The Biomimetic Synthesis of (-)-Kaur-16-en-19-oic Acid

通过阳离子烯烃聚环反应，尝试对映选择性地合成(-)-kaur-16-en-19酸。手性将通过Sharpless不对称环氧化反应形成对映选择性环氧化物。关键反应将在一个协调的反应步骤中同时产生3个碳环和5个连续的立体中心，并有望在产物分子中产生高的对映选择性。目标是一种天然产物，其生物活性类似于赤霉素一种植物生长激素。它通常与赤霉素一起从各种植物中分离出来，可能是赤霉素生物合成的中间体。提出的合成改进了已发表的立体选择合成策略，将支持目标化合物的成功合成。预计该提案的成功完成将允许开发一种通用的获取方法，该方法可用于与(-)-kaur-16-en-19-oic酸相关的具有更重要（即抗微生物、杀锥虫和抗艾滋病毒）生物活性的其他二萜类天然产物靶标。

The biomimetic total synthesis of (-)-kaur-16-en-19 oic acid will be attempted enantioselectively via a cation olefin polyannulation reaction. Chirality will be introduced by enantioselective epoxide formation via Sharpless asymmetric epoxidation. The key reaction will create three carbocycles and five contiguous stereocenters simultaneously in a single concerted reaction step and is expected to produce high enantioselectivities in the product molecule. The target is a natural product that has biological activity similar to gibberelines a plant growth hormone. It is often isolated from various plant species along with gibberellines, and may be an intermediate in gibberellin biosynthesis. The proposed synthesis improves upon published synthesis by Stereoselective strategies that will support a successful synthesis of the target compound. It is anticipated that a successful completion of the proposal will allow for the development of a general method of access that is modifiable for other diterpenoid natural product targets related to (-)-kaur-16-en-19-oic acid that possess more significant (i.e. anti- microbial, trypansomicidal and anti-HIV) biological activity.