Pd-Catalyzed Cross-Coupling Mediated by Polymer-Supported Siloxanes
Design, Synthesis, and Application of Polymer-Supported Silicon-Transfer Agents for Cross-Coupling Reactions with Organolithium Reagents.
J. Org. Chem. 2017;
15 December 2017 (online)
Polymer-supported siloxanes were developed as transfer agents for cross-coupling reactions involving organolithium reagents. For example, the polystyrene-supported siloxane 1 was treated with an aryl or alkenyl lithium 2, and the resulting material was treated with an aryl halide 3 in the presence of PdCl2, CuI, and ligand L to give the corresponding product 4 in 68–97% yield.
The transfer agent 1 was recovered almost quantitatively by simple filtration and rinsing, and reused in the cross-coupling several times. No cross-contamination of the products 4 was detected in a series of ten reactions with recycled 1 and various combinations of organolithium reagents 2 and aryl halides 3.