Intramolecular Michael-aldol condensation approach to the construction of advanced intermediates in the synthesis of forskolin
Intramolecular Michael-aldol condensation approach to the construction of advanced intermediates in the synthesis of forskolin
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DOI：
10.1021/jo00268a013
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发表时间：
1989-03
影响因子：
3.6
通讯作者：
C. Somoza;J. Darias;E. Rúveda
中科院分区：
文献类型：
--
作者：
C. Somoza;J. Darias;E. Rúveda
通过使用分子内迈克尔加成（7 c- 10）和分子内羟醛缩合（10-*· 6），从β-酮酸酯7 c制备三环β-不饱和酮6。从6开始，制备烯丙醇17 a和17 b。17 a和17 b的立体化学特征通过分析它们的NMR谱来确定，并通过17 b转化为已知的甲基醚17 c来进一步证实。通过一个简单的合成程序，17 b依次转化为已知的丙酮化合物19 c。化合物17 b和19 c是合成forskolin（1）的重要中间体。
The tricyclic, ß-unsaturated ketone 6 has been elaborated from the ß-keto ester 7c by using an intramolecular Michael addition (7c— 10), in tandem with an intramolecular aldol condensation (10-*· 6). Starting from 6, the allylic alcohols 17a and 17b were prepared. The stereochemical features of 17a and 17b were determined by analysis of their NMR spectra and further confirmedby transformation of 17b into the known methyl ether 17c. Through a simple synthetic sequence, 17b was, in turn, converted to the known acetonide 19c. Compounds 17b and 19c are significant intermediates for thesynthesis of forskolin (1).