Cationic organotin cluster [t‐Bu2Sn(OH)(H2O)]22+2OTf−‐catalyzed one‐pot three‐component syntheses of 5‐substituted 1H‐tetrazoles and 2,4,6‐triarylpyridines in water

The cationic organotin cluster [t-Bu2Sn(OH)(H2O)](2)(2+)2OTf(-) is easy to prepare and stable in air. The catalytic activity of [t-Bu2Sn(OH)(H2O)](2)(2+)2OTf(-) as a neutral organotin Lewis acid catalyst is probed through the one-pot three-component syntheses of 5-substituted 1H-tetrazoles from aldehydes, hydroxylamine hydrochloride and sodium azide, and of 2,4,6-triarylpyridines from aromatic aldehydes, substituted acetophenones and ammonium acetate. The reactions proceed well in the presence of 1 mol% of [t-Bu2Sn(OH)(H2O)](2)(2+)2OTf(-) in water and provide the corresponding 5-substituted 1H-tetrazoles and 2,4,6-triarylpyridines in good to excellent yields. The method reported has several advantages such as the catalyst being neutral, low catalyst loading and use of water as a green solvent.