1981 年 29 巻 12 号 p. 3474-3485
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 SOCl2-pyridine gave the corresponding 1, 10-dehydro-6, 9-dioxo compounds (11, 20 and 24, respectively). NaBH4 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 H2/Pd gave the 10α-H and 10β-H compounds (25 and 26a). Deketalization of 25 and 26a with aq. AcOH followed by reduction with NaBH4 gave (±)-5 and (±)-4, respectively. Esterification of 26a with 2-methylbutyric anhydride-pyridine gave the ester (26b), which was converted to (±)-28a and 28b.
