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Structural studies of four new sesquiterpenes, 3ß-angeloyloxy-6ß-(3-methylbutanoyloxy)- and 3ß,6ß-bis(angeloyloxy)furanoeremophilan-14-als and 3ß-angeloyloxy-6ß-(3-methylbutanoyloxy)- and 3ß-angeloyloxy-6ß-(3-methylpentanoyloxy)furanoeremophilan-14-oic acids, together with 3ß,6ß-bis(angeloyloxy)furanoeremophilan- 14-oic acid from Syneilesis palmata(Thunb.) Maxim, are described.

Dry ozonation of friedelane afforded 18ß,19ß-epoxyfriedelane, 19-oxofriedelane, 16-oxofriedelane, 21-oxofriedelane, friedelin, and a new compound, 15-oxofriedelane. Friedelin, on dry ozonation, gave 3,16-dioxofriedelane, 3,19-dioxofriedelane, and new compounds, 18ß,19ß-epoxyfriedelan-3-one and 3,15-dioxofriedelane. It was shown that the oxidation occurred at D and E rings regioselectively in the dry ozonation.

Three new furanosesquiterpenes have been isolated from Ligularia japonicaLESS., and their structures including absolute configurations have been determined as furanoeremophilane-6β-diol (1), 10β-hydroxyfu-ranoeremophilan-6β-yl 2′ξ-methylbutanoate (2), and 10β-hydroxy-6β-methoxyfuranoeremophilane (3).

4,6-Dimethylcoumarin (3) was converted to an enantiomer (1b) of farfugin A, viaa levorotatory carboxylic acid (5b). This led to the absolute configuration (1a) for farfugin A.

(±)-14-Norfuranoeudesmane-4,6-dione, (±)-furanoeremophilane-3,6-dione, and (±)-furanoeremophilan-14, 6a-olide were synthesized by a route involving alkylation of a dianion obtained from 2,4-dimethyl-3-furoic acid.

Pulegone was transformed into isopulegone enol acetate or isopulegone ethylene acetal, which was treated with m-chloroperbenzoic acid and then with acid to give menthofuran. Fukinone was converted into furanoeremophilane by the same procedure.