Initially, we aimed to establish whether copper mediated C-H functionalization reactions were feasible with a catalytic TDG. Common bidentate groups that may function as transient directing groups also chelate copper, and indeed find application as ligands in copper mediated reactions. Studies focused on C-H sulfonylation of benzaldehyde and o-tolualdehyde by assessing the potential of different classes of amines as TDGs. Copper (II) acetate was selected for early studies to effect both a putative concerted metalation deprotonation (CMD) process and subsequent functionalization steps, as well as to provide an inexpensive and non-toxic stoichiometric oxidant. Potassium carbonate base and HFIP, used previously in Pd-mediated transient processes, were employed to screen for successful ortho-sulfonylation using 25 mol% of the transient directing groups (Scheme 2).