Chemoenzymatic preparation of fluorine-substituted β-lactam enantiomers exploiting Burkholderia cepacia lipase

Both enantiomers of fluorinated and non-fluorinated 4-phenyl-2-azetidinones are prepared in high enantiopurities (ee 99%) by a chemoenzymatic method, using a double resolution technique to N-hydroxymethylated β-lactams in the presence of Burkholderia cepacia lipase as the source of enantiopurity. N-Deprotections yield the β-lactam enantiomers from the corresponding hydroxymethylated counterparts using KMnO4 in a mixture of acetone and water.