An Efficient and Highly Stereocontrolled Route to Bulgecinine Hydrochloride

(−)-Bulgecinine is a nonproteinogenic amino acid component present in bulgecins A, B, and C,
antibiotic glycopeptides derived from Pseudomonas acidophila and Pseudomonas mesoacidophila.
In combination with β-lactam antibiotics, bulgecins exihibit a unique synergistic antibacterial
activity against various Gram-negative microorganisms. Utilizing d-serine as a chiral template
and employing a highly regio- and stereoselective intramolecular amidomercuration-oxidation
protocol in the key pyrrolidine ring forming step, an efficient total synthetic route to enantiopure
bulgecinine is reported herein.