A New Class of Macrocyclic Receptors from iota-Peptides

摘要

Macrocyclic oligomers, such as cyclodextrins, calixarenes, and porphyrins have for decades been among the preeminent receptors and catalysts of bioorganic and medicinal chemistry. These venerable macrocycles form as cyclohomooligomers via cyclooligomer-ization reactions or related processes and do not easily permit the presentation of a series of different substituents in sequence. It would be immensely challenging, if not completely impractical, to prepare a porphyrin with four different substituents in a certain order, a β-cyclodextrin with seven, or a resorc[4]arene with four. For this reason, contemporary applications of these and other important macrocycles must often be suited to symmetrical macrocycles or those bearing only one or two different substituents. This paper presents a new class of macrocycles and demonstrates the potential of these macrocycles to bind guests and display different substituents in sequence. These macrocycles are based on iota-peptides (ι-peptides) and are comparable in size to cyclodextrins, calixarenes, resorcinarenes, and porphyrins.