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Synthesis of 2S,5S- and 2R,5S-5-Hydroxypipecolic Acid via Amide-Methylenation of S-5-Hydroxy-2-piperidone with Dimethyltitanocene

Please always quote using this URN: urn:nbn:de:bvb:20-opus-38288
  • A route to 2S,5S-and 2R,5S-hydroxypipecolic acid is presented, starting with the enantiopure 5S-5-hydroxy-piperidone 7. The key step of this reaction sequence is the chemoselsctive methylenation of the amide carbonyl group of 8 with dimethyltitanocene 9 to 10. The transformation of the exocyclic enecarbamate double bond to the carboxylic acid group is best accomplished via hydroboration/oxidation to the alcohol 11a,b. Separation and oxidation of the dlastereomers 11a,b, to 148. and 14b, and hydrolysis furnishes the diastereomeric pipecolicA route to 2S,5S-and 2R,5S-hydroxypipecolic acid is presented, starting with the enantiopure 5S-5-hydroxy-piperidone 7. The key step of this reaction sequence is the chemoselsctive methylenation of the amide carbonyl group of 8 with dimethyltitanocene 9 to 10. The transformation of the exocyclic enecarbamate double bond to the carboxylic acid group is best accomplished via hydroboration/oxidation to the alcohol 11a,b. Separation and oxidation of the dlastereomers 11a,b, to 148. and 14b, and hydrolysis furnishes the diastereomeric pipecolic acids 15a and 15b in enantiopure form.show moreshow less

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Metadaten
Author: Eberhard Heller, Claus Herdeis
URN:urn:nbn:de:bvb:20-opus-38288
Document Type:Journal article
Faculties:Fakultät für Chemie und Pharmazie / Institut für Pharmazie und Lebensmittelchemie
Language:English
Year of Completion:1993
Source:In : Tetrahedron: Asymmetry (1993) 4, 9, 2085-2094.
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
GND Keyword:Chemie; Asymmetrie
Release Date:2009/10/02