Chiral derivatizing agent
Configuration of secondary alcohols containing substituted-phenyl groups
Effect on δF across the space
Analytical Chemistry and Spectroscopy
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
The use of 2-fluoro-2-phenylacetic acid as a chiral derivatizing agent allowed the distinction, by means of fluorine NMR spectroscopy, of enantiomers of alcohols L1CH(OH)L2 converted into the diastereoisomeric esters PhCHFCO2CHL1L2. The δF(RR) and δF(RS) fluorine chemical shifts of diastereoisomeric esters obtained from series of alcohols containing a substituted-phenyl group (L1 or L2 = ZPh), and the ΔδF chemical shift differences, were linearly related to the Hammet σ parameter of Z. The ΔδF originates from the different electronic effects of L1 and L2 groups on the fluorine atom, through space, in a minor conformation. A classification of the ZPh effects on δF with respect to Ph is obtained. The configuration of substituted-phenyl secondary alcohols, ZPhCH(OH)L, can be determined with the aid of the δF values of esters formed with PhCHFCO2H if the configuration of the unsubstituted alcohol PhCH(OH)L is known.
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