Stereoselective Synthesis of Medium-sized Carbocyclic Compounds by Tandem Reactions of Cyclic Sulfur Ylides

五元氧代锍叶立德与Baylis-Hillman加成物的乙酸酯反应，通过串联的Michael -分子内Corey-Chaykovsky反应，以19- 74%的产率高立体选择性地得到环庚烯氧化物衍生物.所得化合物的立体化学通过X射线分析阐明。从立体化学的结果，分子内Corey反应是通过一个刚性的双环中间体含有椅子形硫杂环己烷环进行。此外，还研究了相应的六元硫叶立德的相同反应。因此，以7- 46%的产率获得与硫原子构型相关的非对映异构体的4：1混合物形式的环辛烯氧化物衍生物。此外，为了评价环硫叶立德的反应活性，尝试了环硫叶立德与醛和烯酮的反应。所有反应都以优异的产率提供了Corey反应产物（环丙烷或环氧乙烷衍生物）。另一方面，六元氧代锍叶立德与4-己烯-2-酮在两种等摩尔碱存在下反应，得到了一种新型的八元碳环化合物（叶立德与烯酮的1：2加合物），具有很高的立体选择性。

The reaction of a five-membered oxosulfonium ylide with acetates of Baylis - Hillman adducts afforded cycloheptene oxide derivatives with high stereoselectivity in 19-74 % yields via tandem Michael - intramolecular Corey -Chaykovsky reactions. The stereochemistry of resulting compounds was elucidated by an X-ray analysis. From the results of the stereochemistry, an intramolecular Corey reaction was implied to proceed via a rigid bicyclic intermediate containing a chair-form thiacyclohexane ring. In addition, the same reaction of the corresponding sixmembered sulfur ylide was investigated. Consequently, cyclooctene oxide derivatives were obtained in 7-46 % yields as a 4 : 1 mixture of diastereomers relevant to the configuration of sulfur atom. Moreover, the reactions of the cyclic sulfur ylides with aldehydes and enones were attempted in order to evaluate the reactivity of cyclic sulfur ylides. All of the reactions provided the Corey reaction products ( cyclopropane or oxirane derivatives ) in excellent yields. On the other hand, the reaction of the six-membered oxosulfonium ylide with 4-hexen-2-one in the presence of two equimolar amount of base gave a novel eight-membered carbocyclic compound ( 1 : 2 adduct of ylide and enone ) with high stereoselectivity.