An efficient route to all stereoisomeric enantiopure 6-amino-3-alkyl-3-azabicyclo[3.2.1]octane-6-carboxylic acids

An efficient method is described for preparing the four stereoisomers of 6-amino-3-azabicyclo[3.2.1]octane-6-carboxylates by using (R)-1-phenylethylamine as the chiral-inducing moiety. A series of N-3-alkyl compounds are prepared by using a one-pot deprotection-alkylation method starting from these compounds.