Schöllkopf method

[3][4][5] In it glycine is a substrate, valine a chiral auxiliary and the reaction taking place an alkylation.

The next step decides the stereoselectivity of the method: One face of the carbanionic center is shielded by steric hindrance from the isopropyl residue on valine.

With valine Schöllkopf selected the natural proteinogenic amino acid with the largest non-reactive and nonchiral residue in order to achieve the largest possible stereoselectivity, generally speaking enantiomeric excess of over 95% ee is feasible.

With the Schöllkopf method all amino acids can be synthesised when a suitable R-I reagent is available.

The method is limited to the laboratory for the synthesis of exotic amino acids.