Methylene C(sp3)-H Β,β'-Diarylation of Cyclohexanecarbaldehydes Promoted by a Transient Directing Group and Pyridone Ligand.

A hindered β-amino amide transient directing group effects di-trans-arylation of cyclohexanecarbaldehydes. The amide N-substituents are shown to affect yield and can enhance the rate of arylation compared with the α-amino acid. Addition of a pyridone ligand further enhanced reactivity. The reaction is successful for a range of aryl iodides, and various substituted cyclohexane carboxaldehydes, providing functionalized products from simple feedstocks. A mechanism is proposed evoking a transient enamine.