Diastereoselective Alkylation of an Oxazolidinone Chiral Auxiliary

Asymmetric synthesis, the part of diastereoselective alkylation of a chiral auxiliary is an important tool in organic synthesis. In this work an α-methyl, non-natural amino acid (NNAA) building block equipped with a phthalimide group tail was prepared. This work describes the generation of the lithium enolate oxazolidin-2-ones chiral auxiliary derived from non-natural amino acid and quenching this enolate with 2-chloromethyl-isoindole-1,3-dione, to provide an α-methyl, non-natural amino acid (NNAA) building block equipped with a phthalimide group in good yield in multistep synthesis with no sign of any minor diastereomers. The identity of new compound was confirmed by 1H, 13C NMR and mass spectrometry. With this building block in hand, peptides can be produced for evaluation in a variety of therapeutic areas in drug discovery.