Chlorocyclopentadienyl[(4S,5S)-2,2-dimethyl-α,α,α′,α′-tetraphenyl-1,3-dioxolane-4,5-dimethanolato]titanium

A novel highly enantioselective allyl-transfer reagent. Excellent regio-, diastereo-, and enantioselectivities (usually >95% ee, >95% de) are obtained for the addition of allyl nucleophiles to aldehydes. Although this reagent is used in stoichiometric amounts, the chiral ligand and monocyclopentadienyltitanium trichloride can be easily recovered.