Asymmetric 1,3-dipolar cycloaddition of chiral sulphinylethenes with 1-methyl-3-oxido-pyridinium and some nitrones
作者:Tamiko Takahashi、Akihito Fujii、Jun Sugita、Toru Hagi、Kazuyoshi Kitano、Yoshitsugu Arai、Toru Koizumi、Motoo Shiro
DOI:10.1016/s0957-4166(00)80034-8
日期:1991.1
1,3-Dipolar cycloaddition of (R)-(+)-p-tolyl vinyl sulphoxide 1 with 1-methyl-3-oxidopyridinium 6 proceeded in a diastereoselective manner to afford the exo and endo cycloadducts 11a,b and 12a in 36%, 7% and 29% yield, respectively. The absolute configuration of 11a was determined by its transformation to (1S)-(−)-2α-tropanol (−)-15. Attempts to the cycloaddition of the sulphinylethenes 17–19 with
(的1,3-偶极环加成- [R(+) - - )对甲苯基乙烯基砜1与1-甲基-3- oxidopyridinium 6以非对映选择性方式进行,得到外切和内切cycloadducts 11A,B和12A在36% ,分别为7%和29%的收率。11a的绝对构型是通过将其转变为(1 S)-(-)-2α-异丙醇(-)- 15来确定的。在几种条件下,未成功地将亚吡啶基17-19与吡啶鎓6环加成。亚砜20的反应用1-氧化吡咯啉与21分离得到产物的不可分离的混合物。用3,4,5,6-四氢吡啶1-氧化物22对20进行环加成,得到大约4个加合物的混合物。90%的产率。对于内环加成,实现了高水平的非对映选择性,从而以33%的分离产率提供了加合物23。通过单晶X射线衍射研究确认了23的绝对构型。基于产物的绝对构型,讨论了反应的立体化学过程。