Xie Sheng, Ramström Olof, Yan Mingdi
Department of Chemistry, KTH - Royal Institute of Technology , Teknikringen 36, Stockholm, Sweden.
Org Lett. 2015 Feb 6;17(3):636-9. doi: 10.1021/ol503655a. Epub 2015 Jan 23.
Urea structures, of which N,N-diethylurea (DEU) proved to be the most efficient, were discovered to catalyze amidation reactions between electron-deficient aryl azides and phenylacetaldehydes. Experimental data support 1,3-dipolar cycloaddition between DEU-activated enols and electrophilic phenyl azides, especially perfluoroaryl azides, followed by rearrangement of the triazoline intermediate. The activation of the aldehyde under near-neutral conditions was of special importance in inhibiting dehydration/aromatization of the triazoline intermediate, thus promoting the rearrangement to form aryl amides.
已发现尿素结构（其中N,N-二乙基脲（DEU）被证明是最有效的）可催化缺电子芳基叠氮化物与苯乙醛之间的酰胺化反应。实验数据支持DEU活化的烯醇与亲电苯基叠氮化物（尤其是全氟芳基叠氮化物）之间的1,3-偶极环加成反应，随后是三唑啉中间体的重排。在接近中性条件下醛的活化对于抑制三唑啉中间体的脱水/芳构化特别重要，从而促进重排以形成芳基酰胺。
