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.

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Four stereoisomers of 2-norbornyl-N-n-butylcarbamates are characterized as the pseudo substrate inhibitors of cholesterol esterase. Cholesterol esterase shows enantioselective inhibition for enantiomers of exo- and endo-2-norbornyl-N-n-butylcarbamates. For the inhibitions by (R)-(+)- and (S)-(-)-exo-2-norbornyl-N-n-butylcarbamates, the R-enantiomer is 6.8 times more potent than the S-enantiomer. For the inhibitions by (R)-(+)- and (S)-(-)-endo-2-norbornyl-N-n-butyl-carbamates, the S-enantiomer is 4.6 times more potent than the R-enantiomer. The enzyme-inhibitor complex models have been proposed to explain these different enantioselectivities.

Enantiomers of cis,cis-decahydro-2-naphthyl-N-n-butylcarbamate show stereo-specific inhibition for acetylcholinesterase and butyrylcholinesterase. For both inhibition reaction, (2S,4aR,8aS)-cis,cis-decahydro-2-naphthyl-N-n- butylcarbamate is more potent than (2R,4aS,8aR)-cis,cis-decahydro-2-naphthyl-N-n-butylcarbamate. Optically pure (2S,4aR,8aS)-(-)- and (2R,4aS,8aR)-(+)-cis,cis-decahydro-2-naphthols are resolved by the porcine pancreatic lipase-catalyzed acetylation of decahydro-2-naphthols with vinyl acetate. Absolute configurations and the enantiomeric excess values of (2S,4aR,8aS)-(-)- and (2R,4aS,8aR)-(+)-cis,cis-decahydro-2-naphthols are determined from the (19)F NMR spectra of their Mosher's ester derivatives. We fail to resolve (2S,4aR,8aR)- and (2R,4aS,8aS)-trans,cis-decahydro-2-naphthols from the porcine pancreatic lipase-catalyzed acetylation of decahydro-2-naphthols with vinyl acetate.