A stereoselective synthesis of the C(3)-C(13) and C(14)-C(24) fragments ofmacrolactin A

Synthetic studies towards the C(3)-C(13) and C(14)-C(24) segments(3,4) of t he potent antiviral and antitumor compound macrolactin A (1) are presented. Compound 3 Has constructed via a convergent and facile approach, exploitin g Wittig olefination to generate the sensitive E,Z-diene moiety. Compound 4 was synthesized from the chiral-pool derived sulfone 39a ria an alpha -alk ylation-desulfonation reaction sequence. Cu(II)-catalyzed coupling of a Gri gnard reagent with an allylic bromide and Julia olefination were also inves tigated for the preparation of compound 4.