Configurational Stability of Oxymethyllithiums as Intermediates in Intramolecular Rearrangements
作者:Dagmar C. Kapeller、Lothar Brecker、Friedrich Hammerschmidt
DOI:10.1002/chem.200701054
日期:2007.11.26
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
通过氢同位素氕和氘,制备了几种手性纯手性氧甲基锂。测试了它们在分子内异构化中的微观构型稳定性,例如甲硅烷基和锗基-[1,2]-retro-Brook 和 sigmatropic[2,3]-Wittig 重排。研究了温度、溶剂和迁移基团对中间碳负离子稳定性的影响。此外,阐明了这些重排的立体化学过程,导致高度对映体富集的醇(90-97% ee;ee = 对映体过量),最高温度可达 0 摄氏度。