Asymmetric synthesis of α-amino aldehydes from sulfinimine (N-sulfinyl imine)-derived α-amino 1,3-dithianes. Formal synthesis of (−)-2,3-trans-3,4-cis-dihydroxyproline

Hydrolysis of sulfinimine-derived N-sulfinyl α-amino 1,3-dithianes with aqueous 1,3-dibromo-5,5-dimethylhydantoin affords the corresponding N-tosyl α-amino aldehydes in good yield and high enantiomeric purity. These aldehydes can be reduced to amino alcohols and undergo the Wittig reaction to give allylic amines without epimerization. The utility of this methodology is illustrated in a formal synthesis of (−)-2,3-trans-3,4-cis-dihydroxyproline.