Kapeller Dagmar C, Brecker Lothar, Hammerschmidt Friedrich
University of Vienna, Institute of Organic Chemistry, Währingerstr. 38, 1090 Vienna, Austria.
Chemistry. 2007;13(34):9582-8. doi: 10.1002/chem.200701054.
Several homochiral oxymethyllithiums, chiral by virtue of the hydrogen isotopes protium and deuterium, were prepared. They were tested for their microscopic configurational stability in intramolecular isomerizations, such as the silyl- and germyl-[1,2]-retro-Brook and the sigmatropic[2,3]-Wittig rearrangement. The influence of temperature, solvent, and migrating group on the stability of the intermediate carbanions was studied. Furthermore, the stereochemical course of these rearrangements was elucidated, resulting in highly enantioenriched alcohols (90-97% ee; ee=enantiomeric excess) up to temperatures of 0 degrees C.
制备了几种因氢同位素（氕和氘）而具有手性的同手性氧甲基锂。对它们在分子内异构化反应中的微观构型稳定性进行了测试，如硅基和锗基的[1,2]-逆布鲁克重排以及[2,3]-西格玛重排维蒂希重排。研究了温度、溶剂和迁移基团对中间体碳负离子稳定性的影响。此外，阐明了这些重排反应的立体化学过程，在高达0摄氏度的温度下可得到对映体过量高达90 - 97%（ee = 对映体过量）的高度对映体富集的醇。
