2‐fluoro‐2‐phenylacetic acid. 4—Configuration of its esters with substituted‐phenyl alcohols by19F NMR
作者:
Michel Barrelle,
Sylvain Hamman,
期刊:
Magnetic Resonance in Chemistry
(WILEY Available online 1991)
卷期:
Volume 29,
issue 8
页码: 759-761
ISSN:0749-1581
年代: 1991
DOI:10.1002/mrc.1260290803
出版商: John Wiley&Sons, Ltd.
关键词: 2‐Fluoro‐2‐phenylacetic acid;Chiral derivatizing agent;Configuration of secondary alcohols containing substituted‐phenyl groups;Fluorine NMR;Effect on δF across the space
数据来源: WILEY
摘要:
AbstractThe 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)L2converted 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 (L1or 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 L1and L2groups 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
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