RESOLUTION AND USE IN α-AMINO ACID SYNTHESIS OF IMIDAZOLIDINONE GLYCINE DERIVATIVES

Article abstract of DOI:10.1016/S0040-4020(01)86036-1

The imidazolidinones (rac.-1 and rac.-2) obtained from pivalaldehyde and glycine amides are resolved efficiently by crystallization of diastereomeric ammonium salts with chiral acids (mandelates and a gulonate respectively).The free bases are acylated under Schotten-Baumann conditions to give enantiomerically pure 1-Bz-, 1-BOC-, 1-Z- or 1-formyl-2-t-butyl-3-methyl- or -3-benzyl-4-imidazolidinones.Diastereoselective alkylation of the 3-methyl derivatives (BMI) with a variety of electrophiles (LDA/THF -70 to +25 degC) gives trans-disubstituted imidazolidinones exclusively (3-22).Some of these are hydrolyzed by a procedure employing excess acidic ion exchange resin to give enantiomerically pure (R)- or (S)-amino acids.The procedure is compared with other methods of generating chiral glycine enolates.