Intramolecular palladium(ii)/(iv) catalysed C(sp 3 )-H arylation of tertiary aldehydes using a transient imine directing group.

Palladium catalysed beta-C(sp(3))-H activation of tertiary aldehydes using a transient imine directing group enables intramolecular arylation to form substituted indane-aldehydes. A simple amine bearing a methyl ether (2-methoxyethan-1-amine) is the optimal TDG to promote C-H activation and reaction with an unactivated proximal C-Br bond. Substituent effects are studied in the preparation of various derivatives. Preliminary mechanistic studies identify a reversible C-H activation, product inhibition and suggest that oxidative addition is the turnover limiting step.