The Claisenrearrangement of (S)-1-buten-3-yl propanoate via the (E)- and (Z)-silylketene acetal has been shown to proceed with 96–100% of 1,4-chirality transfer to afford (E,R)- and (E,S)-2-methyl-4-hexenoic acid, respectively. The variation in sense and degree with solvent and silylating agent is discussed on mechanistic grounds.