Epimers vs. inverse epimers: the C-1 configuration in alnumycin A1

Abstract

The determination of whether two stereoisomers constitute an epimeric pair or if they differ in their configuration at all stereogenic centers bar one can be deceptive, and even more problematic than just absolute configuration determination per se. The latter stereochemical relationship is hereby defined as a pair of inverse epimers and is exemplified by alnumycin A1 to introduce the concept.