Total Syntheses of the Reported Structures of Curcusones I and J through Tandem Gold Catalysis

Abstract

Total syntheses of the reported structures of the rhamnofolane diterpene natural products curcusones Iand Jin racemic form were achieved. The synthetic strategy features an ovel tandem gold-catalyzed furan formation and furanallene [4+ +3] cycloaddition to build the 5,7-fused ring system with an oxa-bridge in one step,and astereoselective exo-Diels-Alder reaction to form the 6-membered ring. The newly developed tandem gold catalysis is quite general and can be scaled up.O ur syntheses suggest that structural revisions of curcusones Ia nd Jare needed.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.