IMPROVED SYNTHESIS OF BRASSINOLIDE

Authors
MCMORRIS TC CHAVEZ RG PATIL PA
Citation
Tc. Mcmorris et al., IMPROVED SYNTHESIS OF BRASSINOLIDE, Journal of the Chemical Society. Perkin transactions. I, (3), 1996, pp. 295-302
Citations number
32
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Journal of the Chemical Society. Perkin transactions. I → ACNP
ISSN journal
0300922X
Issue
3
Year of publication
1996
Pages
295 - 302
Database
ISI
SICI code
0300-922X(1996):3<295:ISOB>2.0.ZU;2-X
Abstract
Brassinolide has been synthesized from stigmasterol in an overall yiel d of 7%. The key step in the synthesis is aldol condensation of 2 alph a, 3 alpha-isopropylidenedioxy-6-oxo-23,24-dinor-5 alpha-cholan-22-al with 3-isopropylbut-2-enolide carried out at -78 degrees C, which give s a product with 22R,23R stereochemistry in high yield, Catalytic hydr ogenation of this product is highly stereoselective leading to the des ired 24S stereochemistry in an intermediate which is readily transform ed into brassinolide.