Asymmetric synthesis of the anticoccidial antibiotic diolmycin A1. Determination of absolute stereochemistry

An asymmetric total synthesis of diolmycin A1 (1), a recently discovered anticoccidial antibiotic, has been achieved in six steps from 2-(4-hydroxyphenyl)ethanol. The natural product comprises an unusual ca. 4:1 mixture of enantiomers; the synthesis defined the (11R,12S) absolute configuration of the predominant (−) antipode.