For asymmetric synthesis of primary amines. A stereocentre is formed by direct addition of a Grignard nucleophile to a sulfinimide (sulphinimide) with a stereogenic sulfur centre. The sulfinimide is formed by condensation of the enantiomerically enriched sulfoxide (sulphoxide) with a carbonyl, such as an aldehyde or ketone. The transition state is thought to be a chelated ZimmermanTraxler type sixmembered ring.