Rideau Emeline, Fletcher Stephen P
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK.
Beilstein J Org Chem. 2015 Dec 3;11:2435-43. doi: 10.3762/bjoc.11.264. eCollection 2015.
Asymmetric allylic alkylation is a powerful reaction that allows the enantioselective formation of C-C bonds. Here we describe the asymmetric alkylation of alkylzirconium species to racemic 3,6-dihydro-2H-pyrans. Two systems were examined: 3-chloro-3,6-dihydro-2H-pyran using linear optimization (45-93% ee, up to 33% yield, 5 examples) and 3,6-dihydro-2H-pyran-3-yl diethyl phosphate with the assistance of a design of experiments statistical approach (83% ee, 12% yield). (1)H NMR spectroscopy was used to gain insight into the reaction mechanisms.
不对称烯丙基烷基化是一种强大的反应，可实现对映选择性地形成碳-碳键。在此，我们描述了烷基锆物种与外消旋3,6-二氢-2H-吡喃的不对称烷基化反应。研究了两个体系：使用线性优化方法的3-氯-3,6-二氢-2H-吡喃（对映体过量百分数为45%-93%，产率高达33%，5个实例）和借助实验设计统计方法的3,6-二氢-2H-吡喃-3-基二乙基磷酸酯（对映体过量百分数为83%，产率为12%）。利用核磁共振氢谱来深入了解反应机理。
