Novel approach to the stereoselective synthesis of polyprenols via directed aldol condensation. Preparation of heptaprenols ωtttcctOH.
✍ Scribed by N.Ya. Grigorieva; I.M. Avrutov; A.V. Semenovsky
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- French
- Weight
- 250 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
New convenient and stereoselective route to linear isoprenoids including the construction of Z-trisubstituted double bond is elaborated based on directed aldol condensation.
We have previously reported' that the directed aldol condensation2 of dlitbated aldimines J_ with aldehydes 1 is highly stereoselective, even when R and B" are longchain alkyles, stituted acroleins A3*4 due to the thermodynaeric preference of E-disub-
Keeping in mind well documented5 reductive transformation of aldehydes 2 into hydrocarbons 2 we 6UppO8ed that suitably chosen components of the sequence 1+~-~--3 will permit to elaborate new, convenient and stereoselective route to linear isoprenoids containing Z-trisubstituted double bonds. Here we reported the adaptation of this approach for the synthesis of polyprenols I", the membrane soluble carbohydrate carriers essential for the biosynthesis of bacterial polysaccharidee as well as of proand eucariotic glycoproteins. This communication deals with the synthesis of heptaprenol&ttcccOH s, its A2 -isomer (2) end protected aldehyde 5 which csn be used as a substrate for the synthesis of higher polyprenols according to this approach.