Synthesis of decalin synthons of bioactive terpenoids: Lewis acid catalyzed Diels-Alder reactions
โ Scribed by T. Mayelvaganan; Shreeshailkumar B. Hadimani; Sujata V. Bhat
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- French
- Weight
- 189 KB
- Volume
- 53
- Category
- Article
- ISSN
- 0040-4020
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โฆ Synopsis
Diels-Alder reaction of 1,3,3-trimethyl-2-vinylcyclohexene I with conjugated ketones 2 -7 in the presence of Lewis acid leads to regto-and stereo-selective formation of bicyclic adducts 8 -13 versatile intermediates to labdanes, abietane and spongian diterpenoids.
๐ SIMILAR VOLUMES
The effect of Lewis acid catalysts on the mechanism of Diels-Alder reactions is studied using the MINDO/3 method. It is found that they tend to increase the two-step character of the process through a more important participation of the charge-transfer configuration.
6-Vinylpurines readily undergo Diels-Alder reactions with dienes. Both reactivity and endo selectivity are greatly improved when the cycloadditions are performed in the presence of zinc chloride. Lewis acid mediated Diels-Alder reaction of 6-vinylpurine riboside was employed as a key step in the syn