Abstract: An object of the present invention is to provide a further more effective process for preparing a certain optically active compound including an optically active 1-acetyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline. The present invention provides a process for an optically active compound represented by formula (3) (wherein R5 represents a hydrogen atom etc., R6 and R7 each independently represents a hydrogen atom, etc., R8 represents a C1-C6 alkyl group, and R9, R10 and R11 each independently represents a hydrogen atom, etc. The carbon atom with a symbol of the asterisked “*” represents an asymmetric carbon atom), which comprises a reacting a compound represented by formula (2) (wherein R5, R6, R7, R8, R9, R10, and R11 has the same meanings as the above) with hydrogen in the presence of asymmetric cobalt complex.

Abstract: Compound (1) is useful as a catalyst since compound (III) can be obtained by reacting compound (I) with compound (II) in the presence of compound (I). In particular, an optically active substance of compound (III) can be produced by using compound (I) which is optically active.

Abstract: Compound (1) is useful as a catalyst since compound (III) can be obtained by reacting compound (I) with compound (II) in the presence of compound (I). In particular, an optically active substance of compound (III) can be produced by using compound (I) which is optically active.

Abstract: Compound (1) or a salt that is useful as an intermediate for the production of a medicine, an agrochemical or the like can be produced by a process including the following steps: (A) reacting an aldehyde (2) with nitromethane to produce a nitroaldehyde; (B) reacting the nitroaldehyde with an alcohol to produce a nitroacetal; (C) reducing the nitroacetal to produce an aminoacetal; (D) protecting an amino group in the aminoacetal to produce a protected aminoacetal; (E) treating the protected aminoacetal with an acid and subsequently with a base and then reacting the resultant product with a cyanating agent to produce a nitrile; (F) hydrolyzing the nitrile to produce a protected amino acid; and (G) substituting a group R5 in the protected amino acid by a hydrogen atom and protecting a carboxyl group therein.