Site-Selective Heterofunctionalization of Cyclodextrins: Discovery, Development, and Use in Catalysis

Abstract

To fulfill the promise offered by concave molecules such as cyclodextrins, there is a desperate need for efficient methods for multiple heterofunctionalization. We have developed several strategies for preparing heterofunctionalized cyclodextrins based on a newly discovered regioselective debenzylation reaction of sugars and an understanding of its mechanism. Bascule bridging and tandem azide reduction–deprotection are two complementary ways of attaining an unprecedented degree of complexity of functionalization of the primary rim of cyclodextrins, permitting access to a diverse library of functionalized cyclodextrins. The resulting complex structures have a number of applications in a wide range of areas. We have explored some of these, such as asymmetric catalysis using regioisomers to induce enantioselectivity or very high turnover numbers, but it is our firm belief that this methodology opens many other possibilities.