Diastereoselective Ritter-like Reaction on Cyclic Trifluoromethylated N,O-Acetals Derived from L-Tartaric Acid
Diastereoselective Ritter-like Reaction on Cyclic Trifluoromethylated N,O-Acetals Derived from L-Tartaric Acid
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DOI：
10.1021/acs.joc.7b01814
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发表时间：
2017-10-06
影响因子：
3.6
通讯作者：
Grellepois, Fabienne
中科院分区：
文献类型：
--
作者：
Ben Jamaa, Abdelkhalek;Grellepois, Fabienne
尽管存在高度吸电子的氟化取代基，但从氟化O-乙酰基-N，O-缩醛（L）-酒石酸衍生物成功地生成了环状α-三氟甲基化N-酰基咪唑离子。腈在这些中间体上的加成以高至优异的顺式非对映选择性发生，并且在大多数情况下导致恶唑啉和酰胺作为单一非对映异构体。加成的非对映选择性和反应产物的性质取决于酒石酸骨架的羟基上的取代基。该方法获得了对映体纯的高度官能化的5-（三氟甲基）吡咯烷-2-酮衍生物，其在四取代碳上具有氟化取代基。
Despite the presence of the highly electron-withdrawing fluorinated substituent, cyclic alpha-trifluoromethylated N-acyliminium ions were successfully generated from fluorinated O-acetyl-N,O-acetal (L)-tartaric acid derivatives. The addition of nitriles on these intermediates occurred with high to excellent syn diastereoselectivity and led, in most cases, to oxazolines and amides as single diastereomers. The diastereoselectivity of the addition and the nature of the reaction product depend on the substituents on the hydroxyl groups of the tartaric acid scaffold. This methodology gave access to enantiopure, highly functionalized 5-(trifluoromethyl)pyrrolidin-2-one derivatives, bearing the fluorinated substituent on a tetrasubstituted carbon.