Abstract: An efficient asymmetric catalysis is developed for the glyoxylate-ene reaction to afford the a-hydroxy esters of biological and synthetic importance. The key to the success is the use of the chiral titanium complex prepared in situ from (i-Pr0) 2TiX2 (X= CI or Br) and the (R)-or (S)-binaphthol in the presence of molecular sieves (MS 4A). The presence of the molecular sieves (zeolite) is clarified to facilitate the alkoxy-ligand exchange reaction. ...