An Alternative Role for Acetylenes: Activation of Fluorobenzenes toward Nucleophilic Aromatic Substitution
作者:Nicholas P. Bizier、Jay Wm. Wackerly、Eric D. Braunstein、Mengfei Zhang、Stephen T. Nodder、Stephen M. Carlin、Jeffrey L. Katz
DOI:10.1021/jo400668v
日期:2013.6.21
aspect of arylacetylene reactivity by utilizing alkynes as electron-withdrawing groups (EWG) for promoting nucleophilicaromaticsubstitution (SNAr) reactions. Reaction rates for the substitution of 4-(fluoroethynyl)benzenes by p-cresol were determined by 1H NMR spectroscopy, and these rate data were used to determine substituent (Hammett) constants for terminal and substituted ethynyl groups. The synthetic
A radical cascade reaction of 2-aryloxy phenylacetylenes with phosphineoxides promoted by K2S2O8 was developed, which provided diphosphonyl xanthenes as products. This reaction proceeds under transition metal-free and mild conditions with simple operation and good yields. The mechanistic study indicated that phosphineoxide was induced into a phosphonyl radical, and then the following double radical
开发了由 K 2 S 2 O 8促进的 2-芳氧基苯乙炔与氧化膦的自由基级联反应,得到二膦酰基呫吨产物。该反应在无过渡金属、温和条件下进行,操作简单,收率良好。机理研究表明,氧化膦被诱导为膦酰基自由基,随后与2-芳氧基苯乙炔的双自由基加成/环化生成双膦酰基氧杂蒽。