Chemoenzymatic synthesis of (–)-carbovir utilizing a whole cell catalysed resolution of 2-azabicyclo[2.2.1]hept-5-en-3-one

The resolution of (±)-2-azabicyclo[2.2.1]hept-5-en-3-one (3), a versatile intermediate in the synthesis of carbocyclic nucleosides, is described; both optical forms of the lactam have been obtained in very high optical purity (> 98% enantiomeric excess) in rapid, facile, large-scale biotransformation processes using whole cell catalysts and the laevorotatory enantiomer has been converted into (–)-carbovir.