Catalytic enantioselective Friedel-Crafts/Michael addition reactions of indoles to ethenetricarboxylates.
Catalytic enantioselective Friedel-Crafts/Michael addition reactions of indoles to ethenetricarboxylates.
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DOI：
10.1021/jo052041p
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发表时间：
2006-01
期刊：
影响因子：
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通讯作者：
S. Yamazaki;Y. Iwata
中科院分区：
文献类型：
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作者：
S. Yamazaki;Y. Iwata
[反应：见正文] Friedel-Crafts反应是形成新的C-C键的重要反应。最近，亚烷基丙二酸酯的催化不对称Friedel-Crafts反应被报道。然而，亚烷基丙二酸酯中的取代基是有限的。为了探索新的取代基，如羧基和羰基，催化反应性乙烯三羧酸酯和酰基取代的亚甲基丙二酸酯1的不对称选择性的Friedel-Crafts反应进行了研究。1与吲哚在催化量的手性双恶唑啉铜（II）络合物（10%）存在下在THF中于室温下反应得到烷基化产物，产率高达95%ee。对映选择性可以通过吲哚接近1-Cu（II）-配体络合物的较少受阻侧的次级轨道相互作用来解释。
[reaction: see text] The Friedel-Crafts reaction is an important reaction for the formation of new C-C bonds. Recently, catalytic enantioselective Friedel-Crafts reaction of alkylidene malonates has been reported. However, the substituents in alkylidene malonates are limited. To explore new substituents such as carboxyl and carbonyl groups, catalytic enantioselective Friedel-Crafts reactions of reactive ethenetricarboxylates and acyl-substituted methylenemalonates 1 were investigated. The reaction of 1 with indoles in the presence of catalytic amounts of chiral bisoxazoline copper(II) complex (10%) in THF at room temperature gave alkylated products in high yields and up to 95% ee. The enantioselectivity can be explained by the secondary orbital interaction on approach of indole to the less hindered side of the 1-Cu(II)-ligand complex.