glucoBox ligand—a new carbohydrate-based bis(oxazoline) ligand. Synthesis and first application
作者:Mustafa Irmak、Annika Groschner、Mike M. K. Boysen
DOI:10.1039/b612986b
日期:——
The synthesis of a new bis(oxazoline) ligand from D-glucosamine and its application in enantioselective copper(I) catalysed cyclopropanations of olefins is described.
描述了由D-葡萄糖胺合成新的双(恶唑啉)配体及其在对映选择性铜(I)催化的烯烃环丙烷化中的应用。
Chiral bipyridine–copper(II) complex. Crystal structure and catalytic activity in asymmetric cyclopropanation
作者:Hoi-Lun Kwong、Wing-Sze Lee、Hung-Foon Ng、Wing-Hong Chiu、Wing-Tak Wong
DOI:10.1039/a706754b
日期:——
A chiral bipyridineâcopper(II) complex has been prepared and its crystal structure determined. The structure involves a CuN2Cl2 compressed tetrahedral stereochemistry. Chiral bipyridine complexes of copper-(I) and -(II) triflate are active catalysts for asymmetric cyclopropanation of alkenes with enantiomeric excesses up to 92%.
The synthesis and characterisation of copper(I) complexes of chiral pyridine-containing macrocyclic ligands (Pc-L*) and their use as catalysts in asymmetriccyclopropanation reactions are reported. All ligands and metal complexes were fully characterised, including crystal structures of some species determined by X-ray diffraction on single crystals. This allowed characterising the very different conformations
A reusable, insoluble polymer-bound bis(oxazoline) (IPB-box) for highly enantioselective heterogeneous cyclopropanation reactionsElectronic supplementary information (ESI) available: experimental. See http://www.rsc.org/suppdata/cc/b3/b306483b/
A reusable, insoluble polystyrene-supported bis(oxazoline) was developed, affording e.e.s >90% in the heterogeneous enantioselective cyclopropanation of styrene and 1,1-disubstituted alkenes with ethyl diazoacetate.
A chiral nitrogen-tethered bis (imidazoline) ligand (Nb-imidazoline) was newly designed and synthesized in a divergent strategy. Thus, a single coupling reaction of primary amine with two molecules of chloromethylated imidazoline provided the Nb-imidazoline. The copper(II) triflate complex of Nb-imidazoline catalyzed a trans-selective cyclopropanation of styrene with ethyl diazoacetate to give the adduct in high chemical yield with good enantiomeric excess up to 83%.