Concise Synthesis of (−)-GA18 Methyl Ester

Gibberellins (GAs) are important plant hormones, but some of their family members are in extremely limited natural supply including GA18. Herein, we report a concise synthesis of (−)-GA18 methyl ester, a member of the C20 gibberellins, from commercially available and cheap andrographolide. Our synth...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2023-01, Vol.145 (1), p.53-57
Main Authors: Li, Lei, Liang, Weida, Rivera, Mario E., Wang, Ye-Cheng, Dai, Mingji
Format: Article
Language:English
Online Access:Get full text
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Summary:Gibberellins (GAs) are important plant hormones, but some of their family members are in extremely limited natural supply including GA18. Herein, we report a concise synthesis of (−)-GA18 methyl ester, a member of the C20 gibberellins, from commercially available and cheap andrographolide. Our synthesis features an intramolecular ene reaction to form the C ring, an oxidative cleavage followed by aldol condensation to realize a ring contraction and form the challenging trans-hydrindane (AB ring), and a photochemical [2+2] cycloaddition accompanied by a subsequent SmI2-mediated skeletal rearrangement to construct the methylenebicyclo[3.2.1]­octanol moiety (CD ring).
ISSN:0002-7863
1520-5126
1520-5126
DOI:10.1021/jacs.2c12470