1,3-Dimethyl-2-phenylbenzimidazoline (DMPBI)-Acetic Acid: An Effective Reagent System for Photoinduced Reductive Transformation of α,β-Epoxy Ketones to β-Hydroxy Ketones
作者:Eietsu Hasegawa、Naoki Chiba、Aiko Nakajima、Kumiko Suzuki、Akira Yoneoka、Kazuki Iwaya
DOI:10.1055/s-2001-15055
日期:——
aqueous solvents. When THF solutions containing aryl carbonyl possessing α,β-epoxy ketones and DMPBI and acetic acid were irradiated (λ > 280 nm), β-hydroxy ketones were isolated in good to excellent yields. Photosensitized conditions (λ > 340 nm) were employed for the reactions of alkyl carbonyl possessing α,β-epoxy ketones.
1,3-二甲基-2-苯基苯并咪唑啉 (DMPBI) 和乙酸的组合已用于将 α,β-环氧酮光诱导还原转化为 β-羟基酮。使用几种质子供体进行的光反应研究表明,乙酸优于其他质子供体,例如 HCl、p-TsOH、MeOH 和水。1,3-二甲基-2-苯基苯并咪唑鎓在与乙酸的反应中生成,而 N-苯甲酰基-N,N'-二甲基-邻苯二胺在水性溶剂中生成。当辐照含有具有 α,β-环氧酮和 DMPBI 和乙酸的芳基羰基的 THF 溶液时(λ > 280 nm),β-羟基酮以良好至优异的收率分离。光敏条件(λ > 340 nm)用于具有α,β-环氧酮的烷基羰基的反应。