Determination of the absolute stereochemistry at the C16 orthoester of everninomicin antibiotics; a novel acid-catalyzed isomerization of orthoesters

Article abstract of DOI:10.1016/S0040-4039(97)10178-2

The absolute stereochemistry at C16 orthoester center of Ziracin (1) was unequivocally established via a novel acid-catalyzed orthoester isomerization. Structures of the resulting isomers 2 and 3 were determined by chemical degradation and extensive spectroscopic analyses. This novel isomerization was successfully extended to other related everninomicins (11-13), thus completing the entire structural assignment of everninomicin antibiotics.