Molecular Bowls and Capsules with an Endohedral Functionality: The Stabilization of Highly Reactive Species in Their Inner Phase

Endohedral phases of molecular bowls and capsules have great potential for serving as a reaction environment for the internal functionality as well as a complexing site for the guest molecule. The reactivity of a functional group covalently fixed in the interior of such molecules can be regulated in a unique fashion by the surrounding framework. This article gives an account of the design of novel molecular bowls and capsules bearing an endohedral functionality and the stabilization of highly reactive species by covalent fixation in the interior of such molecules. The target species include a sulfenic acid, a selenenic acid, and a monosubstituted simple enol, which have been recognized as important but elusive intermediates in organic and enzymatic reactions.