Harnessing supramolecular confinement for the semihydrogenation of aromatic alkynes

The immobilization of 1-methyl-1,4-diazabicyclo[2.2.2]octane-1-ium iodide in a supramolecular capsule formed from 2,8,14,20-tetra-undecyl-resorcin[4]arene and water in the presence of hydrochloric acid enabled the reaction of silane with arylacetylenes. This organocatalyzed reaction predominantly yielded the corresponding semihydrogenated products. The presence of the three components, ammonium, HCl, and capsule, was necessary to obtain significant catalytic activity at 60 °C. This easily accessible catalytic system was tested on nine arylacetylenes following the optimization of the operating conditions.