Do the terms "% ee" and "% de" make sense as expressions of stereoisomer composition or stereoselectivity?

被引:121
作者
Gawley, RE [1 ]
机构
[1] Univ Arkansas, Dept Chem & Biochem, Fayetteville, AR 72701 USA
关键词
D O I
10.1021/jo052554w
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Enantiomeric excess (ee) was originally defined as a term to describe enantiomeric composition and was equated with optical purity. More recently, ee and its Cousin de (diastereomeric excess) have been used (inappropriately) to quantitate stereoselectivity. The quantity ee has been used in equations describing processes Such as kinetic resolutions, but these equations are unnecessarily complex because it is enantiomer ratio, not enantiomeric excess, that directly reflects relative rates. A historical summary of: the development of ee as an expression of enantiomer composition and enantioselectivity is presented, along with new equations and figures defining and illustrating the stereoselectivity factor, s, kinetic resolutions versus % conversion, and linear correlations of enantiomer composition of catalysts and products. New figures illustrating nonlinear effects versus enaniomer composition are presented, and Kagan's index of amplification for positive nonlinear effects is discussed and illustrated. A case is made for the discontinuance of ee and de as descriptors of stereoisomer composition and stereoselectivity.
引用
收藏
页码:2411 / 2416
页数:6
相关论文
共 31 条
[1]  
[Anonymous], 1978, Top. Stereochem
[2]   Dynamic thermodynamic resolution: Control of enantioselectivity through diastereomeric equilibration [J].
Beak, P ;
Anderson, DR ;
Curtis, MD ;
Laumer, JM ;
Pippel, DJ ;
Weisenburger, GA .
ACCOUNTS OF CHEMICAL RESEARCH, 2000, 33 (10) :715-727
[3]  
Beesley T. E., 1998, SEPAR SCI S
[4]  
Fenwick D. R., 1999, Top. Stereochem
[5]   Emerging methods for the rapid determination of enantiomeric excess [J].
Finn, MG .
CHIRALITY, 2002, 14 (07) :534-540
[6]  
FRASER RR, 1983, ASYMMETRIC SYNTHESIS, V1, P173
[7]   Chiral organolithium complexes: The structure of beta-lithiated beta-phenylcarboxamides and the mechanism of asymmetric substitution in the presence of (-)-sparteine [J].
Gallagher, DJ ;
Du, H ;
Long, SA ;
Beak, P .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1996, 118 (46) :11391-11398
[8]   On diastereomeric perturbations [J].
Girard, C ;
Kagan, HB .
CANADIAN JOURNAL OF CHEMISTRY, 2000, 78 (06) :816-828
[9]   NONLINEAR EFFECTS IN ASYMMETRIC CATALYSIS [J].
GUILLANEUX, D ;
ZHAO, SH ;
SAMUEL, O ;
RAINFORD, D ;
KAGAN, HB .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1994, 116 (21) :9430-9439
[10]   METHOD FOR OBTAINING AN ENANTIOMER CONTAINING LESS THAN 0.1 PERCENT OF ITS ANTIPODE - DETERMINATION OF ITS MAXIMUM ROTATORY POWER [J].
HOREAU, A .
TETRAHEDRON, 1975, 31 (10) :1307-1309