High-Performance Group Transfer Catalysis by Copper Complex with Redox-Active Ligand in an Entatic State

Metalloenzymes use earth-­abundant non-­noble metals to perform
high‐fidelity transformations in the biological world. To ensure chemical efficiency, metalloenzymes have acquired evolutionary reactivity­‐enhancing tools. Among these, the entatic state model states that a strong steric entatic state, strongly improving the reactivity. However, while the original definition refers both to the transfer of electrons or chemical groups, the chemical application of this concept in synthetic systems has mostly focused on electron transfer, therefore eluding chemical transformations. Here we report that a highly‐strained redox-­active ligand enables a cooper complex to perform catalytic nitrogen-­ and carbon-­‐group transfer in as fast as two minutes, thus exhibiting a strong increase in reactivity compared to its unstrained analogue. This is the first report combining two reactivity-­‐enhancing features from metalloenzymes, entasis and redox cofactors, applied to group-­transfer catalysis.