A Nine-Step Total Synthesis of (-)-Platencin

摘要

Within 1 year, platencin, a recently discovered antibiotic, has become a highly competitive synthetictarget, due to its promising bioactivity and its unusual complex molecular architecture. Herein, a particularlyconcise total synthesis of platencin starting from inexpensive perillaldehyde is described. The key featuresof this approach are (1) a highly diastereoselective Diels—Alder reaction with Rawal' s diene—formingthe first all-carbon quaternary center, (2) a ring-closing metathesis to generate the strained tricylic skeleton,(3) a hydration/dehydration strategy to efficiently shift the endocyclic alkene to the exoposition, and (4)a 1,4-addition of a hindered ketone enolate to methyl acrylate to create the second all-carbon quaternarycenter. In view of the brevity (nine linear steps) and the overall yield of 10%, our synthesis comparesfavorably with all the previous ones.