Yakura Takayuki, Fujiwara Tomoya, Yamada Akihiro, Nambu Hisanori
Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Sugitani, Toyama 930-0194, Japan.
Beilstein J Org Chem. 2018 Apr 30;14:971-978. doi: 10.3762/bjoc.14.82. eCollection 2018.
Several -isopropyliodobenzamides were evaluated as catalysts for the oxidation of benzhydrol to benzophenone in the presence of Oxone (2KHSO·KHSO·KSO) as a co-oxidant at room temperature. A study on the substituent effect of the benzene ring of -isopropyl-2-iodobenzamide on the oxidation revealed that its reactivity increased in the following order of substitution: 5-NO < 5-COMe, 3-OMe < 5-OAc < 5-Cl < H, 4-OMe < 5-Me < 5-OMe. The oxidation of various benzylic and aliphatic alcohols using a catalytic amount of the most reactive 5-methoxy derivative successfully resulted in moderate to excellent yields of the corresponding carbonyl compounds. The high reactivity of the 5-methoxy derivative at room temperature is a result of the rapid generation of the pentavalent species from the trivalent species during the reaction. 5-Methoxy-2-iodobenzamide would be an efficient and environmentally benign catalyst for the oxidation of alcohols, especially benzylic alcohols.
在室温下，以过一硫酸氢钾复合盐（2KHSO₅·KHSO₄·K₂SO₄）作为共氧化剂，评估了几种对异丙基碘代苯甲酰胺作为将二苯甲醇氧化为二苯甲酮的催化剂。一项关于对异丙基-2-碘代苯甲酰胺苯环取代基效应的氧化研究表明，其反应活性按以下取代顺序增加：5-NO₂＜5-COMe，3-OMe＜5-OAc＜5-Cl＜H，4-OMe＜5-Me＜5-OMe。使用催化量的反应活性最高的5-甲氧基衍生物对各种苄醇和脂肪醇进行氧化，成功得到了相应羰基化合物的中等至优异产率。5-甲氧基衍生物在室温下的高反应活性是反应过程中三价物种快速生成五价物种的结果。5-甲氧基-2-碘代苯甲酰胺将是一种用于醇类尤其是苄醇氧化的高效且环境友好的催化剂。
