A modular synthesis of 1,4,5-trisubstituted 1,2,3-triazoles with ferrocene moieties

Abstract

Regioselective synthesis of 1,2,3-triazoles with ferrocenyl moieties in positions 1, 4, and 5 was carried out in a two-step reaction sequence: a copper-mediated azide–alkyne cycloaddition followed by a palladium-catalyzed cross-coupling. A new route towards 5-iodo-1,2,3-triazoles was developed using N-iodomorpholine hydrogen iodide, instead of the corrosive and toxic ICl, as the I+ source. The novel methodology together with a consecutive Suzuki or Sonogashira reaction was shown to be a useful procedure for the synthesis of a wide range of ferrocenyl 1,2,3-triazoles with di- and triferrocenyl derivatives among them.