The macrolide (+)-carbonoiide B, the aglycon of the antibiotic carbomycin B, was synthesized via a convergent sequence. A key step of the approach is the union of aldehyde 6 with stannane 7 in the presence of MgBr2.OEt(2) as Lewis acid to afford the C-1-C-9 fragment 26. This chelation-controlled process uses resident stereochemistry at C-4 to control stereochemistry at C-5 and C-6. Elaboration of this fragment at both ends and incorporation of a C-11-C-15 fragment (hydroxy end 4) via esterification and intramolecular Emmons reaction was used to complete the synthesis.
The stereospecifictotalsynthesis of macrolide antibiotics, carbomycin B and josamycin (leucomycin A3), is described. The key aglycone has been synthesized by coupling two segments of C1–C10 and C11–C16 portions, which are stereospecifically derived from glucose.
描述了大环内酯类抗生素卡波霉素B和交沙霉素(leucomycin A 3)的立体定向全合成。关键的糖苷配基是通过耦合C1–C10和C11–C16部分的两个片段而合成的,这两个片段是立体定向衍生自葡萄糖的。
Total Synthesis of (+)-Carbonolide B
作者:Gary E. Keck、Anandan Palani、Stanton F. McHardy
DOI:10.1021/jo00090a032
日期:1994.6
The macrolide (+)-carbonoiide B, the aglycon of the antibiotic carbomycin B, was synthesized via a convergent sequence. A key step of the approach is the union of aldehyde 6 with stannane 7 in the presence of MgBr2.OEt(2) as Lewis acid to afford the C-1-C-9 fragment 26. This chelation-controlled process uses resident stereochemistry at C-4 to control stereochemistry at C-5 and C-6. Elaboration of this fragment at both ends and incorporation of a C-11-C-15 fragment (hydroxy end 4) via esterification and intramolecular Emmons reaction was used to complete the synthesis.