71 Clerodane型ジテルペンの合成研究

概要

論文の詳細を見る
This paper deals with two approaches toward the total syntheses of clerodane diterpenes. Cascarillone 34 has been elaborated by our second approach, which represents the first total synthesis of cis-clerodane diterpene. The first approach starts from the intermediate 4, in which the stereochemistry at C-8, C-9 and C-10 has been secured by Diels-Alder reaction. 4 is converted to the keto-lactone 9, of which methylation after blocking of C-3 methylene group affords cis-decalin derivative 11. The transformation of 11 to 15, a critical intermediate for the synthesis of cis-clerodane diterpene 16 has been accomplished. The second approach takes advantage of the reported stereospecific formation of 30 by conjugate addition. The kinetically formed enolate in the reaction is trapped by formaldehyde and the further annelation procedures give a key intermediate 33. The application of conjugate addition-alkylation method to 33 yields a mixture of dimethylated products 36. The side chain construction on 36 by established procedures produces cascarillone 34.
天然有機化合物討論会の論文
1978-08-22