Total Synthesis of Viridin and Viridiol

The asymmetric total
synthesis of (−)-viridin and (−)-viridiol,
antifungal metabolites, was achieved in 17 and 18 steps from a commercially
available starting material. An intra­molecular [3+2] cycloaddition
was applied to an easily available l-ribose
derivative in order to construct the highly substituted D ring containing
the key chiral cis-triol fragment. Co-catalyzed metal-hydride
H atom transfer (MHAT) radical cyclization was utilized to form the
C-ring and the all-carbon quaternary center at C-10. This convergent
strategy provides a scalable approach to prepare viridin and viridiol
for biological studies.