Convergent Synthesis of Kibdelone C

Abstract

The synthesis of kibdelone C, a polycyclic natural xanthone isolated from a soil actinomycete, was achieved through a convergent approach. A 6π-electrocyclization was applied to construct the highly substituted dihydrophenanthrenol fragment (B-C-D ring). InBr-promoted lactonization was employed to build the isocoumarin ring, which served as a common precursor for the formation of isoquinolinone ring (A-B ring). A key DMAP-mediated oxa-Michael/aldol cascade reaction was developed to install the tetrahydroxanthone fragment (E-F ring). This approach provides a new solution to prepare its derivatives and structurally related natural products.

Asymmetric Total Synthesis of the Complex Polycyclic Xanthone FD‐594

“…We aimed to achieve the first total synthesis of FD‐594 ( 1 ) as part of our on‐going interest in the total synthesis of bioactive polycyclic natural products and their medicinal chemistry . In previous work, we constructed tetrahydroxanthones using photo‐induced C−O bond formation, and synthesized dimeric xanthone ascherxanthone A as well as polycyclic xanthone kibdelone C ( 4 ) . Herein, we report a new strategy of asymmetric dihydroxylation followed by oxidative cyclization to form the trans ‐9,10‐dihydrophenanthrene‐9,10‐diol core (Scheme B, I → II ).…”

Asymmetric Total Synthesis of the Complex Polycyclic Xanthone FD‐594

“…[16] In previous work, we constructed tetrahydroxanthones using photo-induced CÀO bond formation, [17] and synthesized dimeric xanthone ascherxanthone A [18] as well as polycyclic xanthone kibdelone C (4). [19] Herein, we report a new strategy of asymmetric dihydroxylation followed by oxidative cyclization to form the trans-9,10-dihydrophenanthrene-9,10-diol core (Scheme 1 B, I!II). We propose that II may serve as an advanced intermediate to prepare both FD-594 and biogenetically related kigamicins when followed by selective dehydroxylation of the C-6 hydroxyl group.…”

A Ag2CO3/TFA-catalyzed intramolecular annulation approach to imidazo[1,2-c][1,3]oxazin-5-one derivatives

“…1a). The second method involves transition-metal catalysts including Au, 14,22–24 Ag, 25–27 Pt, 28,29 In, 30 B, 31,32 Cu, 33–35 and Fe 36,37 providing a competition between 5- exo-dig and 6- endo-dig cyclizations (Fig. 1b).…”