The first example of salan-vanadium catalyzed enantioselective ring-opening of meso-epoxides has been reported, which furnished β-hydroxy sulfides in good yields and moderate enantioselectivities.
Chiral Scandium-Catalysed Enantioselective Ring-Opening ofmeso-Epoxides with N-Heterocycle, Alcohol and Thiol Derivatives in Water
作者:Marine Boudou、Chikako Ogawa、Shū Kobayashi
DOI:10.1002/adsc.200600290
日期:2006.12
of Sc(OSO3C12H25)3 and a chiral bipyridine ligand, asymmetric ring-opening of meso-epoxides with aromatic N-heterocycles, an alcohol and thiols proceeded smoothly to afford the corresponding products in moderate to good yields (34–85 %) with high to excellent enantioselectivities (74–96 % ee). Water was used as the sole and essential solvent in these important enantioselective transformations.
在催化量的Sc(OSO 3 C 12 H 25)3和手性联吡啶配体存在下,内消旋环氧与芳族N杂环,醇和硫醇的不对称开环顺利进行,得到适度的相应产物到良好的对映选择性(74–96%ee)的高收率(34–85%)。在这些重要的对映选择性转化中,水被用作唯一的必需溶剂。
Indium–bipyridine-catalyzed, enantioselective thiolysis of meso-epoxides
The indiumâbipyridine-catalyzed, enantioselective ring-opening of meso-epoxides with aliphatic and aromatic thiols furnished 1,2-mercapto alcohols in good yields and excellent enantioselectivities; the crystal structure of the chiral catalyst reveals a pentagonal-bipyramidal coordination geometry around the indium center.
Chiral Scandium-catalyzed Highly Stereoselective Ring-opening of<i>meso</i>-Epoxides with Thiols
作者:Chikako Ogawa、Naiwei Wang、Shu Kobayashi
DOI:10.1246/cl.2007.34
日期:2007.1
The desymmetrization of meso-epoxides with thiols proceeded smoothly in dichloromethane or dichloroethane in the presence of a catalytic amount of a chiral scandium complex consisting of Sc(OTf)3 and chiral bipyridine 1, to afford the corresponding sulfides in high yields with high enantioselectivities.
The enantioselective ring-openingreaction of meso-epoxides with arylthiolscatalyzed by a chiral heterobimetallic Ti–Ga–Salen complex was realized, and the 1,2-mercapto alcohols were obtained in good yields and moderate to high enantioselectivities (up to 92% ee). A strong synergistic cooperation between different Lewis acids in the system was exhibited in the catalytic process.