Synthesis and biological activity of enantiomers of a conformationally restricted muscarone analog

Abstract A short and efficient synthesis of both enantiomers of 2,8-dimethyl-1-oxa-8-azaspiro[4.5]-decan-3-one is described. The biological activity of the racemate resides predominantly in the S-enantiomer. While the S-isomer is a full M2-agonist, the R-isomer is devoid of M2 efficacy.