Anti-Dioxylation of Cyclohex-4-ene-1,2-diamine Derivatives: Asymmetric Routes to Hydroxy- and Amino-Substituted Cyclohexane and 7-Azanorbornane

The highly diastereoselective anti-dioxylation of (1R,2R)-1,2-bis[(1S)-phenylethylamino]cyclohexene was accomplished through epoxidation of the double bond with m-chloroperbenzoic acid (mCPBA) in the presence of a sulfonic or trihaloacetic acid and ring opening of the epoxide in situ in the presence of sulfonate or carboxylate anions. The two procedures, after basic quenching and reductive removal of the N-substituents, provide stereoselective access to 2-exo-5-endo-5-amino-7-azabicyclo[2.2.1]heptan-2-ol and 4,5-diaminocyclohexane-1,2-diol, respectively. The different outcomes are explained by differing chair conformations of the protonated diamine-epoxide intermediates, which undergo ring opening through a preferred anti-diaxial mechanism.