| 摘要 |
PURPOSE:To obtain an optically active cyanohydrin in excellent yield and excess ratio of enantiomers using an inexpensive catalyst, by asymmetrically cyanogenating an aldehyde in the presence of a titanic acid ester of an optically active tartaric acid derivative. CONSTITUTION:An aldehyde is reacted and asymmetrically cyanogenated with a cyanogenating agent in the presence of an optically active titanic acid ester formed from a tetraalkyl titanate and an optically active tartaric acid deriva tive. The above-mentioned cyanogenation reaction is carried out in a solvent, e.g. halogenated hydrocarbon based solvent such as methylene chloride, etc., at -40-+60 deg.C to afford the aimed substance. A trialkylsilyl cyanide or hydro gen cyanide is used as the cyanogenating agent. The resultant compound is useful as a precursor for alpha-hydroxyl acids or beta-amino-alcohols, intermediate for synthetic pyrethroids for synthesizing optically active physiologically active substances, e.g. medicines, agricultural chemicals, etc.
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