aurachins includes the intriguing migration of the prenyl group by a pinacol‐type rearrangement. In vitro analysis of AuaGH revealed that these enzymes catalyze epoxidation coupled with semipinacolrearrangement (see scheme) and ketoreduction. Thus, the AuaGH system was revealed to be a novel enzymatic system for establishing semipinacolrearrangements.