“Click Chemistry” in Zeolites: Copper(I) Zeolites as New Heterogeneous and Ligand‐Free Catalysts for the Huisgen [3+2] Cycloaddition

Abstract

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.

Metal-doped Zeolites as Green Catalysts for Organic Synthesis

“…As expected, the catalyst can be easily recovered through filtration and recycled four times without any significant change in yield and conversion [21]. Copper(I) leaching could have been an issue, and this has thus been investigated, revealing that leaching did not account for more than 5 % of the transformation.…”

“…High yields of triazoles were routinely obtained with a wide variety of starting materials. The reaction scope indeed proved as large as the one of the Sharpless-Meldal version [21]. However, the mechanism seems to be different (Scheme 3).…”

“…However, the mechanism seems to be different (Scheme 3). Investigations with deuterated substrates and zeolites suggested that no acetylide is formed within the Cu I zeolites while it has been shown that such intermediates are produced in the Sharpless-Meldal version [21].…”

Metal-catalyzed azide-alkyne “click” reactions: Mechanistic overview and recent trends

“…17a) To explore the NiAAC reaction pathway, deuteration experiments were conducted (Fig. 17b) in the presence of Ni(0) indicating that, unlike the copper-acetylide formation in CuAAC, the cycloaddition went through a metallocycle [107]. Thus in their proposed mechanism, the reaction starts on the Raney nickel surface by acetylene complexation leading to the π-complex 11 (Fig.…”

Facile and efficient sonochemical synthesis of 1,4-disubstituted 1,2,3-triazole derivatives catalyzed by CuI under mild conditions

“…Melting points of all the known compounds were compared with melting points obtained by literature survey. Also, the structures of products were confirmed by comparison of IR, 1 H NMR, and 13 C NMR data with those from authentic samples prepared by use of literature methods [23,24]. …”