Synthesis of Metal–(Pentadentate-Salen) Complexes: Asymmetric Epoxidation with Aqueous Hydrogen Peroxide and Asymmetric Cyclopropanation (salenH2:N,N′-bis(salicylidene)ethylene-1,2-diamine)
作者:Hiroaki Shitama、Tsutomu Katsuki
DOI:10.1002/chem.200601420
日期:2007.6.4
manganese(III) and cobalt(II) complexes, in which the fifth ligand is expected to intramolecularly coordinate to the metal center and exert a trans effect. Indeed, high enantioselectivity has been achieved in epoxidations using aqueous hydrogen peroxide as the terminal oxidant and in cyclopropanations with these complexes as catalysts. In general, metallosalen-catalyzed reactions have been carried out
Compounds containing oxazolidinone moiety and uses thereof
申请人:——
公开号:US20040039209A1
公开(公告)日:2004-02-26
A compound and method for producing an enantiomerically enriched epoxide from an olefin using a chiral ketone and an oxidizing agent is disclosed. In particular, the compound is of the formula: I wherein R
1
, R
2
, R
3
and R
4
are those defined herein.
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。
Enantioselective Epoxidation of Conjugated <i>cis</i>-Enynes by Chiral Dioxirane
作者:Christopher P. Burke、Yian Shi
DOI:10.1021/jo070205r
日期:2007.5.1
This paper describes a highly chemo- and enantioselectiveepoxidation of conjugated cis-enynes using readily available glucose-derived ketone 2 as catalyst and Oxone as oxidant to form cis-propargyl epoxides in high ee's. The interaction between the alkyne group of the substrate and the oxazolidinone moiety of the ketone catalyst as well as the interactions between the substituents on enynes and the
Optically Active<i>N</i>,<i>N</i>′-Bis(3-oxobutylidene)diaminatomanganese(III) Complexes as Novel and Efficient Catalysts for Aerobic Enantioselective Epoxidation of Simple Olefins
A novel manganese(III) complex having an opticallyactive N,N′-bis(3-oxobutylidene)diamine ligand with bulky substituents was prepared and characterized crystallographically. In the presence of a catalytic amount of the manganese(III) complex, unfunctionalizedolefins were oxygenated to give opticallyactive epoxides with molecular oxygen by the combined use of several aliphatic aldehydes. Cyclic and