ChemInform Abstract: D-Mannitol as the Chiral Source for the EPC Synthesis of Both Enantiomers of 3-Ethoxycarbonyl-4-hydroxy-2-isoxazolines and Highly Functionalized Tricyclic Systems.
✍ Scribed by Emanuela Marotta; Marco Baravelli; Luigi Maini; Paolo Righi; Goffredo Rosini
- Publisher
- John Wiley and Sons
- Year
- 2010
- Weight
- 35 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0931-7597
No coin nor oath required. For personal study only.
✦ Synopsis
1999 isoxazole derivatives isoxazole derivatives R 0240 15 -150 D-Mannitol as the Chiral Source for the EPC Synthesis of Both Enantiomers of 3-Ethoxycarbonyl-4-hydroxy-2-isoxazolines and Highly Functionalized Tricyclic Systems.
-Isoxazoline oxides (V) and (XII) are obtained as diastereomeric mixtures from mannitol derivative (II) by a tandem nitroaldol-cyclization reaction of nitroacetate (III) with an in situ generated aldehyde. Because any attempts to separate the isomers are unsuccessful, the different rates of silylation of the cis-and trans-hydroxyl groups are used for the chromatographic separation of unreacted cis-isomer (V) and protected cis-and trans-compounds (VI) and (VII). The enantiomerically pure target endo-and exo-tricycles (IX) and (XIII) are formed exclusively from the cis-and trans-precursors, respectively. Deoxygenation and deprotection of protected oxides (VI) and (VII) gives access to isoxalines such as (XI) without epimerization and/or decomposition. -(MAROTTA, EMANUELA; BAR-