β-Amido sulfoxides (1) reacted with O-silylated ketene acetal (16) in dry acetonitrile in the presence of a catalytic amount of zinc iodide to give the 4-phenylthioazetidin-2-ones (17). Oxidation of 17 with m-chloroperbenzoic acid gave the corresponding sulfoxides (18), which were treated with 16 to give the azetidin-2-one esters (20), known precursors of PS-5-type carbapenem antibiotics.
在干燥的
乙腈中,在一定量的
碘化锌催化下,β-酰胺基
硫醚(1)与 O-
硅烷化酮
缩醛(16)发生反应,得到 4-苯
硫基氮杂
环丁烷-2-酮(17)。用间
氯过
苯甲酸氧化 17 得到相应的
硫氧化物 (18),再用 16 处理得到氮杂
环丁烷-2-
酮酯 (20),这是已知的 PS-5 型碳青霉烯类抗生素的前体。