Anion-pi Catalysis Enabled by the Mechanical Bond

We report a series of rotaxane-based anion-it catalysts in which the mechanical bond between a bipyridine macrocycle and an axle containing an NDI unit is intrinsic to the activity observed, including a [3]rotaxane that catalyses an otherwise disfavoured Michael addition in > 60 fold selectivity over a competing decarboxylation pathway that dominates under Bronsted base conditions. The results are rationalized by detailed experimental investigations, electrochemical and computational analysis.