25 ツヨプセンの転位反応

概要

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Reaction of tricyclic sesquiterpene hydrocarbon, thujopsene, with proton acids, silica gel and palladium charcoal was investigated in order to see the behavior of cyclopropyl-carbinyl cation formed. Many new products having extensively rearranged structures were isolated and their structures determined by physical and chemical methods. Considering the structure of reaction products, the course of rearrangements in these reactions was illustrated. The reaction of (1) with silica gel is more vigorous compared with the homogeneous acid catalyzed reaction, giving more terminal therefore stable products. The difference of the stereoselectivity between homogeneous (acid-catalyzed reaction) and heterogeneous reaction (reaction with silica gel) was also described. The dehydrogenation of (1) gave daucalene (30) and 4 new compounds, (31), (27), (29) and (28) in addition to (2), (3), (4) and (6). The compounds, (31), (27), (29) and (28) were further dehydrogenated. The existence of two reaction paths was disclosed between (19) and (30). The essential difference of reaction path between general acid and palladium-charcoal was discussed.
天然有機化合物討論会の論文
1970-10-01