1989 年 47 巻 1 号 p. 11-19
Several chiral ligands were designed and synthesized which perform highly enantioselective asymmetric reactions of carbonyl compounds. Enantioselective reduction of ketones with lithium borohydride modified with N, N'-dibenzoylcystine (or N-benzoylcystein) and tent-butyl alcohol (or ethanol) provided optically active sec.-alcohols in up to 9293% e.e. Functionalized ketones such as α-, β- haloketones, α- and β-aminoketones, pyridyl ketones, and fl-ketoesters were also reduced enantioselectively to afford opticall active epoxides, oxetanes, aminoalcohols, pyridyl alcohols, and β-hydroxyesters in high e.e.'s. Chiral pyrrolidinylmethanols, N, N-dibutylnorephedrine (DBNE), chiral piperazine, and polymer bound N-alkylnorephedrine were efficient chiral catalysts of the enantioselective addition of dialkyl zincs to aldehydes. Alkylation of both aliphatic and aryl aldehydes afforded optically active sec-alcohols in high e.e.'s. Formylesters afforded optically active lactones. Enantioselective conjugate addition of dialkyl zincs to enones was catalyzed by chiral complex prepared from DBNE and Ni (acac) 2 or NiBr2.