Structure Determination and Total Synthesis of Bottromycin A2: A Potent Antibiotic against MRSA and VRE

After 50 years of persistence the 12-membered cyclic skeleton of bottromycin A2 (3) has been confirmed by NMR experiments (HMBC), and the configurations of two tLeu residues have been estimated by conformation analysis and NMR experiments. Furthermore, the key step in the synthesis of 3 involves the mercury-mediated formation of the amidine of thioamide 1 and amine 2.