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This paper reports a simple method of degradation of the readily available labdane group of diterpenoids to drimanic sesquiterpenes. The synthesis of (+)-drimane-8,11 -diol (5), the (+) and (±) forms of 14,15-bisnor-8a-hydroxylabd-11 (E) -en-13-one ( 7), (±)-8-epimeric hydroxy ,/3-unsaturated ketone (12), and (-)-drimenol (8) is described. Treatment of (+)-ambreinolide (1) with Pb(OAc)4 in boiling benzene for 120 hr gave compounds 2 (12%), 3 (22%), and 4 27%). Treatment of 1 with DDQ in boiling p-dioxane for 48 hr afforded 2 (40%). Ozonolysis of 2 in methylene chloride at -70°, followed by treatment with Red-Al, gave (+)-5 (85%). Oxidation of the latter with CrOg-pyridine gave aldehyde (+)-6 (50%). Treatment of (+)-6 with sodium diethyl 2-oxopropylphosphonate in THE gave (+)-7 (40%). A parallel series of reactions starting with (±)-ambreinolide ( 1) gave (±)-2, (±)-5, (±)-6, and (±)-7. Treatment of (+)-5 with AC2O overnight gave a monoacetate which was dehydrated with POClg-pyridine at 0-5°to give a mixture of isomeric acetates. Basic hydrolysis of the latter gave a mixture of alcohols 8 and 9. From this mixture (-)-dimenol (8) was isolated by preparative TLC. Treatment of (i)-drimenol (8) with mchloroperbenzoic acid in methylene chloride at 0-5°g ave a mixture of a and ß epoxides. Reduction of the ß epoxide with L1AIH4 in THE gave diol 10. Oxidation of 10 with CrOg-pyridine gave 11, which on treatment with sodium diethyl 2-oxopropylphosphonate in THE gave ketone 12 (30%).

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Neoline (C24H39NO6), mp 161 °, was first isolated from amorphous aconitine by Freudenberg and Rogers.1 Careful studies led Wiesner, et al.,2 to assign structure 1, with a C-l -hydroxyl, to the alkaloid. Marion, et al.,2 subsequently correlated neoline with chasmanine, an alkaloid re-ported4•5 to have structure 3, and, on this basis, assigned structure 4, with a C-l 0-hydroxyl, to neoline.

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