Studies of Diastereoselectivity in Diels−Alder Reactions of Enantiopure (S<i>S</i>)-2-(<i>p</i>-Tolylsulfinyl)-1,4-naphthoquinone and Chiral Racemic Acyclic Dienes
作者:M. Carmen Carreño、Susana García-Cerrada、Antonio Urbano、Claudio Di Vitta
DOI:10.1021/jo000210u
日期:2000.7.1
Enantiopure sulfinylnaphthoquinone (+)-5 reacted with racemic acyclic dienes 1a-f bearing a stereogenic allylic center, through a tandem cycloaddition/pyrolytic sulfoxide elimination, to afford optically enriched compounds 8a-f and 9a-f with good like/unlike selectivities (ca. 75:25) and good enantiomeric excesses (68-82%), arising from the partial kinetic resolution of the racemic dienes. The opposite
对映纯亚磺酰基萘醌(+)-5通过串联环加成/热解亚砜与带有立体异构烯丙基中心的消旋无环二烯1a-f反应,得到光学富集的化合物8a-f和9a-f,具有良好的相似/不相似的选择性(ca 75:25)和良好的对映体过量(68-82%),这是由外消旋二烯的部分动力学拆分引起的。在与二烯1g-i的反应中观察到相反的非对映异构(8g-i:9g-i,至5:95),二烯在C-3处具有额外的甲基,对映体纯度为中等(14-25%)。相应方法中的立体效应和扭转相互作用说明了观察到的非对映选择性。