To obtain an optically active 3-pentyn-2-ol useful as a synthetic intermediate for pharmaceuticals, etc., on an industrial scale in high reaction yield and optical yield at a low cost using a catalytic amount of asymmetric source by using a metallic catalyst containing a specific ligand.
The objective compound of formula III is produced by the hydrogen-transfer asymmetric reduction of (A) 3-pentyn-2-on of formula I with formic acid in the presence of a catalyst comprising a combination of (B) a compound of a group VIII metal of the periodic table (preferably a ruthenium compound) and (C) an asymmetric ligand of formula II [R3 and R4 are each a (substituted)alkyl, an aryl or an aromatic ring; R5 and R6 are each H, a lower alkyl, an acyl or the like; the mark * represents asymmetric carbon atom] and a base (preferably a tertiary organic amine). The reaction is preferably carried out by using acetonitrile or dimethylformamide as a reaction solvent.
WATANABE MICHI
ICHIKAWA SHUJI
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