Biomimetic Approach Toward Enterocin and Deoxyenterocin

Enterocin (vulgamycin) is a structurally
remarkable natural product
with significant antibiotic activity. The synthesis of a linear polyketide
resembling a biosynthetic precursor was achieved using an unusual
acyloin reaction. A diazo group was introduced as a protecting group
for an enolizable ketone. We were unable to bring about the envisioned
biomimetic aldol addition cascade and gained insights into the feasibility
of this process by DFT calculations. As an alternative approach to
enterocin, we developed a Cu-catalyzed intramolecular cyclopropanation
followed by a MgI2-induced fragmentation to install the
2-oxabicyclo[3.3.1]­nonane core of the natural product.