I. Asymmetric Alkylation Reactions of Chiral Imide Enolates. II. Efforts Directed Toward the Total Synthesis of (+)-Macbecin I

Citation

Ennis, Michael Dalton (1983) I. Asymmetric Alkylation Reactions of Chiral Imide Enolates. II. Efforts Directed Toward the Total Synthesis of (+)-Macbecin I. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/pqm8-7286. https://resolver.caltech.edu/CaltechTHESIS:09032019-124939824

Abstract

The preparation of chiral N-acyl oxazolidones 6 and 7 from readily available amino acid precursors is described. Reaction of the alkali metal enolates derived from these chiral imides with alkyl halides and acid chlorides exhibit high levels of kinetic diastereoselection. Chromatographic enrichment

[chemical structure; see abstract in scanned thesis for details]

affords alkylated and acylated products of ≥ 99:1 diastereomeric purity. Non-destructive cleavage of the chiral auxiliary is accomplished by a variety of means to afford optically active products.

The use of chiral imides 6 and 7 in the synthesis of the ansa-antibiotic macbecin-I (1) is described. The synthesis makes use of the iterative application of highly stereoregulated aldol condensations of N-acyl oxazolidones for the construction of the ansa-bridge of 1. This project has culminated in the preparation of the advanced acyclic intermediate 46.

[Chemical structures; see abstract in scanned thesis for details.]

Thesis Files