Pd-Catalyzed Cross-Coupling Mediated by Polymer-Supported Siloxanes

Key words

silicon - organolithium reagents - palladium catalysis - cross-coupling - transfer agents

Significance

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.

 

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Comment

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.

 

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