The N-alkylation of sulfonamides with alcohols in water catalyzed by a water-soluble metal–ligand bifunctional iridium complex [Cp*Ir(biimH2)(H2O)][OTf]2?

New Journal of Chemistry Pub Date: 2019-06-10 DOI: 10.1039/C9NJ02542A

Abstract

The iridium complex [Cp*Ir(biimH2)(H2O)][OTf]2 (Cp* = η5-pentamethylcyclopentadienyl, biimH2 = 2,2′-biimidazole) was synthesized and developed as a new-type of water-soluble metal–ligand bifunctional catalyst for the N-alkylation of poorly nucleophilic sulfonamides with alcohols in water. In the presence of catalyst (1 mol%) and Cs2CO3 (0.1 equiv.), a series of desirable products was obtained in 74–91% yields under microwave irradiation. Mechanistic experiments revealed that the presence of NH units in the imidazole ligand is crucially important for the catalytic activity of the iridium complex. Notably, this research would facilitate the process of water-soluble metal–ligand bifunctional catalysis for the hydrogen autotransfer process.

Graphical abstract: The N-alkylation of sulfonamides with alcohols in water catalyzed by a water-soluble metal–ligand bifunctional iridium complex [Cp*Ir(biimH2)(H2O)][OTf]2
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