave important information about the effect that changing the steric requirements of the substituents at the ligand system has on the efficiency and cis-diastereoselectivity of the complexes as cyclopropanation catalysts.
A novel centrosymmetric porphyrazine (Pz) 1 decorated with pyrazino-dibenzo[ b,f ]azepine units have been prepared via Linstead macrocyclization re action of a dinitrile precursor. Accordingly, the peripheral azepine nitrogen offers a chemical h andle for subsequent functionalizations. Characterization of the metal complexes (MPzs = MetalPorphyrazines) of 1 was accomplished and good catalytic performances
Rhodium Acetate Dimer Immobilized in 1-Butyl-3-methylimidazolium Hexafluorophosphate Ionic Liquid: a Novel and Recyclable Catalytic System for the Cyclopropanation of Alkenes
作者:J. S. Yadav、B. V. S. Reddy、P. Narayana Reddy
DOI:10.1002/adsc.200303136
日期:2004.1
Alkenes undergo smooth cyclopropanation with ethyl diazoacetate using a catalytic amount of rhodium acetate dimer, Rh2(OAc)4, immobilized in the air- and moisture-stable 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, [bmim]PF6, to afford cyclopropanecarboxylates in excellent yields with high trans-selectivity. The recovery of the catalyst is facilitated by the hydrophobic nature of [bmim]PF6