Slow addition of 2-[N-(alkoxycarbonyl)amino] aldehydes to mixtures of [V2Cl3(THF)(6)](2)[Zn2Cl6] and aliphatic aldehydes gave syn,syn-3-[N-(alkoxycarbonyl)amino] 1,2-diols in good yield and high enantiomeric purity (>99:1). The alkyl group of the N-alkoxycarbonyl was shown to influence the yield : Me>allyl>Bn>t-Bu. Only the syn,syn diastereomer was observed (>20:1), except with N-Cbz-alaninal (10:1:1), O-benzyl-N-Cbz-serinal (7:1), and N-Cbz-prolinal (5:1 to 12:1). A new serinal derivative, N-Cbz-O-TBS-serinal, was cross coupled with n-pentadecanal to give a derivative of xylo-D-C-18-phytosphingosine.