STEREOSELECTIVE SYNTHESIS OF DIMETHYLROBUSTADIALS
STEREOSELECTIVE SYNTHESIS OF DIMETHYLROBUSTADIALS
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DOI：
10.1021/jo00101a031
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发表时间：
1994-11-04
影响因子：
3.6
通讯作者：
BANTLE, GW
中科院分区：
文献类型：
--
作者：
MAJEWSKI, M;IRVINE, NM;BANTLE, GW
描述了Robustadiales A和B的甲基醚的立体选择性合成（24）。关键步骤是烯酮8b的胺催化环化，其导致具有高非对映选择性的产物9 b和10 b。胺催化剂的选择对选择性（即对反式和顺式产物的比率9 B：10 B）具有强烈影响;胺必须具有最佳pK（B）值。通过取代苯甲醛（3b）与β-蒎烯（4）的Prins反应，将Robustadials的芳香合成子和萜烯合成子连接起来。该反应强烈依赖于电子效应，并且芳环上取代基的选择是关键的。（1 S）-（-）-β-蒎烯的使用确保了对映体纯化合物的合成。
A stereoselective synthesis of the methyl ethers of robustadials A and B (24) is described. The crucial step is the amine-catalyzed cyclization of the enone 8b which leads to the products 9b and 10b with high diastereoselectivity. The choice of the amine catalyst has a strong influence on the selectivity (i.e. on the ratio of trans and cis products 9b:10b); the amine must have an optimum pK(b) value. The aromatic synthon and the terpene synthon of robustadials are joined via a Prins reaction of a substituted benzaldehyde (3b) with beta-pinene (4). The reaction is strongly dependent on electronic effects, and the choice of substituents on the aromatic ring is critical. The use of (1S)-(-)-beta-pinene ensures the synthesis of enantiomerically pure compounds.