Method for producing optically active cycloalkylidenebisoxazoline compound and intermediate thereof

#The present invention relates to a method for producing an optically active cycloalkylidenebisoxazoline compound which is an important compound as a ligand of an asymmetric synthesis catalyst.

#An optically active cycloalkylidenebisoxazoline compound has been known as a component of copper bisoxazoline catalyst for asymmetric synthesis of an intermediate of agricultural chemicals and pharmaceuticals such as synthesized pyrethroid type insecticides. As methods for producing the optically active cycloalkylidenebisoxazoline compound, a method for reacting a 2,2-methylenebisoxazoline compound, which is obtained by the reaction of the corresponding optically active aminoalcohol and a malonimidate, with a alkyl dihalide such as 1,2-dibromoethane in the presence of a strong base (e.g. Non-patent document 1). However, it is not always satisfied in the overall yield.

#Non-patent document 1: J. Org. Chem., 65, 5875 (2000)

#The optically active aminoalcohol compound represented by the formula (1) (hereinafter, simply referred to as the optically active aminoalcohol (1)) will be illustrated.

#Examples of the C1-6 alkyl group represented by R1 or R2 in the optically active aminoalcohol (1) include a straight or branched chain C1-6 alkyl group such as a methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl and n-hexyl group.

#Examples of the optionally substituted phenyl group represented by R1 or R2 include a phenyl group which may be substituted with at least one selected from a C1-6 alkyl group and a C1-6 alkoxy group such as an unsubstituted phenyl group; a phenyl group substituted with the above-mentioned C1-6 alkyl group such as a 3-methylphenyl and 4-methylphenyl group; and a phenyl group substituted with a C1-6 alkoxy group (e.g. a methoxy, ethoxy, propoxy, butoxy, pentyloxy, and hexyloxy group) such as a 2-methoxyphenyl and 4-methoxyphenyl group.