This invention provides a method of preparing amine stereoisomers, which comprises stereoselectively reducing a sulfinylimine that bears on the sulfinyl group a residue of an alcohol, thiol or amine, or reacting a sulfinylimine stereoisomer that bears on the sulfinyl group a residue of an alcohol, thiol or amine with a source of a nucleophile, to afford a sulfinylamine stereoisomer, followed by contacting the sulfinylamine stereoisomer with a reagent suitable for the cleavage of a sulfur-nitrogen bond, to afford an amine stereoisomer. It also provides novel intermediates useful in the method, and the use of certain of the intermediates in the preparation of sulfoxide and sulfinylamine stereoisomers.