Asymmetric titanium-catalysed Michael addition of O-benzylhydroxylamine to alpha,beta-unsaturated carbonyl compounds: Synthesis of beta-amino acid precursors

L Falborg, KA Jorgensen

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Abstract

A new titanium-catalysed Michael type addition of O-benzylhydroxylamine to alpha,beta-unsaturated N-acylated 1,3-oxazolidinones giving beta-amino acid precursors has been developed. The reaction is catalysed by TiX(2)-TADDOLate and TiCl2-BINOLate complexes and good conversions with enantiomeric excesses up to 42% were obtained with the application of 10 mol% of the catalyst. In order to determine the absolute stereochemistry of the enriched enantiomer one of the products, 3-(3-benzyloxyaminobutanoyl)-1,3-oxazolidin-2 was converted into methyl 3-benzoylaminobutanoate. Based on the absolute stereochemistry of the Michael type addition product the mechanism for the addition step is discussed, as well as the structure of the active intermediate.

OriginalsprogEngelsk
TidsskriftOrganic & Biomolecular Chemistry
Nummer23
Sider (fra-til)2823-2826
Antal sider4
ISSN0300-922X
StatusUdgivet - 7 dec. 1996

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