Asymmetric Total Synthesis of the Complex Polycyclic Xanthone FD‐594

A highly convergent approach was developed to achieve the first asymmetric and scalable total synthesis of FD‐594, a complex polycyclic xanthone natural product from Streptomyces sp. TA‐0256, in a longest linear sequence (LLS) of 20 steps. The trans‐9,10‐dihydrophenanthrene‐9,10‐diol fragment (B‐C‐D ring) was generated through a new strategy involving asymmetric dihydroxylation followed by Cu‐mediated oxidative cyclization. Late‐stage stereoselective glycosylation assembled the angular hexacyclic framework with a β‐linked 2,6‐dideoxy trisaccharide fragment. An asymmetric total synthesis of the complex polycyclic xanthone FD‐594 through a convergent and scalable approach is described. The trans‐9,10‐dihydrophenanthrene‐9,10‐diol fragment (B‐C‐D rings) was generated through a new strategy involving asymmetric dihydroxylation followed by Cu‐mediated oxidative cyclization. Late‐stage stereoselective glycosylation assembled the angular hexacyclic framework with a β‐linked 2,6‐dideoxy trisaccharide fragment.