Reaction of triflyl-imidazole with aldoximes: facile synthesis of nitriles and formation of novel aldoxime-bis(N-triflyl)-imidazole adducts
作者:Rajesh G. Kalkhambkar、Scott D. Bunge、Kenneth K. Laali
DOI:10.1016/j.tetlet.2011.07.135
日期:2011.10
and heteroaromatic nitriles from the corresponding aldoximes has been demonstrated. With benzaldoximes, in the presence of certain substitutents (2-F; 2-OMe; 3-CF3; 2-Me-5-F) a different course of reaction was observed, leading instead to novel 1:1 aldoxime-bis(N-triflyl)imidazole covalent adducts, in which the aldoxime oxygen atom is bonded to the imidazole C-2 ring carbon. For these aldoximes, conversion
已经证明了N-三氟代咪唑作为原位试剂的合成效用,用于从相应的醛肟方便,高产地合成各种脂族,芳族和杂芳族腈。对于苯甲醛肟,在某些取代基(2-F; 2-OMe; 3-CF 3; 2-Me-5-F)存在下,观察到不同的反应过程,从而导致出现新型的1:1醛肟-bis(N-三氟甲基)咪唑共价加合物,其中醛肟氧原子与咪唑C-2环碳键合。对于这些醛肟,可以通过与Tf 2反应来转化为腈O在不存在咪唑的情况下。通过X射线分析确认了由2-甲基-5-氟-苯甲酰肟形成的加合物的分子结构。已经考虑了形成1:1共价加合物的合理机制。通过双(N-三氟乙)咪唑鎓三氟甲磺酸的真实样品与醛肟的反应分离这种加合物的各种尝试均未成功。值得注意的是,尽管分离的苯并肟肟加合物用NaH / MeI进行了去质子化/甲基化,但在这些条件下,真实的三氟甲磺酸双(N- triflyl)咪唑鎓样品未进行H / Me交换。讨论了这些转换。