Process for asymmetric hydrogenation

A process for the preparation of a compound of the formula:

• where R3 is selected from the group consisting of:
• —NO2,
• —NH2,
• —NH—SO2-[4-trifluoromethylpyridin-2-yl],
• —N(—CH2-φ)2,
• —N(R3-1)(R3-2) where R3-1 and R3-2 are the same or different and are:
• —H,
• —CO—O—(t-butyl),
• —CO—O—CH2-φ,
• —CO—CH3,
• —CO-φ,
• —Cl
• —Br,
• —I,
• —OH,
• —O—SO2—CF3;
• where n is 0 or 1 with the provisos (1) that when n is 0 the R3 group must be in the meta position and (2) that when n is 1, one of R3 must be —Cl, —Br, —I, —OH or —O—SO2—CF3;
• where R4 is selected from the group consisting of Na+, K+, Li+, Cs+ and (R4-1)4N+ where R4-1 are the same or different and are CH3—, C2H5—, C4H9—, φ-CH2— and C8H17— which comprises hydrogenating a compound of the formula:
• the E-geometrical isomer thereof or a mixture of the Z- and E-isomers, where R3 and R4 are as defined above, in the presence of catalyst containing Rh, a chiral ligand with at least one phosphorous atom.