A saturated Pd-N-heterocyclic complex was immobilized on an amorphous silica. The complex itself is of very high thermal stability. However, TEM observations, hot filtration, reusability, and poisoning tests all revealed that the complex acted only as a precatalyst to highly active Pd species in Mizoroki-Heck reactions when immobilized. The complex appears more stable when used under homogeneous reaction conditions. The immobilized complex afforded high turnover numbers, 10 4 -10 5 . The higher turnover frequencies were realized at the lower Pd concentrations, which is a characteristic property of ligand-free Pd catalyzed reactions.

Nine a-hydroxyallenes 1/3 were cyclized to the corresponding 2,5-dihydrofurans 2/4 with complete axis-to-center chirality transfer in the presence of 1 mol% of AuBr 3 using [BMIM] A C H T U N G T R E N N U N G [PF 6 ] as solvent at room temperature. The gold catalyst/ionic liquid system is air-stable and recyclable. The leaching of the gold catalyst upon extraction of the product is extremely low (0.03% after five runs).

The Pd(NH 3 ) 4 2+ -loaded NaY zeolite was found to be a highly active catalyst precursor for Suzuki-Miyaura (SM) reactions of aryl bromides and aryl chlorides at low Pd concentrations in air. Aryl bromides and arylboronic acids can couple effectively both in pure water and in N,Ndimethylacetamide/water mixtures (1/1) within minutes with turnover frequencies (TOF) up to 4 × 10 5 h −1 . The presence of a minute amount of water was crucial for the success of the reaction with chloroarenes. The excess amounts of as-received zeolite provided the necessary water for the reaction. The results suggest that the combined use of the water-zeolite system may have a synergistic effect in the reaction.

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