193673-85-7Relevant academic research and scientific papers
Process for making α,β-unsaturated carboxylic acids
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, (2008/06/13)
α, β-Unsaturated acids of the formula STR1 wherein R1 signifies C1 -C5 -alkyl and Ar signifies an aryl group which is optionally substituted by one or more substituents selected from the group consisting of halogen, phenyl, C1 -C5 -alkyl, C1 -C5 -alkoxy, perfluorinated C1 -C5 -alkyl or perfluorinated C1 -C5 -alkoxy can be obtained from new or known compounds of the formula STR2 Compounds I can be converted by asymmetric hydrogenation into corresponding optically active saturated acids.
Practical synthesis of (S)-2-(4-fluorophenyl)-3-methylbutanoic acid, key building block for the calcium antagonist Mibefradil
Crameri, Yvo,Foricher, Joseph,Scalone, Michelangelo,Schmid, Rudolf
, p. 3617 - 3623 (2007/10/03)
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.
