Window[1]resorcin[3]arenes: A Novel Macrocycle Able to Self-Assemble to a Catalytically Active Hexameric Cage

The hexameric resorcin[4]arene capsule has been utilized
as one
of the most versatile supramolecular capsule catalysts. Enlarging
its size would enable expansion of the substrate size scope. However,
no larger catalytically active versions have been reported. Herein,
we introduce a novel class of macrocycles, named window[1]resorcin[3]arene
(wRS), that assemble to a cage-like hexameric host. The new host was
studied by NMR, encapsulation experiments, and molecular dynamics
simulations. The cage is able to bind tetraalkylammonium ions that
are too large for encapsulation inside the hexameric resorcin[4]arene
capsule. Most importantly, it retained its catalytic activity, and
the accelerated conversion of a large substrate that does not fit
the closed hexameric resorcin[4]arene capsule was observed. Thus,
it will help to expand the limited substrate size scope of the closed
hexameric resorcin[4]arene capsule.