Organocatalytic Ring-Opening Reactions in a Molecular Vessel

Significance

The highly regioselective ring opening of epoxides, like 1, yielding exo product 2a, assisted by the vase-like resorcinarene scaffold receptor 3 is reported. Species 3 contains a catalytically active carboxylic acid functionality on its concave inner surface. Complementary, the reaction was conducted in the presence of non-cavitative model acid catalyst 4. The significantly faster reaction using 3, shows that its sophisticated architecture, with hydrogen-bonding and π-stacking domains in the scaffold is beneficial for the regio­selective transformation of host substrate 1. These diverse interaction modes were also interpreted to be responsible for the comparatively higher product selectivity, in favor of 5-exo product 2a.