Studies on the Terpenoids and Related Alicyclic Compounds. XXVI. Total Syntheses of highly Oxygenated Furanoeremophilanes. : (±)-6β-Hydroxy-1,10-dehydrofuranoeremophilan-9-one, (±)-Decompositin, (±)-Dihydrodecompositin, (±)-Adenostylone, (±)-3β, 6β-Diprop

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The total syntheses of several highly oxygenated, 1,10-dehydrofuranoeremophilanes [(±)-6β-hydroxy-1,10-dehydrofuranoeremophilan-9-one (1a), (±)-decompositin (1b), (±)-dihydrodecompositin (3), (±)-adenostylone (1c), (±)-3β, 6β-dipropionyleuryopsin-9-one (2b)] and polyoxy compounds [(±)-3β, 6β-dihydroxy-10βH-furanoeremophilan-9-one (4), (±)-3β, 6β-dihydroxy-10αH-furanoeremophilan-9-one (5), and 3β-acetoxy-6β-isobutyroxy-furanoeremophilan-9-one (28b)] from a bicyclic enone (6a) are described. Treatment of 10α-hydroxy-6,9-dioxo compounds (8a, 18 and 23) with SOCl_2-pyridine gave the corresponding 1,10-dehydro-6,9-dioxo compounds (11,20 and 24,respectively). NaBH_4 reduction of 11,20 and 24 afforded the 6β-hydroxy derivatives (12a, 1a and 2a, respectively) regio- and stereoselectively. (±)-1a was converted into (±)-1b, (±)-1c, and (±)-3. (±)-2a was also converted into (±)-2b. Catalytic reduction of 12a with H_2/Pd gave the 10α-H and 10β-H compounds (25 and 26a). Deketalization of 25 and 26a with aq. AcOH followed by reduction with NaBH_4 gave (±)-5 and (±)-4,respectively. Esterification of 26a with 2-methylbutyric anhydride-pyridine gave the ester (26b), which was converted to (±)-28a and 28b.
社団法人日本薬学会の論文
1981-12-25