Asymmetric synthesis of 1,3-aminoketals

The asymmetric synthesis of α-chiral 1,3-aminoketals 1, useful chiral building blocks for piperidine preparation, was achieved in seven steps involving highly diastereoselective 1,4-addition of Davies’ lithium amide to an α,β-unsaturated ester. Problems of partial racemization observed during transf...

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Bibliographic Details
Published inTetrahedron: asymmetry Vol. 16; no. 22; pp. 3650 - 3660
Main Authors Bariau, Annabelle, Canet, Jean-Louis, Chalard, Pierre, Troin, Yves
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier Ltd 14.11.2005
Elsevier
Subjects
Chemistry
Chemistry, Inorganic & Nuclear
Chemistry, Organic
Chemistry, Physical
Physical Sciences
Science & Technology
BETA-AMINO KETONES
METHOXY-N-METHYLAMIDES
ROUTE
ACID
MANNICH-TYPE REACTION
FORMAL SYNTHESIS
ENANTIOSELECTIVE SYNTHESIS
1ST SYNTHESIS
STEREOSELECTIVE SYNTHESIS
2,4,5-TRISUBSTITUTED PIPERIDINES
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Summary:The asymmetric synthesis of α-chiral 1,3-aminoketals 1, useful chiral building blocks for piperidine preparation, was achieved in seven steps involving highly diastereoselective 1,4-addition of Davies’ lithium amide to an α,β-unsaturated ester. Problems of partial racemization observed during transformation of the ester moiety into a keto function, via a Weinreb amide, were solved using non-conventional experimental conditions. This procedure allowed the preparation of the title compounds in >90% enantiomeric excess.
ISSN:0957-4166
1362-511X
DOI:10.1016/j.tetasy.2005.09.024