Reductive coupling of hydantoins with benzophenones by low-valent titanium: Synthesis of 4-substituted 1H-imidazol-2(3H)-ones and unusual two-to-two coupled products
作者:Naoki Kise、Shuta Goi、Toshihiko Sakurai
DOI:10.1016/j.tet.2018.01.022
日期:2018.3
The reductive coupling of 1,3-dimethyhydantoin with benzophenones by TiCl4-Zn in THF gave 4-diarylmethyl-1H-imidazol-2(3H)-ones as four-electron reduced one-to-one coupled products and their dimers as two-to-two coupled products predominantly by controlling the reaction conditions. The reductive coupling of 5-alkyl-1,3-dimethyhydantoins with benzophenones produced 5-alkyl-4-diarylmethyl-1H-imidazol-2(3H)-ones
TiCl 4 -Zn在THF中将1,3-二甲基乙内酰脲与二苯甲酮还原偶合得到4-二芳基甲基-1 H-咪唑-2(3 H)-ones,为四电子还原的一对一偶合产物及其二聚体主要通过控制反应条件将其作为二对二偶联产物。5-烷基-1,3-二甲基乙内酰脲与二苯甲酮的还原偶联产生5-烷基-4-二芳基甲基-1 H-咪唑-2(3 H)-作为唯一产物,而与反应条件无关。另一方面,1,3-二甲基乙内酰脲与环状二苯甲酮的还原偶联选择性地使4-芳基羟甲基-1 H-咪唑-2(3 H)-酮作为两电子还原一对一的偶合产物,然后进一步还原为4-二芳基甲基-1 H-咪唑-2(3 H)-酮。