Absolute Structures of Two New C13-Norisoprenoids from Apollonias barbujana

Two new C13-norisoprenoid compounds, (3S,5R,6S,9R)-3,6-dihydroxy-5,6-dihydro-β-ionol (1) and (3S,4S,5S,6S,9S)-3,4-dihydroxy-5,6-dihydro-β-ionol (2), were isolated from the leaves of Apollonias barbujana. The absolute structures were determined by spectroscopic methods and chemical transformations. (3S,4S,5S,6S,9R)-3,4-Dihydroxy-5,6-dihydro-β-ionol (3) was also isolated, the structure of which has been determined by X-ray analysis and whose 1H-NMR, 13C-NMR, and MS data are reported herein.