Yoshida S * et al. Astellas Pharma Inc., Ibaraki and Tokyo, Japan
A Challenging Synthesis of the Highly Functionalized Echinocandin ASP9726: A Successor
of Micafungin.
Org. Process Res. Dev. 2014;
18: 725-738
Key words
ASP9726 - reductive amination - amide dehydration - enzymatic hydrolysis of amides
Significance
An 11-step synthesis of the antifungal agent ASP9726 (13.8% overall) from the fermentation
product FR901379 is described that is remarkable for the highly chemoselective transformations
on functionally dense substrates.
Comment
The closing stages of the synthesis feature the reductive amination of primary amine
C with dihydroxyacetone using 2-picoline·borane and reductive amination of core peptide
G with side chain H using t-BuNH2·borane complex.
