Stereoselective Synthesis of (+)--Conhydrine from R-(+)-Glyceraldehyde

Scheme 2

Reagent and conditions: (a) CH₂=CHCH₂NH₂, Et₂O, anhyd.MgSO₄, 0°C to rt, 3 h, 82%; (b) CH₂=CHCH₂Br, Zn, THF, aq.NH₄Cl, 0°C to rt, 10 h, 80%.