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Determination of the Absolute Configuration and Enantiomeric Purity of Allylic and Acetylenic Alcohols

1991; Oxford University Press; Volume: 64; Issue: 11 Linguagem: Inglês

10.1246/bcsj.64.3390

1348-0634

Fujiko Yasuhara, Shozo Yamaguchi, Masayuki Takeda,

Metabolomics and Mass Spectrometry Studies

Abstract The relative magnitude of steric bulk of saturated vs. unsaturated substituents in the title compounds has been estimated by a lanthanoid induced shift (LIS) study of these (R)-(+)-α-methoxy-α-(trifluoromethyl)phenylacetate esters [(R)-(+)-MTPA esters] by 1H NMR spectroscopy: CH2=C(Me)−>Pentyl>n−Pr>Et\simeqCH2=CH−>Me>CH≡C−;Ph>Cyclohexyl These results allow the assignment of the absolute configurations of both cyclic and acyclic unsaturated alcohols. Furthermore, the relative intensity of well-separated OMe signals for those diastereomeric MTPA esters can be used for the determination of the %ee of the original alcohols.