Development of Organoiron Methodology for Preparation of the Polyene Natural Product Macrolactin A

• Published in: Tetrahedron Vol. 56; no. 15; pp. 2283 - 2295
• Main Authors: Bärmann, Heiko, Prahlad, Vadapalli, Tao, Chunlin, Yun, Young K, Wang, Zhi, Donaldson, William A
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 07-04-2000
• Subjects: cyclocondensation; macrolactin A; organoiron; macrolactin A; organoiron; cyclocondensation
• ISSN: 0040-4020; 1464-5416
• DOI: 10.1016/S0040-4020(99)01111-4

Methodology for the synthesis of the C7–C13 segment (
19) and C14–C24 segment (
41) of macrolactin A have been developed. Dicarbonyl(methyl 7-nitro-2
E,4
Z-heptadienoate)triphenylphosphineiron (
19) is prepared by nucleophilic addition to a (1-methoxycarbonylpentadienyl)iron cation. The C23 stereocenter of
41 is established by introduction of a C20 stereocenter, chirality transfer from C20 to C23 followed by (diene)iron mediated selective ionic reduction of the C20 hydroxyl. The C15 stereocenter may be established by nitrile oxide–olefin cyclocondensation.