64. Synthese und Charakterisierung der 8 isomeren, im Ring B mono- bzw. dihydroxylierten Royleanone

Article abstract of DOI:10.1002/hlca.19810640304

The partial syntheses of 6α,7α-dihydroxyroyleanone (6a), 6α,7β-dihydroxyroyleanone (7a) and 6β,7β-dihydroxyroyleanone (9a) are described.Thus, all in ring B mono- and dihydroxylated royleanones are now known (see <2-11>), being fully characterized by extensive spectroscopic, chiroptic and chromatographic (HPLC.) methods.An opening of the epoxyroyleanone 11a yields cis- and trans-diols together with their corresponding mono- and di-O-acetyl derivatives.We postulate a reversible addition of the acetate ion at C(8) of the quinone system, followed by a neighbouring group participation of this O-acetyl group.