Treatment of 4-acetoxy-2-azetidinone (9) with various sodium alkyl trithiocarbonates gave 4-[(alkylthio) thiocarbonyl] thioazetidinones 10, which were converted into the phosphoranes 8. Intramolecular Wittig reactions of 8 followed by deblocking yielded penem-3-carboxylic acids 5.
用各种烷基
三硫代碳酸钠处理
4-乙酰氧基-2-氮杂环丁酮(9)得到了4-[(烷
硫基)
硫代羰基]
硫代氮杂
环丁酮10,这些化合物被转化为
磷叶立德8。8的分子内Wittig反应随后进行脱保护反应生成了青霉烯-3-
羧酸5。