| 摘要 |
PROBLEM TO BE SOLVED: To easily obtain an optically active diol having high optical purity by reducing a diketone with an asymmetric reducing agent composed of a borane and a specific optically active amino alcohol having a substituted silyloxy group at 3-position. SOLUTION: The objective optically active diol of formula III is produced by reducing a diketone of formula I (R<1> to R<3> are each independently H, a lower alkyl, a lower alkoxy or a halogen) with an asymmetric reducing agent composed of an optically active amino alcohol of formula II (R<5> to R<7> are each independently H, a lower alkyl, etc., provided that R<5> to R<7> are not H at the same time; R<8> and R<9> are each II, a lower alkyl or a lower alkoxy; *represents asymmetric carbon atom) and a borane. The amount of the asymmetric reducing agent is 0.05-3mol, preferably 0.1-2mol in terms of the amino alcohol of formula II and 0.5-10mol, preferably 1-10mol in terms of baron based on the diketone of formula I. |
