STUDIES ON CYCLITOLS .13. SYNTHESIS AND STEREOCHEMISTRY OF CYCLOPENTANETRIOLS AND RELATES EPOXYCYCLANOLS

Derivatives of the three diastereomeric 1,2,3-cyclopentanetriols, and the three diastereomeric 1,2,4-cyclopentanetriols have been synthesized via reaction sequences starting with 2-cyclopentenol, 3-cyclopentenol, and various cyclopentenediols. All four isopropylidene derivatives, three mono-O-benzoylisopropylidene acetals, and five tribenzoates have been prepared. The four 1,2-anhydrocyclo-pentanetriols, their acetylated derivatives, and several other substituted cyclopentane epoxides were also prepared. The kinetics of the acid-catalyzed hydrolysis of several substituted epoxides were studied, in order to assess the factors affecting such reactions. The presence or absence of intramolecular H-bonds, determined by IR spectroscopy, was useful in assigning configurations for some of the compounds. For a number of monosubstituted cyclopentane epoxides, the frequency of the IR absorption band near 840 cm-1, which is characteristic of the oxirane ring, is correlated with the position and orientation of the substituent. The CBr stretching frequencies in several bromoepoxides have been assigned and correlated with the axial or equatorial orientation of the bromo group. © 1969.