Enantioselective Heterogeneous Heck–Matsuda Reaction with Polymer-Supported PyOx Ligands
摘要:
Carboxymethyl C5-functionalized pyridine-oxazoline (PyOx) ligands are immobilized onto Merrifield and Wang resins utilizing three distinct strategies. The immobilized PyOx ligands are employed in the Pd-catalyzed heterogeneous Heck–Matsuda reaction for the desymmetrization of 3-cyclopenten-1-ol, resulting in the production of 20 examples of aryl-penten-1-ols with yields reaching up to 87%, and enantiomeric ratios ranging between 90:10 and 99:1. These outcomes align with those achieved by the homogeneous counterparts, demonstrating comparable efficiency. Subsequent recycling analysis reveals a progressive decline in catalyst efficiency upon reuse, suggesting the formation of palladium black on the catalyst surface.
A Palladium-Catalyzed Enantioselective Addition of Arylboronic Acids to Cyclic Ketimines
作者:Guoqiang Yang、Wanbin Zhang
DOI:10.1002/anie.201302861
日期:2013.7.15
Nicox: A palladium‐catalyzed addition of arylboronicacids to ketimines has been developed to efficiently provide products in up to 99 % yield and 96 % ee. The reactions could be run under aerobic conditions and with unpurified trifluoroethanol (TFE). A pyrrolidine compound bearing a chiral α‐tertiary amine was synthesized in several steps without loss of enantioselectivity. TFA=trifluoroacetate.