PMPBO
If you have any other questions, please contact our experts.
PMPBO was identified as a potent ligand to promote copper-catalyzed coupling between aryl bromides/iodides and phenols for the synthesis of diaryl ethers under mild reaction conditions using low catalyst loadings (down to 0.2-2 mol %). To test its performance, PMPBO was first applied to the model cross-coupling of 4-methylbromobenzene with phenol in the presence of CuI as catalyst (88% yield with 0.5 mol % catalyst and ligand loading). The results are comparable to or exceed many previously reported ligands including diketones, amino acids, and 8-hydroxyquinoline in promoting this transformation, showcasing the high promoting effect of PMPBO. The ability of PMPBO and related oxalamide ligands to work under much lower catalyst loadings than previously reported systems (5-20 mol %) is a significant improvement.
The low catalytic requirements, broad substrate scope, and operational simplicity of this system also make it a viable and scalable solution for industrial applications including the synthesis of biologically active molecules and materials with diaryl-ether linkages.
Fig. 1 PMPBO for copper-catalyzed cross-coupling reaction. (Zhai Y.; et al. 2017)
References
- Zhai Y, et al. Copper-catalyzed diaryl ether formation from (hetero) aryl halides at low catalytic loadings. The Journal of Organic Chemistry, 2017, 82(9): 4964-4969.
