Intramolecular reactions of compounds derived from sugars. Part III. High diastereoselection in the intramolecular diels-alder reaction of sugar based 1,7(E,Z),9-decatrienes
✍ Scribed by Pál Herczegh; Zsély Martina; Szilágyi László; Dinya Zoltán; Bognár Rezső
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- French
- Weight
- 431 KB
- Volume
- 45
- Category
- Article
- ISSN
- 0040-4020
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✦ Synopsis
Abstract4 A mixture of tetrachiral deca-1,7E,9-triene 2 and its 72 isomer 2 was prepared from D-glucose by the use of two Wittig olefination reactions. When 5 or 6 were subjected to intramolecular Diels-Alder reaction un'-er Thermal conditions the same, cis-fused octahydronaphtalene enantiomer 9 was formed exclusively. This phenomenon can be explained bv Z+E isomerization of 6 to 5. Sim&larly, when a mixture-of trier&es 7 and 8 was heated ?i:t -160 the formation of a sinale Droduct TO was-observed. Stereochemical outcome of the reactions can brrationalized by inspection of the possible conformers leading to transition states.
A great number of papers have been published in the past decade dealing with the use of intramolecular Diels-Alder reactions for the syn+ thesis of complex natural products 2,3 . Numerous efforts have been made to elaborate very highly stereocontrolled versions of this reaction 4-10 .
Recently we have observed exceptionally good diastereoselection in