Cu-catalyzed convenient synthesis of 2-trifluoromethyl benzimidazoles <i>via</i> cyclization of <i>o</i>-phenylenediamines with hexafluoroacetylacetone
作者:Xia Chen、Xiao-Yu Zhou、Hai-Long Liu、Sheng Zhang、Ming Bao
DOI:10.1039/d3ob01702h
日期:——
with hexafluoroacetylacetone proceeded smoothly in the presence of Cu2O as the catalyst to produce 2-trifluoromethyl benzimidazoles in satisfactory to excellent yields (up to >99% yield). The CF3 source, hexafluoroacetylacetone, acted not only as cyclization partner, but also acted as a ligand for the Cu catalyst. Various synthetically useful functional groups, such as halogen atoms, cyano, and methoxycarbonyl
本文描述了一种高效、便捷的2-三氟甲基苯并咪唑的合成方法。在 Cu 2 O 催化剂存在下,各种邻苯二胺与六氟乙酰丙酮的环化反应顺利进行,生成 2-三氟甲基苯并咪唑,收率令人满意(高达 >99%)。 CF 3源六氟乙酰丙酮不仅充当环化配偶体,而且充当Cu催化剂的配体。各种合成上有用的官能团,例如卤素原子、氰基和甲氧基羰基,在环化反应过程中保持完整。对该反应机理进行了彻底的研究,确定涉及七元环状二亚胺中间体。
An efficient method to access 2-fluoroalkylbenzimidazoles by PIDA oxidation of amidines
A mild and practical strategy for the synthesis of 2-bromodifluoromethyl (or trifluoromethyl)-1H-benzimidazoles via PIDA-mediated oxidative intramolecular cyclization of the fluorinated amidines is described. The approach has the advantages of superior yields, excellent functional groups tolerance and mild reaction conditions. (C) 2011 Elsevier B.V. All rights reserved.
Belcher et al., Journal of the Chemical Society, 1954, p. 4159