Studies toward the total synthesis of 1-oxacephalosporins 2: synthesis and reactions of oxazolinoazetidinones bearing a γ,γ'-bis-oxygen-functionalized β-methylbutenoate side chain
作者:Dieter Hoppe、Hans Schmincke、Heinz-Werner Kleemann
DOI:10.1016/0040-4020(89)80099-7
日期:1989.1
The racemic title compounds 3 were prepared by chlorolysis of the appropriate 3-acylamino-4-methylthio-2-azetiainones 1. The cleavage of the 1,3-dioxane ring was accomplished by proton and Lewis acids to form the intermediate diols 8, which rapidly undergo lactonization with formation of hydroxymethyl substituted butenolides 10. Neither 8 nor 10 cyclizes to give the 1-oxacephems 9 or 12. A convenient
外消旋的标题化合物3是通过适当的3-酰基氨基-4-甲硫基-2-氮杂环丁烷酮1的氯解反应制备的。1,3-二恶烷环的裂解是通过质子和路易斯酸形成的中间体二醇8进行的,该中间体迅速发生内酯化反应,形成羟甲基取代的丁烯内酯10。8和10都不环化生成1-氧杂苯醚9或12。给出了一种方便的一锅法,用于从1b合成恶唑啉基-氮杂环丁酮羟甲基丁烯内酯10b。