cyclization of N-acetyl enamines and intermolecular cyclocondensation of enamines and nitriles was investigated. The reaction was performed under mild conditions and gave oxazoles and imidazoles, respectively, in moderate to excellent yields. This transformation exhibits good reactivity, selectivity and functional group tolerance. The selectivity of the intra- or intermolecular reaction is dependent on the
Supramolecular chiral phosphorous ligands based on a [2]pseudorotaxane complex for asymmetric hydrogenation
作者:Yong Li、Yu Feng、Yan-Mei He、Fei Chen、Jie Pan、Qing-Hua Fan
DOI:10.1016/j.tetlet.2008.03.039
日期:2008.4
A new type of supramolecular chiral phosphorus-based ligands was prepared from easily available monodentate ligands through complexationbetween dibenzylammonium salt and dibenzo[24]crown-8 macrocycle. Rhodium complexes with these supramolecular ligands were prepared, and the supramolecular bidentate ligand-containing catalyst has demonstrated better catalytic activity for all substrates, and higher