%0 Journal Article
%T Construction of a 6/5/9-membered tricyclic structure of cladiellins via radical-polar crossover reaction
%J -
%D 2019
%R https://doi.org/10.1038/s41429-019-0150-7
%X A three-component coupling reaction of structurally simple 6¨C8 was successfully applied for expeditious synthesis of the 6/5/9-membered tricyclic structure 3 of cladieunicellin D (1) and klysimplexin U (2). Upon treatment with the Et3B/O2 reagent system, ¦Á-alkoxyacyl telluride 6, six-membered enone 7, and (Z)-4-hexenal (8) were linked in one pot to provide the densely functionalized 5 via sequential decarbonylative radical generation, radical addition, boron enolate formation, and intermolecular aldol reaction. Subsequent Lewis acid-promoted reductive etherification and SiO2-induced C10-epimerization gave rise to the cis-fused five-membered ether of 4. Finally, cyclization of the nine-membered ring was achieved by the ring-closing metathesis reaction, giving rise to 3. Compound 3 possesses the six stereocenters of 1 and 2, and would thus serve as an advanced intermediate for their total syntheses
%U https://www.nature.com/articles/s41429-019-0150-7