| 摘要 |
PURPOSE:To obtain a Cram-form optically active hydroxy compound useful as a synthetic intermediate for brassinolide which is a plant growth hormone in high conversion and selectivity, by reacting an optically active acetal with an organometallic compound. CONSTITUTION:An acetal expressed by formula I (X is organic group; Y is <10C hydrocarbon group; m is 0 or 1) is reacted with an organometallic compound expressed by the formula R<1>-M [R<1> is Z-C=C- or CH2=CH-CH2- (Z is <=10C alkyl, cycloalkyl or allyl); M is -SnR3<2> or -SiR3<2> (R<2> is 1-4C alkyl)] in an inert solvent, preferably a halogenated hydrocarbon, by increasing the reaction temperature gradually from -78 deg.C to -50 deg.C using dry ice-acetone, and an oxidizing agent is then reacted with the reaction mixture. The resultant reaction mixture is then hydrolyzed to afford the aimed compound expressed by formula II. |
