Process for producing optically active β-amino acid derivatives

A process for producing an optically active β-amino acid derivative of the formula (2):

• wherein R1 and R2 are each independently a hydrogen atom, a hydrocarbon group which may be substituted, an acyl group which may be substituted, an alkoxycarbonyl group which may be substituted, an aryloxycarbonyl group which may be substituted, an aralkyloxycarbonyl group which may be substituted, an alkoxy group which may be substituted, an aryloxy group which may be substituted, an aralkyloxy group which may be substituted and a heterocyclic group which may be substituted;
• R3 is a hydrogen atom, an alkoxy group which may be substituted, an acyloxy group which may be substituted, an aralkyloxy group which may be substituted, a hydroxy group and a hydrocarbon group which may be substituted;
• R4 is an alkoxy group which may be substituted, an aryloxy group which may be substituted, an aralkyloxy group which may be substituted, a hydroxy group, —NRaRb [wherein Ra and Rb are each independently a hydrogen atom, a hydrocarbon group which may be substituted and an acyl group which may be substituted, —SO2A1 (wherein A1 is a hydrocarbon group which may be substituted or a substituted amino group), or —COORc (Rc is a hydrocarbon group which may be substituted)] or a heterocyclic group which may be substituted, and R1 and R2, or R2 and R3 each may combine to form a ring;
• with the proviso that when R1=R2, then R3 is a hydrocarbon group which may be substituted;
• Q is a group formed by removing a hydrogen atom from an amine;
• and
• * indicates an asymmetric carbon atom;
• or a salt thereof,
• which comprises reacting an α,β-unsaturated carboxylic acid derivative of the formula (1):
• wherein R1 to R4 are each the same as mentioned above, with an amine or a salt thereof, in the presence of a chiral catalyst,
• wherein the chiral catalyst is a chiral transition-metal complex of the formula (5):
• [M2LpAq]y+(Z−)y (5)
• wherein L is a chiral ligand;
• Z− is a counter anion;
• A is an anionic ligand selected from the group consisting of a hydroxy group, an amide group, an alkoxy group and a halogen atom;
• M is a transition metal;
• y is 0 or 2;
• q is 2;
• p is 2 or 4, or of the formula (6):
• MLrBs(Z−)c (6)
• wherein L is a chiral ligand;
• Z− is a counter anion;
• B is a water molecule or a neutral ligand;
• M is a transition metal;
• r is 1 or 2;
• s is 0, 1, 2, 4 or 6;
• c is0, 1 or 2, and in the presence of an acid.