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- Title
Alkylation of Imidazolidinone Dipeptide Derivatives: Preparation of Enantiomerically Pure Di- and Tripeptides by 'Chirality Transfer' via a Pivalaldehyde N,N-Acetal Center. Preliminary Communication.
- Authors
Polt, Robin; Seebach, Dieter
- Abstract
Glycylglycine, glycyl-( S)-alanine, and ( S)-alanylglycine esters are cyclized through pivalaldehyde imines to give dipeptide-derived 3-(benzyloxycarbonyl)-2-( tert-butyl)-5-oxoimidazolidine-1-acetates 1- 3. These are alkylated diastereoselectively by Li-enolate formation and addition of alkyl bromides or iodides (products 4- 6). Starting from ( S)-alanine and glycine, ( S)-alanyl-( S)-alanine or ( R)-alanyl-( R)-alanine, and ( R)-alanyl-( R)alanyl-( S)-alanine- have thus been prepared, with the ( tert-butyl)-substituted N,N-acetal center playing the role of a pivot or lever for diastereoselective formation of new stereogenic centers under kinetic or thermodynamic control.
- Publication
Helvetica Chimica Acta, 1987, Vol 70, Issue 7, p1930
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/hlca.19870700727