摘要：

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.

展开