Synthesis of Quillaic Acid through Sustainable C-H Bond Activations
Journal
Journal of Organic Chemistry
Journal Volume
89
Journal Issue
8
Start Page
5491
End Page
5497
ISSN
1520-6904
Date Issued
2024-04-19
Author(s)
Abstract
To meet the demand for quillaic acid, a multigram synthesis of quillaic acid was accomplished in 14 steps, starting from oleanolic acid, leading to an overall yield of 3.4%. Key features include C-H activation at C-16 and C-23. Through Pd-catalyzed C-H acetoxylation, the oxidation at C-23 was observed as the major product, as opposed to at C-24. A copper-mediated C-H hydroxylation using O successfully afforded the single isomer, 16β-ol triterpenoid, followed by configuration inversion to the desired 16α-ol compound. In summary, with steps optimized and conducted on a multigram scale, quillaic acid could be feasibly acquired through C-H activation with inexpensive copper catalysts, promoting a more sustainable approach.
Type
journal article