ChemInform Abstract: Dispiroketals in Synthesis. Part 24. Preparation and Use of Chiral 2,2′-Bis(triisopropylsilyloxymethyl)bi(dihydropyran)s as New Protecting and Resolving Agents for 1,2-Diols.
✍ Scribed by Dramane Laine; Morifumi Fujita; Steven V. Ley
- Publisher
- John Wiley and Sons
- Year
- 2010
- Weight
- 36 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0931-7597
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✦ Synopsis
Dispiroketals in Synthesis. Part 24. Preparation and Use of Chiral 2,2'-Bis(triisopropylsilyloxymethyl)bi(dihydropyran)s as New Protecting and Resolving Agents for 1,2-Diols.
-Reaction of the title bis(dihydropyran) (VI), prepared starting from glycidol derivative (I) in an improved and shortened route, with rac-diols (VII) and (XI) in the presence of CSA provides the corresponding dispiroketals (VIII) and (XII), resp., in a highly diastereoselective manner. A three-step deketalization procedure is developed to release optically pure diacetates (X) and (XIII), resp., in high yields. The corresponding stereoisomeric diacetates can be obtained in comparable yields and selectivity using bis(dihydropyran) (ent-VI) as chiral auxiliary.