Chiral recognition rationale

Using a chiral recognition rationale, Plrkle, et fd (10) designed a chiral fluoroalcohollc bonded stationary phase which separates the enantiomers of sulfoxides, lactones, and derivatives of alcohols, amines, amino acids, hydroxy acids, and mercaptans. 

There is justifiable skepticism concerning the validity of any mechanism purporting to explain such small energy differences, despite a strong tendency among workers in the field to advance chiral recognition rationales, even when comparatively few data are available upon which to base such a rationale Typically, chromatographic separation of enantiomers in-... 

A completely different approach was pursued by Fuji and coworkers [14]. The enantiomeri-cally pure pyridine derivative 18 was prepared, the rationale being that the reduced steric hindrance in the proximity of the nitrogen nucleus should result in efficient catalytic turnover and that chiral recognition might be possible by remote asymmetric induction in a process similar to the induced fit mechanism in enzymes. When 18 was reacted with racemic 19b and isobutyric anhydride (l/ ,25)-19b was recovered with ee = 81% (71% conversion, 5 = 4.5,... 

This widely used rationale to explain the enantioselectivity of enzymes was suggested by A.G. Ogston [110]. Since chirality is a quality of space, a substrate must be positioned firmly in three dimensimis within the active site of an enzyme in order to ensure spatial recognition and to achieve a high degree of enantioselection. As a consequence, at least three different points of attachment of the substrate onto the active site are required. ... 

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