A highly diastereoselective addition of lithiated methoxyallene 3 to chiral cyclic nitrones 1 and 2 provided N-hydroxy pyrrolidines 4 and 5, respectively, which cyclized to bicyclic 1,2-oxazines 6 and 7 by simple stirring in dilute CH2Cl2 solution. Storage of 4 in a more concentrated solution led to formation of a 60:40 mixture of 1,2-oxazine 6 and amine oxA highly diastereoselective addition of lithiated methoxyallene 3 to chiral cyclic nitrones 1 and 2 provided N-hydroxy pyrrolidines 4 and 5, respectively, which cyclized to bicyclic 1,2-oxazines 6 and 7 by simple stirring in dilute CH2Cl2 solution. Storage of 4 in a more concentrated solution led to formation of a 60:40 mixture of 1,2-oxazine 6 and amine oxide 8. Hydroboration of 7 furnished the hydroxy-substituted bicyclic 1,2-oxazine 9 with excellent diastereoselectivity. Hydrogenolysis of 6 provided the substituted pyrrolidine derivative 10.
Synthesis of New Enantiopure Bicyclic 1,2-Oxazines by Addition of Lithiated Methoxyallene to Chiral Cyclic Nitrones / R. Pulz; S. Cicchi; A. Brandi; H.-U. Reissig. - In: EUROPEAN JOURNAL OF ORGANIC CHEMISTRY. - ISSN 1434-193X. - STAMPA. - 2003:(2003), pp. 1153-1156.
Synthesis of New Enantiopure Bicyclic 1,2-Oxazines by Addition of Lithiated Methoxyallene to Chiral Cyclic Nitrones
CICCHI, STEFANO;BRANDI, ALBERTO;
2003
Abstract
A highly diastereoselective addition of lithiated methoxyallene 3 to chiral cyclic nitrones 1 and 2 provided N-hydroxy pyrrolidines 4 and 5, respectively, which cyclized to bicyclic 1,2-oxazines 6 and 7 by simple stirring in dilute CH2Cl2 solution. Storage of 4 in a more concentrated solution led to formation of a 60:40 mixture of 1,2-oxazine 6 and amine oxA highly diastereoselective addition of lithiated methoxyallene 3 to chiral cyclic nitrones 1 and 2 provided N-hydroxy pyrrolidines 4 and 5, respectively, which cyclized to bicyclic 1,2-oxazines 6 and 7 by simple stirring in dilute CH2Cl2 solution. Storage of 4 in a more concentrated solution led to formation of a 60:40 mixture of 1,2-oxazine 6 and amine oxide 8. Hydroboration of 7 furnished the hydroxy-substituted bicyclic 1,2-oxazine 9 with excellent diastereoselectivity. Hydrogenolysis of 6 provided the substituted pyrrolidine derivative 10.File | Dimensione | Formato | |
---|---|---|---|
2003_EJOC_1153.pdf
Accesso chiuso
Tipologia:
Versione finale referata (Postprint, Accepted manuscript)
Licenza:
Tutti i diritti riservati
Dimensione
101.27 kB
Formato
Adobe PDF
|
101.27 kB | Adobe PDF | Richiedi una copia |
I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.