Efficient resolution of rac-2-cyano-2-methyl-3-phenylpropanoic acid. An appropriate starting material for the enantioconvergent synthesis of (S)-α-methylphenylalanine on a large laboratory scale
✍ Scribed by Ramón Badorrey; Carlos Cativiela; Marı́a D. Dı́az-de-Villegas; José A. Gálvez
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 369 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0957-4166
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✦ Synopsis
A large laboratory scale synthesis of (S)-a-methylphenylalanine from benzaldehyde and methyl cyanoacetate has been developed. The synthesis is based on the following sequence: (i) preparation of racemic 2-cyano-2-methyl-3-phenylpropanoic acid, (ii) resolution of the enantiomers by crystallisation using norephedrine, and (iii) development of an efficient enantioconvergent synthesis of (S)-a-methylphenylalanine from enantiopure (S)-and (R)-2-cyano-2-methyl-3-phenylpropanoic acid. The simplicity of the experimental procedures, which avoid low temperature reactions, the need for an inert atmosphere and column chromatography, combined with the use of inexpensive and readily available reagents make this method synthetically very attractive.