无过渡金属催化苄位碳-氢键直接酯化的交叉脱氢偶联反应研究

A Metal-Free Catalyst Used in Direct Esterification of Benzyl C-H Bond by Cross-Dehydrogenative Coupling

四丁基碘化铵可作为一种绿色、高效的催化剂应用于苄位碳-氢键的交叉脱氢偶联反应。实验表明,含有苄位碳-氢键的化合物和大多数羧酸,都能在此催化体系下直接酯化,以中等至优异的产率获得相应的偶联产物。该方法可作为多种氨基酸衍生物和酮洛芬等生物活性分子的羧基保护反应。通过机理验证实验表明,该反应经历了苄基自由基过渡态的反应历程。

An efficient metal-free oxidative esterification of benzyl C-H bonds was developed.Using Bu4 NI as catalyst,benzyl substrates could react smoothly with various carboxylic acids to give the esters with good to excellent yields.The method was also suitable for the O-protection of N-Boc amino acids.The reaction mechanism was primarily investigated and a radical process was supposed.