Cyclodextrins as Artificial Enzyme Supports

Cyclodextrins, described in Chapter 1, are naturally occurring macrocycles that exist in a number of different sizes. Externally they are decorated with hydroxyl groups but have hydrophobic central cavities that can bind appropriately sized guests. In fact they appear to be ideal molecules to use as a basis for an enzyme mimic. Furthermore the hydroxyl groups can be regioselectively functionalized. 

Later work by the Bresow group dispensed with metals entirely. Disubstitution of 3-cyclodextrin with imidazole groups, analogous to the histidine side chains of amino acids in ribonuclease A, led to a catalyst that increases the rate of a small cyclic phosphate by a factor of 120. The selectivity for one product over the other was 99 1 but the rate increase and selectivity were only observed for cyclodextrins 

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