Methylenomycin B (1) was prepared from diethyl 2-oxopropanephosphonate (5) in four steps in 26% yield. The key steps in this synthesis include the Wittig-Horner reaction of 5 with methylthioethanal (7) followed by the 1,4-addition of a propionyl anion equivalent to the α-enone 4 formed affording 4-(methylthiomethyl)-hepta-2,5-dione (3) which is an acyclic precursor of the title antibiotic.
美克
酮霉素B (1) 通过四个步骤从
二乙基2-氧基
丙烷磷酸酯 (5) 制备而成,产率为26%。该合成的关键步骤包括5与甲基
硫醇
乙醛 (7) 的威提希-霍尔纳反应,随后是丙酰阴离子当量对形成的α-烯酮4的1,4-加成,得到4-(甲基
硫甲基)-庚-2,5-二酮 (3),该化合物是该抗生素的无环前体。