Reaction with a chiral nonracemic alcohol (R*OH, where R* is a
group containing a stereogenic center) generates a Mosher’s ester (42) that
can be analyzed for diastereomeric composition by 1H or 19F NMR, as well
as by chromatographic techniques.106 Alternatively, complexation with
lanthanide shift reagents allow the signals of the MTPA ester to be resolved
and used to determine enantiomeric composition.107 This nmr method, as
well as other related methods,108 are effective for determining the absolute
configuration of an alcohol of interest (R*OH).109 Two, of many other
reagents that have been developed to allow the enantiopurity of alcohols
and amines to be determined include 43 and 44. Chloromethyl lactam 43
reacts with R*OH or R*NHR (R*NH2),110 forming derivatives that allow
analysis by 1H NMR and 44 reacts with alkoxides (R*O)111 to form a
derivative that can be analyzed by 31P NMR. For a more detailed discussion
of methods to determine optical purity (see p. 179).
Reaction with a chiral nonracemic alcohol (R*OH, where R* is agroup containing a stereogenic center) generates a Mosher’s ester (42) thatcan be analyzed for diastereomeric composition by 1H or 19F NMR, as wellas by chromatographic techniques.106 Alternatively, complexation withlanthanide shift reagents allow the signals of the MTPA ester to be resolvedand used to determine enantiomeric composition.107 This nmr method, aswell as other related methods,108 are effective for determining the absoluteconfiguration of an alcohol of interest (R*OH).109 Two, of many otherreagents that have been developed to allow the enantiopurity of alcoholsand amines to be determined include 43 and 44. Chloromethyl lactam 43reacts with R*OH or R*NHR (R*NH2),110 forming derivatives that allowanalysis by 1H NMR and 44 reacts with alkoxides (R*O)111 to form aderivative that can be analyzed by 31P NMR. For a more detailed discussionof methods to determine optical purity (see p. 179).
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