Alkylphosphonous acid diesters MeP(OR)23a-b were shown to be highly effctive and mild reducing reagents in the oxalimide cyclization of azetidinone-1-oxalyl-4-di- or tri-thiocarbonates or 4-thioesters1a-t forming penems 2a-t at lower temperature shorter reaction times, and higher yields compared to classical phosphites P(OMe)3 and P(OEt)3.
烷基
亚膦酸二酯MeP(OR)2 3a-b在氮杂
环丁酮-1-草酰-4-二-或
三硫代碳酸酯或4-
硫酯1a-t生成青霉烯2a-t的草
酰亚胺环化反应中显示出高效率和温和的还原剂与传统的
亚磷酸酯P(OMe)3和P(OEt)3相比,在较低的温度下t的反应时间更短,产率更高。