Divergent Total Syntheses of Illicium Sesquiterpenes through Late-Stage Skeletal Reorganization

• DOI: 10.1021/jacs.3c06442
• Publication Date: 2023-08-10T21:06:45Z
• Authors: Pengfei Fu; Tao Liu; Yang Shen; Xin Lei; Tianjie Xiao; Peng Chen; Dongsheng Qiu; Zhen Wang; Yandong Zhang
• Keywords: Molecular Structure; Cyclization; Humans; Oxidation-Reduction; Sesquiterpenes; Illicium

We disclose unified, protecting-group-free, bioinspired divergent total syntheses of eight allo-cedrane and seco-prezizaane Illicium sesquiterpenes and formal syntheses of five anislactone sesquiterpenes. The efficiency of our approach derives from rapid access to the 15-carbon tricyclic carboxylic acid through cationic epoxide-ene cyclization and HAT oxygenation, transformation of this intermediate into three distinct tricyclic precursors via Lewis acid-mediated skeletal reorganizations, subsequent programmed oxidation level enhancement, and a biomimetic oxidation-initiated skeletal rearrangement cascade. Consequently, we created a synthetic correlation map of the three most prevalent Illicium sesquiterpene families.