Synthesis of enantiomers of exo-2-norbornyl-N-n-butylcarbamate and endo-2-norbornyl-N-n-butylcarbamate for stereoselective inhibition of acetylcholinesterase.

The acetylcholinesterase inhibition by enantiomers of exo- and endo-2-norbornyl-N-n-butylcarbamates shows high stereoselelectivity. For the acetylcholinesterase inhibitions by (R)-(+)- and (S)-(-)-exo-2-norbornyl-N-n-butylcarbamates, the R-enantiomer is more potent than the S-enantiomer. But, for the acetylcholinesterase inhibitions by (R)-(+)- and (S)-(-)-endo-2-norbornyl-N-n-butylcarbamates, the S-enantiomer is more potent than the R-enantiomer. Optically pure (R)-(+)-exo-, (S)-(-)-exo-, (R)-(+)-endo-, and (S)-(-)-endo-2-norbornyl-N-n-butylcarbamates are synthesized from condensations of optically pure (R)-(+)-exo-, (S)-(-)-exo-, (R)-(+)-endo-, and (S)-(-)-endo-2-norborneols with n-butyl isocyanate, respectively. Optically pure norborneols are obtained from kinetic resolutions of their racemic esters by lipase catalysis in organic solvent.