Cycloadditions in syntheses. XXXVII. Syntheses of 6-trifluoromethyl-1,2,4-triazines and -1,2,4-triazin-5-ones and their pericyclic reactions with olefins.
作者:NOBUYA KATAGIRI、HIROSHI WATANABE、CHIKARA KANEKO
DOI:10.1248/cpb.36.3354
日期:——
6-Trifluoromethyl-1, 2, 4-triazines and -1, 2, 4-triazin-5-ones were synthesized to investigate the role of the trifluoromethyl group in their thermal as well as photochemical cycloaddition reactions with olefins. In photochemical 2+2 cycloaddition using the triazin-5-ones and -3, 5-diones, the activation of the imine function by the trifluoromethyl group is demonstrated and a new route to azetidine derivatives having a trifluoromethyl group is disclosed. In thermal 4+2 cycloaddition using the corresponding triazines, acceleration of the so-called inverse electron demand Diels-Alder reaction is demonstrated. Clarification of the mechanisms of these reactions and their use in the synthesis of azetidin-2-ones and pyridines having a trifluoromethyl group are also described.
6-三氟甲基-1,2,4-三嗪和-1,2,4-三嗪-5-酮被合成,以研究三氟甲基在其与烯烃的热和光化学环加成反应中的作用。在光化学2+2环加成反应中使用三嗪-5-酮和-3,5-二酮时,通过三氟甲基对亚胺功能的活化得以展现,并揭示了一条通向含有三氟甲基的氮杂环丁烷衍生物的新途径。在热4+2环加成反应中使用相应三嗪时,证明了所谓的逆电子需求狄尔斯-阿尔德反应的加速。这些反应的机制澄清及其在合成含有三氟甲基的氮杂环丁烷-2-酮和吡啶中的应用也被描述。