Carbanion-Accelerated Claisen Rearrangements: Asymmetric Induction with Chiral Phosphorus-Stabilized Anions
作者:Scott E. Denmark、John E. Marlin、G. Rajendra
DOI:10.1021/jo301919e
日期:2013.1.4
at room temperature in high yield, and the rearrangements are highly site- and stereoselective. The first examples of asymmetric induction in the Claisen rearrangement with chiral, phosphorus, anion-stabilizing groups are described. The observed asymmetric induction is highly dependent on the structure of the auxiliary and the metal counterion involved. Both internal and relative diastereoselectivity
碳负离子加速的克莱森重排已扩展到包括磷碳负离子稳定基团。适当取代的烯丙基乙烯基醚是通过烯丙基氧化物与磷取代的丙二烯的亲核加成来合成的,磷取代的丙二烯由简单的原料一步获得。磷稳定、碳负离子加速的克莱森重排在室温下以高产率快速进行,并且重排具有高度的位点和立体选择性。描述了手性、磷、阴离子稳定基团在克莱森重排中不对称诱导的第一个例子。观察到的不对称感应高度依赖于助剂的结构和所涉及的金属反离子。内部和相对非对映选择性都很高。