Studies on the Constituents of the Plants of Illicium Species. III. Structure Elucidations of Novel Phytoquinoids, Illicinones and Illifunones from Illicium tashiroi MAXIM. and I. arborescens HAYATA

Abstract

Chemical constituents of the leaves of Illicium tashiroi and I. arborescens (Illiciaceae) were examined. Novel phytoquinoids, (+)-illicinone-A (1a), -B (2a), -C (3a), and -D (4a), and illifunone-A (5a) and -B (5b) were isolated from I. tashiroi, and characterized. As constituents of I. arborescens, enantiomers (1b and 2b) of (+)-illicinone-A (1a) and -B (2a), and diastereoisomers (2c, 3b, 4b, and 4c) of (+)-illicinone-B (2a), -C (3a), and -D (4a) were characterized. The absolute stereochemistry of (-)-illicinone-A was established by analysis of the circular dichroism (CD) spectra of the α-hydroxy ketones (15 and 16) derived from 1b. The stereochemistries of other illicinones and illifunones deduced from the chemical and/or biogenetic correlations.