[Development of boomerang-type intramolecular cascade reactions and application to natural product synthesis].
[Development of boomerang-type intramolecular cascade reactions and application to natural product synthesis].
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回旋镖型分子内级联反应的进展及其在天然产物合成中的应用
DOI：
10.1248/yakushi.121.887
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
K. Takasu
中科院分区：
文献类型：
--
作者：
K. Takasu
分子内级联反应作为一种构建有机合成中多环骨架的有效方法，受到了人们的广泛关注。我们一直在开发“回旋杆式级联反应”，以高效地构建各种多环骨架。在上述反应中，底物的亲核功能在第一反应后将性质改变为亲水性，而亲电基团在第二反应中起到亲核剂的作用。也就是说，反应中心通过其他官能团从一个官能团逐步移回相同的官能团。与级联反应有关的电子流就像一个回旋镖的轨迹。我们在这里展示了三种不同的回旋镖类型的反应，通过离子物种或自由基。1)基于手性辅助方法的非对映选择性Michael-Aldol反应和利用外部手性源的不对映选择性Michael-Aldol反应。2)以分子内双Michael加成为关键步骤，短而高效地全合成长叶烷倍半萜。3)卤代多烯构筑萜类骨架的回旋棒型自由基级联反应的发展及其区域选择性。
Intramolecular cascade reaction has received much attention as a powerful methodology to construct a polycyclic framework in organic synthesis. We have been developing "boomerang-type cascade reaction" to construct a variety of polycyclic skeletons efficiently. In the above reactions, a nucleophilic function of substrates changes the character into an electrophile after the initial reaction, and the electrophilic group acts as a nucleophile in the second reaction. That is, the reaction center stepwise moves from one functional group back to the same one via other functional groups. The stream of the electron concerning the cascade reaction is like a locus of boomerang. We show here three different boomerang-type reactions via ionic species or free radicals. 1) Diastereoselective Michael-aldol reaction based on the chiral auxiliary method and enantioselective Michael-aldol reaction by the use of external chiral sources. 2) Short and efficient total syntheses of longifolane sesquiterpenes utilizing intramolecular double Michael addition as a key step. 3) Development of boomerang-type radical cascade reaction of halopolyenes to construct terpenoid skeletons and its regioselectivity.