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.

Summary of main observation and conclusion A titanium‐promoted intramolecular photoenolization/Diels–Alder (PEDA) reaction was developed to construct the core skeleton of aromatic polycyclic terpenoids bearing an all‐carbon quaternary center on the benzylic position. Titanium(IV) isopropoxide [Ti(Oi‐Pr)4] plays a key role during the photo cycloaddition, which may help to accelerate the interaction between dienophile and the stereo‐hindered diene species as well as control the diastereoselectivity. This photolysis provides a new solution for the stereospecific formation core structures of aromatic abietane diterpenoids and sesquiterpenoids, which have multiple functional groups for the further transformations. As a synthetic application, it was successfully used in the synthesis of indolosesquiterpenoid mycoleptodiscin A.

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.

A new approach was developed to achieve the asymmetric total synthesis of (+)-PD-116740, an angucyclinone from the actinomycete isolate (WP 4669). A sequence of asymmetric dihydroxylation followed by oxidative cyclization was applied to stereoselectively construct the core trans-9,10-dihydrophenanthrene-9,10-diol B–C–D ring. A new Cu salt Cu­(OH)­OTf·NMI2 was found to be the best oxidant to induce the oxidative coupling and phenol oxidation.