Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84112, USA.
J Am Chem Soc. 2010 Dec 15;132(49):17471-82. doi: 10.1021/ja108106h. Epub 2010 Nov 17.
The mechanism of an enantioselective palladium-catalyzed alkene difunctionalization reaction has been investigated. Kinetic analysis provides evidence of turnover-limiting attack of a proposed quinone methide intermediate with MeOH and suggests that copper is involved in productive product formation, not just catalyst turnover. Through examination of substrate electronic effects, a Jaffé relationship was observed correlating rate to electronic perturbation at two positions of the substrate. Ligand effects were evaluated to provide evidence of rapid ligand exchange between palladium and copper as well as a correlation between ligand electronic nature and enantioselectivity.
本研究考察了手性钯催化烯烃双官能化反应的机理。动力学分析为提出的醌甲醚中间体与甲醇的限速进攻提供了证据，并表明铜不仅参与了催化剂的循环，还参与了产物的生成。通过考察底物的电子效应，观察到了与底物两个位置的电子扰动相关的 Jaffé 关系，该关系与反应速率相关联。配体效应的评估为钯和铜之间快速配体交换以及配体电子性质与对映选择性之间的相关性提供了证据。
