An improved method for the synthesis of γ-lactones using sodium bromate and sodium hydrogen sulfite
作者:Safdar Hayat、Atta-ur-Rahman、M.Iqbal Choudhary、Khalid Mohammed Khan、Ernst Bayer
DOI:10.1016/s0040-4039(00)02341-8
日期:2001.2
two-phase system using ethyl acetate as solvent, under mild conditions to give the corresponding cyclized phthalides in moderate to satisfactory yield. Intermediately the α-brominated alkylbenzenecarboxylic acids are formed by the in situ generated hypobromous acid. These α-brominated acids undergo an intramolecular nucleophilic substitution reaction to afford the corresponding γ-lactones.
在两相系统中,使用乙酸乙酯作为溶剂,在温和的条件下,用溴酸钠和亚硫酸氢钠试剂处理邻烷基苯甲酸,以中等至令人满意的产率得到相应的环化邻苯二甲酸酯。由原位产生的次溴酸中间形成α-溴代烷基苯羧酸。这些α-溴酸经历分子内亲核取代反应,得到相应的γ-内酯。