Total Synthesis and Structural Revision of Monocillin VII.

The first asymmetric total synthesis of macrolactone monocillin VII and its C-10' epimer was achieved starting from a known chiral pure epoxide in 16 longest linear sequences. The present synthesis highlights the macrolactone formation involving an alkyne-dicobalt carbonyl complex under De Brabander's conditions followed by an unexpected regioselective hydration. The asymmetric total synthesis resulted in the revision of the configuration at C10' and reassignment of the absolute configuration of the natural product.