Studies of diastereoselectivity in Diels-Alder reactions of enantiopure (SS)-2-(p-tolylsulfinyl)-1,4-naphthoquinone and chiral racemic acyclic dienes
Studies of diastereoselectivity in Diels-Alder reactions of enantiopure (SS)-2-(p-tolylsulfinyl)-1,4-naphthoquinone and chiral racemic acyclic dienes
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DOI：
10.1021/jo000210u
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发表时间：
2000-07-14
影响因子：
3.6
通讯作者：
Di Vitta, C
中科院分区：
文献类型：
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作者：
Carreño, MC;García-Cerrada, S;Di Vitta, C
对映体亚磺酸(+)-5通过串联的环加成/热解亚砜消除反应，与具有立体生成烯丙基中心的外消旋开环二烯1a-f反应，得到具有良好的相似/不同选择性(约75：25)和良好的对映体过量(68-82%)的光学富集物8a-f和9a-f。在与双烯1g-I的反应中观察到相反的非对映选择性(8g-I：9g-I，高达5：95)，在C-3上增加了一个甲基，对映体纯度适中(14-25%)。相应方法中的空间效应和扭转相互作用解释了观察到的非对映选择性。
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 diastereoselection (8g-i: 9g-i, up to 5:95) was observed in reactions with dienes 1g-i, having an additional methyl group at C-3, the enantiomeric purities being moderate (14-25%). Steric effects and torsional interactions in the corresponding approaches account for the observed diastereoselectivities.