Enantioselective Addition of Chiral Organotitanium Derivatives to Aldehydes

Alkoxy- and aryloxy-organotitanium compounds 2–4 derived from (S)-2-methyl-1-butanol, (R)-2-butanol, (-)-menthol, quinine, cinchonine, and (S)-1.1′-binaphthol are added to aromatic aldehydes to give optically active alcohols 5–10 in enantioselectivities of up to 88% e. e., with nucleophilic transfer of methyl, phenyl, and 1-naphthyl groups. The Tables 1–3 list the effects of varying the reagents, the substrates, and the reaction conditions of the new asymmetric synthesis.