Stereoselective Alkylation of Glycine Units in Dipeptide Derivatives: “Chirality Transfer” via a Pivalaldehyde N,N-Acetal Center

Robin Polt, Dieter Seebach

Research output: Contribution to journalArticle

49 Scopus citations

Abstract

Dipeptide esters (of glycylglycine, glycylalanine, alanylglycine) and aldehydes (isobutyraldehyde, pivalaldehyde, benzaldehyde) are condensed to (4-oxoimidazolidin-3-yl)acetates and -propionates (1–3). Lithium enolates of these derivatives are generated (deprotonation of the ring and/or side-chain α-carbonyl positions) with LDA, LDA/LiBr, or LHMDS and alkylated with high diastereoselectivity (products 4, 6, 7). Dipeptides of either R,R or S,S configuration can be prepared from the glycine-containing precursors. Surprising proton-transfer effects (Schemes VI-IX, XII) are interpreted as a consequence of “intimate complexation” among LDA, LiBr, lithium enolates, and diisopropylamine.

Original languageEnglish (US)
Pages (from-to)2622-2632
Number of pages11
JournalJournal of the American Chemical Society
Volume111
Issue number7
DOIs
StatePublished - Mar 1989
Externally publishedYes

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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