PTC and organic bases–LiCl assisted alkylation of imidazolidinone–glycine iminic derivatives for the asymmetric synthesis of α-amino acids
摘要:
Iminic derivatives of (4R,5S)-1,5-dimethyl-4-phenylimidazolidin-2-one and glycine 4 have been highly diastereoselectively alkylated with activated alkyl halides or electrophilic olefins either under PTC conditions or in the presence of the strong organic bases DBU or BEMP at -20 degrees C in the presence of LiCl. Hydrolysis of the alkylated imino imides gave (S)-alpha-amino acids with recovery of the imidazolidinone chiral auxiliary. (C) 1998 Elsevier Science Ltd. All rights reserved.