31 カルボマイシンBおよびジョサマイシン(ロイコマイシンA_3)の全合成

概要

論文の詳細を見る
Medicinally important 16-membered-ring macrolide antibiotics, carbomycin B (1) and josamycin (2, leucomycin A_3), have been stereospecifically synthesized by using D-glucose as a major chiral source. The Michael reaction of the unsaturated ester, which was derived from the furanose 4 by the Wittig reaction, with the lithiated methyl methylthiomethyl sulfoxide gave stereospecifically the adduct 7, which, in turn, was converted into the aldehyde 10. The second Wittig reaction with the ylid 11 followed by reduction afforded a C1-C10 segment. Selective oxidation of the primary alcohol followed by esterification provided the methyl ester 13, which was coupled with an aldehyde segment 15 corresponding to C11-C16 to give the naturally derived unsaturated ketone 16. Alkaline hydrolysis followed by lactonization gave the 16-membered lactone 20, which was converted into the ethylene acetal aglycone 24. Since the key aglycone 24 has already been transformed into carbomycin B (1) and josamycin (2, leucomycin A_3), the total synthesis of 24 constitutes the completion of the task.
天然有機化合物討論会の論文
1980-09-10