Synthesis of capsidiol biosynthetic intermediates and their fluoro and aza analogs

ORGN 246

Yuxin Zhao, Yinghua Jin, and Robert M. Coates. Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S Mathews Ave., Urbana, IL 61801
Capsidiol is a bicyclic sesquiterpene diol with antifungal activity found in many solanaceous species. Because of its phytoalexin function and unusual structure, capsidiol has attracted intense research interest. Biosynthetically, capsidiol is derived from farnesyl pyrophosphate (FPP) by isoprenoid pathway via 5-epi-aristolochene (EA). Research is focused on the synthesis of both natural and non-natural sesquiterpenes as mechanism-based inhibitors or active site probes for the study of capsidiol biosynthesis and the corresponding enzymatic engineering. This report details the synthesis of a series of capsidiol biosynthetic intermediates and analogs. 1-Deoxycapsidiol and 3-deoxycapsidiol were prepared from capsidiol via selective substitution and reduction. EA and two other new sesquiterpenes were synthesized from the two deoxycapsidiols. The two possible fluoro inhibitors, 2-F-FPP and 6-F-FPP, were also prepared. Finally, the progress in the synthesis of a macrocyclic aza analog was reported.