(Z)-2-Methoxy-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-acrylic Acid → Aleglitazar

Participants

Reaction Steps

In an analogous manner to Example 10 but in the presence of (S)-phenylethylamine (2.29 mmol) instead of NaOH as a base, 5 g (11.48 mmol) of (Z)-2-methoxy-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-acrylic acid were asymmetrically hydrogenated in 37 ml methanol/dichloromethane (3:2) in the presence of 0.93 mg of [Ru(OAc)2((S)-TMBTP)] (S/C molar ratio 10'000) under 30 bar of hydrogen for 4 h at 40°, then 2 h at 60° h to reach 99.9% conversion. Rotary evaporation of the reaction mixture afforded quantitatively (S)-2-methoxy-3-{4-[2-(5-methyl-2-phenyl-oxazol-4-yl)-ethoxy]-benzo[b]thiophen-7-yl}-propionic acid of 91.8% ee with 99.4% purity (HPLC area). In analogy to example 13, the experiments described in table 1 have been carried out with different substrate-to-catalyst ratios.

Provenance & Evidence