[reaction: see text] CuI-exchanged solids based on zeolite materials were investigated for the first time as catalysts in organic synthesis. The catalytic potential of these materials was evaluated in the Huisgen [3 + 2]-cycloaddition. Five CuI-exchanged zeolites were examined and CuI-USY proved to be a novel and efficient heterogeneous ligand-free catalyst for this "click chemistry"-type transformation.

For the first time, copper(I)-exchanged zeolites were developed as catalysts in organic synthesis. These solid materials proved to be versatile and efficient heterogeneous, ligand-free catalytic systems for the Huisgen [3+2] cycloaddition. These cheap and easy-to-prepare catalysts exhibited a wide scope and compatibility with functional groups. They are very simple to use, easy to remove (by filtration), and are recyclable (up to three times without loss of activity). Investigations with deuterated alkynes and deuterated zeolites proved that this Cu(I)-zeolite-catalyzed "click" reaction exhibited a mechanism different from that reported for the Meldal-Sharpless version.

CuI‐modified zeolites, especially CuI–USY, proved to be very efficient catalysts for the homocoupling of terminal alkynes. Such heterogeneous catalysts offer a very simple (no added ligand) and convenient synthesis of diynes, including carbohydrate derivatives. A strong influence of the zeolite pore size has been observed, high (quantitative) yields being obtained with zeolites having large internal cages. The role of zeolite acidic sites in the reaction has been pointed out. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Top Cat! Cu(II)-hydrotalcite (HT) is used as a catalyst for the regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles by [3+2] cycloaddition of various azides and alkynes. The catalyst enjoys advantages such as faster reactivity, good stability, reusability, high catalytic activity without any additives at room temperature, and does not require a nitrogen atmosphere for this "click-chemistry" transformation.

The interaction of alpha,beta-unsaturated carboxylic acids with benzene derivatives was investigated in H-zeolites and led to two distinct but competing processes, cycliacyarylation and decarboxyarylation. Interestingly, H-USY selectively induced the cycliacyarylation cascade reaction, whereas H-ZSM5 selectively promoted the decarboxyarylation cascade.

Triazole derivatives R 0280 Click Chemistry in Cu I -Zeolites: The Huisgen [3 + 2]-Cycloaddition. -Cu(I)-modified zeolites are successfully applied as catalysts in the [3 + 2] cycloaddition of terminal alkynes (I) with azides (II). The reaction proceeds with excellent regioselectivity to afford exclusively 1,4-disubstituted 1,2,3-triazoles (III). -(CHASSAING, S.; KUMARRAJA, M.; SIDO, A. S. S.; PALE, P.; SOMMER*, J.; Org. Lett. 9 (2007) 5, 883-886; Lab. Physicochim. Hydrocarbures, Inst. Chim., Univ. Louis Pasteur, F-67000 Strasbourg, Fr.; Eng.) -Mischke 29-119

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