Yvo Crameri, J. Foricher, M. Scalone
Nov 13, 1997
Citations
0
Influential Citations
21
Citations
Journal
Tetrahedron-asymmetry
Abstract
Abstract A short, technically feasible route was developed for the synthesis of (S)2-(4-fluorophenyl)-3-methylbutanoic acid (S)- 2 with an overall yield of 80% starting from 4-fluorophenylacetic acid. Asymmetric hydrogenation of the easily accessible unsaturated acid 3 in the presence of ruthenium(II) carboxylato complexes containing chiral atropisomeric diphosphines afforded (S)- 2 in up to 94% ee. The ee of (S)- 2 was upgraded to 98% by crystallization of its sodium salt. The same protocol was also applied to the synthesis of (S)-2-(4-chlorophenyl)-3-methylbutanoic acid.