Asymmetric Counteranion-Directed Transition-Metal Catalysis: Enantioselective Epoxidation of Alkenes with Manganese(III) Salen Phosphate Complexes
作者:Saihu Liao、Benjamin List
DOI:10.1002/anie.200905332
日期:2010.1.12
Paired up: A highly active and enantioselective ion‐pair epoxidationcatalyst, consisting of an achiral MnIII–salen complex and a chiral phosphate counteranion, mediates the epoxidization of a wide range of alkenes with high yields and enantioselectivities (see scheme). The unique role of the counteranion is to stabilize an enantiomorphic conformation of the cationic Mn catalyst.
配对:高活性和对映选择性离子对环氧化催化剂,由非手性Mn III -salen配合物和手性磷酸抗衡阴离子组成,可介导高产率和对映选择性的多种烯烃的环氧化。抗衡阴离子的独特作用是稳定阳离子Mn催化剂的对映体构象。
Synthesis of Some New Spiropyranoquinolines and Evaluation of Their Free Radical Scavenging Activity
作者:Vassiliki Panteleon、Ioannis K. Kostakis、Panagiotis Marakos、Nicole Pouli、Ioanna Andreadou
DOI:10.1248/cpb.57.446
日期:——
preparation of some new spiro-substituted 4-hydroxypyranoquinolinones and their corresponding dihydropyrano cis-diols is described. The freeradical scavenging activity of the compounds was determined by means of their interaction with the stablefreeradical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the superoxide anions generated by the enzymic xanthine-xanthine oxidase system. The spiroadamatylpyranoquinolinone