Synthesis of 2S,5S- and 2R,5S-5-Hydroxypipecolic Acid via Amide-Methylenation of S-5-Hydroxy-2-piperidone with Dimethyltitanocene
Zitieren Sie bitte immer diese 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.…
Autor(en): | Eberhard Heller, Claus Herdeis |
---|---|
URN: | urn:nbn:de:bvb:20-opus-38288 |
Dokumentart: | Artikel / Aufsatz in einer Zeitschrift |
Institute der Universität: | Fakultät für Chemie und Pharmazie / Institut für Pharmazie und Lebensmittelchemie |
Sprache der Veröffentlichung: | Englisch |
Erscheinungsjahr: | 1993 |
Originalveröffentlichung / Quelle: | In : Tetrahedron: Asymmetry (1993) 4, 9, 2085-2094. |
Allgemeine fachliche Zuordnung (DDC-Klassifikation): | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
Normierte Schlagworte (GND): | Chemie; Asymmetrie |
Datum der Freischaltung: | 02.10.2009 |