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

Abstract

The cationic organotin cluster [t‐Bu2Sn(OH)(H2O)]22+2OTf− is easy to prepare and stable in air. The catalytic activity of [t‐Bu2Sn(OH)(H2O)]22+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)]22+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.