Alumination of aryl methyl ethers: switching between sp2 and sp3 C-O bond functionalisation with Pd-catalysis

The reaction of [{(ArNCMe)(2)CH}Al] (Ar = 2,6-di-iso-propylphenyl) with aryl methyl ethers proceeded with alumination of the sp(3) C-O bond. The selectivity of this reaction could be switched by inclusion of a catalyst. In the presence of [Pd(PCy3)(2)], chemoselective sp(2) C-O bond functionalisation was observed. Kinetic isotope experiments and DFT calculations support a catalytic pathway involving the ligand-assisted oxidative addition of the sp(2) C-O bond to a Pd-Al intermetallic complex.

Automated summary

A new method for controlling the selectivity of aryl methyl ether reactions was discovered in this study, by using the catalyst [Pd(PCy3)(2)] to achieve chemoselective functionalisation of the sp(2) C-O bond. Experimental evidence supports a catalytic pathway involving ligand-assisted oxidative addition of the sp(2) C-O bond to a Pd-Al intermetallic complex.