Asymmetric synthesis of acetomycin

The synthesis of (-)-acetomycin, a highly functionalized γ-lactone with antitumor activity, was achieved in five steps with nearly complete enantioselectivity. The key step was realized by a large scale lipase R catalyzed esterification of 5-hydroxy-4-methyl-2(5H)-furanone providing (-)-(5R)-5-acetoxy-4-methyl-2(5H)-furanone with an e.e. of 99%