摘要
吲哚膦酸酯是一类重要的化合物,具有潜在的生理活性;此外,从它出发可以衍生出其他多种物质.利用醋酸锰引发二烷基亚膦酸酯产生膦酸酯基自由基与吲哚发生选择性的反应,成功合成了一系列吲哚膦酸酯衍生物,该方法也适用于二苯氧膦.该反应条件较温和、操作简单,为2-和3-膦酰化吲哚的合成提供了一种有效的方法.
Mn（OAc）3-mediated selective radical phosphorylation of indoles with dialkylphosphites or diphenylphosphine oxide in moderate to good yields is described. The reaction proceeds under mild conditions in air, no need to add extra additives, through a radical process involving phosphorus-centered radical generated from dialkylphosphites or diphenylphosphine oxide mediated by Mn（OAc）3, selectively added to 3-position of 2-substituted indoles or 2-position of 3-substituted indoles to form carbon radical intermediate, followed by oxidation with Mn（OAc）3 and deprotonation to afford products 2- or 3-phosphonyl indoles. This protocol provides an efficient and general method for the preparation of 2- and 3-phosphoryl indoles. The detailed investigation revealed that 1） the yields of N-methyl indoles were higher than NH unprotected analogues; 2） 2-Phenyl or 2-methyl indoles were unsuitable for the reaction with dialkylphosphites, but were suitable for the reaction with diphenyl phosphine oxide; 3） Indoles bearing electron-withdrawing groups such as F, Cl, Br on the phenyl ring were favored to the reaction. A representative procedure for this reaction is as follows： To a solution of substituted indoles 1 or 4 （1 retool） and dialkylphosphites 2 （2 mmol） in HOAc （3 mE） heated with oil bath （50℃）, Mn（OAc）3 （3 mmol） was added in portions within 0.5 h, then, the mixture was allowed to stir further for 0.5 h. After removal of the most solvent under reduced pressure, 50 mL water was added to the residue and the mixture was extracted with EtOAc （20 mL × 3）. The combined organic layers were dried over anhydrous Na2SO4, filtered, concentrated under reduced pressure, and the residue was purified by flash silica-gel column chromatography （using mixture of petroleum ether/ethyl acetate as eluent from ratio of 20/1 to 1/2） to afford the desired 2- or 3-phosphonyl indoles 3 or 5.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2016年第10期811-818,共8页
Acta Chimica Sinica
基金
国家自然科学基金(No.21472133)
江苏高校优势学科建设工程资助项目基金
新型功能高分子材料国家地方联合工程实验室项目基金的资助~~
关键词
醋酸锰
自由基反应
吲哚
膦酰化
Mn（OAc）3
radical reaction
indole
phosphorylation
