Substrate-controlled titanium-mediated aldolreactionsfrom (S)-4-benzyloxy-3-methyl-2-butanone provide satisfactory levels of 2,5-syn asymmetric induction if they are carried out in the presence of a second equivalent of TiCl4. Such reactions give high yields and excellent diastereoselectivity with a wide array of achiral and chiral aldehydes without needing other sources of chirality. This procedure