Generation of cationic 2-azabutadienes from N,S-acetals and their use for the regio- and diastereoselective synthesis of 1,2,3,4-tetrahydroquinolines by intermolecular [4π++2π] cycloadditions
Generation of cationic 2-azabutadienes from N,S-acetals and their use for the regio- and diastereoselective synthesis of 1,2,3,4-tetrahydroquinolines by intermolecular [4π++2π] cycloadditions
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DOI：
10.3998/ark.5550190.0006.514
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发表时间：
2005-01-01
期刊：
影响因子：
0.9
通讯作者：
Ondrus, V
中科院分区：
文献类型：
--
作者：
Beifuss, U;Ledderhose, S;Ondrus, V
通过阳离子2-氮杂丁二烯和各种亲二烯体的分子间极性[4 π（+）+2 π]环加成反应，高度区域选择性和非对映选择性地形成取代的1，2，3，4-四氢喹啉和相关的N-杂环，产率为57 - 100%。通过刘易斯酸介导的N，S-缩醛的异裂解，可以原位生成阳离子2-氮杂丁二烯。使用由TiCl 4和PPh 3的混合物组成的新的混合刘易斯酸获得了最好的结果。
Substituted 1,2,3,4-tetrahydroquinolines and related N-heterocycles are formed highly regio- and diastereoselectively with yields ranging from 57 to 100% by intermolecular polar [4 pi(+) + 2 pi] cycloadditions of cationic 2-azabutadienes and various dienophiles. The cationic 2-azabutadienes can be generated in situ by Lewis acid mediated heterolytic cleavage of N,S-acetals. Best results have been obtained using a new mixed Lewis acid consisting of a mixture of TiCl4 and PPh3.