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

Abstract

The reaction of [{(ArNCMe)₂CH}Al] (Ar = 2,6-di-iso-propylphenyl) with aryl methyl ethers proceeded with alumination of the sp³ C–O bond. The selectivity of this reaction could be switched by inclusion of a catalyst. In the presence of [Pd(PCy₃)₂], chemoselective sp² C–O bond functionalisation was observed. Kinetic isotope experiments and DFT calculations support a catalytic pathway involving the ligand-assisted oxidative addition of the sp² C–O bond to a Pd–Al intermetallic complex.