Ligand Bite Angle-Dependent Palladium-Catalyzed Cyclization of Propargylic Carbonates to 2-Alkynyl Azacycles or Cyclic Dienamides
作者:David S. B. Daniels、Alison S. Jones、Amber L. Thompson、Robert S. Paton、Edward A. Anderson
DOI:10.1002/anie.201309162
日期:2014.2.10
palladium‐catalyzed cyclization of propargylic carbonates with sulfonamide nucleophiles is critically dependent on the bite angle of the bidentate phosphine ligand. Ligands with small bite angles favor attack on the central carbon atom of an allenylpalladium intermediate to afford cyclic dienamide products, whereas the use of those with large bite angles leads to alkynyl azacycles, with high stereoselectivity
磺酰胺亲核试剂对丙炔碳酸酯的钯催化环化的区域选择性至关重要地取决于二齿膦配体的咬合角。具有小咬合角的配体有利于攻击烯丙基钯中间体的中心碳原子以提供环状二烯酰胺产物,而使用具有大咬合角的那些会导致炔基氮杂环,具有高的立体选择性。还介绍了反应途径的计算分析。