Stereoselective total synthesis of (+)-streptazolin by using a temporary silicon-tethered RCM strategy

[GRAPHICS] A stereoselective total synthesis of (+)-streptazolin 1 was accomplished starting from readily available aminocyclopentenol (-)-7. The synthetic sequence highlights an intramolecular aldol condensation strategy to construct the piperidine core and a silicon-tethered ring-closing metathesis strategy to install the Z exocyclic ethylidene side chain of streptazolin. Separate protodesilylation and Tamao oxidation of a common intermediate 32 afforded streptazolin and the precursor for 13-hydroxystreptazolin. The overall yield for (+)-streptazolin 1 from aminocyclopentenol (-)-7 was 4.8% for a total of 16 steps.