New fast and practical method for the enantioselective synthesis of α-vinyl, α-alkyl quaternary α-amino acids

Article abstract of DOI:10.1016/j.tetasy.2007.12.012

We describe a fast and practical enantioselective synthesis of (S)-N-Cbz-α-vinyl, phenylalanine, suitable for the preparation of different N-Cbz-α-vinyl aminoacids of both configurations. The new protocol exploits a Wittig reaction on highly enantiomeric enriched N-Cbz-α-formyl-α-alkyl amino esters, readily accessible from (l)-serine through a stereoselective alkylation of Seebach's oxazolidine, carried out with a significant improvement of the previously reported method. The synthetic scheme is suitable for gram scale preparation of the desired product with a 94% ee.