Asymmetric Total Synthesis of (+)-Aplysiasecosterol A
Total Synthesis of Aplysiasecosterol A.
J. Am. Chem. Soc. 2018;
17 September 2018 (online)
Key words(+)-aplysiasecosterol A - Hara–Roush allylation - Zweifel–Evans olefination - HAT-based radical cyclization - desymmetrization
The first total synthesis of (+)-aplysiasecosterol A is reported by Li and co-workers in 14 steps (longest linear sequence). Key features include an iron-mediated HAT radical cyclization, an asymmetric allylation, and a Zweifel–Evans olefination.
Recognition of hidden symmetry in the core of the target structure allowed the clever application of a desymmetrization strategy starting from achiral dione A. Advanced intermediate P was assembled from bromide H and aldehyde O. Radical cyclization and deprotection led to the natural product.