✦ LIBER ✦
Amphiphilic Carbohydrate-Based Mesogens, VIII. A Facile Synthetic Route to Mesogenic L-ribo-1,2,3,4-alkanetetrols
✍ Scribed by Dahlhoff, Wilhelm V.
- Book ID
- 102368505
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 489 KB
- Volume
- 1992
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Abstract
The Wittig olefinations of 2,3‐O‐isopropylidene‐D‐ribofuranose (1) with two equivalents of alkylidenetriphenylphosphorane (alkylidene: hexylidene — undecylidene) followed by hydrogenation catalyzed by palladium on carbon and subsequent deprotection yield (2__R__,3__S__,4__S__‐(“L‐”ribo)‐1,2,3,4‐alkanetetrols 5. These amphiphiles form the smectic A mesophase on melting. However, when 1 is heated with one equivalent of the alkylidenetriphenylphosphoranes for longer periods, (2__R__,3__S__,4__R__)‐(“D‐lyxo”)‐1,2,3,4‐alkanetetrol‐type products 4 predominate.