reduction of dioxygen by Hantzsch ester under mild conditions to allow the aerobic metal-free epoxidation of electron-rich alkenes. Mechanistic crossovers are underlined, explaining the dual role of Hantzsch ester as a reductant/promoter of the DKP catalyst and a simultaneous competitor for the epoxidation of alkenes when HFIP is used as a solvent. Expansion of this protocol to the synthesis of allylic alcohols
吡咯-脯
氨酸二酮
哌嗪 (DKP) 在温和条件下作为 Hantzsch 酯还原分子氧的有效介质,允许富电子烯烃的有氧无
金属环氧化。机械交叉被加下划线,解释了 Hantzsch 酯作为 DKP 催化剂的还原剂/
促进剂的双重作用,以及当 HFIP 用作溶剂时烯烃环氧化的同时竞争者。通过添加催化量的
二氧化硒作为添加剂,将该协议扩展到
烯丙醇的合成,揭示了t- BuOOH 作为
二氧化硒氧化剂的经典应用的优越方法。