To provide a method with which a 4-oxochroman-2-carboxylic acid derivative having an optical activity can inexpensively be synthesized and the economical and industrial production thereof can be carried out.
The method is carried out as follows. A 4-oxochromene-2-carboxylic acid derivative represented by general formula (I) (wherein, R1 means a hydrogen atom, a chlorine atom, a fluorine atom or a 1-6C alkyl group; and R2 means a hydrogen or a 1-6C alkyl group which may be substituted) is subjected to a reducing reaction with a siloxane derivative and a lower alcohol in the presence of an asymmetric metal complex formed from an optically active phosphine ligand and a copper salt or a tin salt and an alkali metal alkoxide in an organic solvent to thereby produce the optically active 4-oxochroman-2-carboxylic acid derivative represented by general formula (II) {wherein, R1 and R2 have each the same meaning as in general formula (I); and * means an asymmetric carbon}.
SUZUKI MASAAKI
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