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Publication 193
- Total synthesis of the macrolide (+)-aspicilin by an asymmetrically catalyzed macrocyclization of an ω-Alkynal ester
Oppolzer, W.; Radinov, R. N.; de Brabander, J.
Tetrahedron Lett. 1995, 36, 2607-2610
ω-Alkynal ester 3, prepared from (S)-propylene oxide 4, yields the macrocyclic (6R)-allylic alcohol 2 (60% yield, 83% d.e.) in one operation via monohydroboration, boron/zinc-transmetalation and (−)-DAIB “catalyzed” intramolecular alkenylzinc/aldehyde addition. Introduction of the C(2)–C(3) double bond by selenoxide elimination (2 → 8), hydroxy-directed epoxidation (8 → 9), acetate assisted α-epoxide opening (10 → 12) and acidic methanolysis provides pure (+)-aspicilin (1) in 22% overall yield from 4.
DOI : 10.1016/0040-4039(95)00351-C
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