Görbe Tamás, Lihammar Richard, Bäckvall Jan-E
Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91, Stockholm, Sweden.
Chemistry. 2018 Jan 2;24(1):77-80. doi: 10.1002/chem.201704691. Epub 2017 Nov 30.
Tertiary alcohols are important structural motifs in natural products and building blocks in organic synthesis but only few methods are known for their enantioselective preparation. Chiral resolution is one of these approaches that leaves one enantiomer (50 % of the material) unaffected. An attractive method to increase the efficiency of those resolutions is to racemize the unaffected enantiomer. In the present work, we have developed a practical racemization protocol for tertiary alcohols. Five different acidic resin materials were tested. The Dowex 50WX8 was the resin of choice since it was capable of racemizing tertiary alcohols without any byproduct formation. Suitable solvents and a biphasic system were investigated, and the optimized system was capable of racemizing differently substituted tertiary alcohols.
叔醇是天然产物中的重要结构单元和有机合成中的砌块，但目前已知的对映选择性制备方法却很少。手性拆分是其中一种方法，该方法不会影响其中一种对映体（占原料的50%）。提高这些拆分效率的一种有吸引力的方法是使未受影响的对映体发生外消旋化。在本工作中，我们开发了一种实用的叔醇外消旋化方案。测试了五种不同的酸性树脂材料。Dowex 50WX8是首选树脂，因为它能够使叔醇发生外消旋化而不产生任何副产物。研究了合适的溶剂和双相体系，优化后的体系能够使不同取代的叔醇发生外消旋化。
