Evaluation of heterocumulenic ferrocene derivatives for “click” chemistry type reactions

Azidoferrocene (1), 1,1′-diazidoferrocene (2) and 1,1′-diisothiocyanatoferrocene (3) were subjected to reactions from the repertoire of “click” chemistry, with a view to applications in the post-functionalisation of self-assembled monolayers. The copper-catalysed 1,3-dipolar cycloaddition of 1 and FcCtriple bond; length of mdashCH (Fc = ferrocenyl) afforded the expected 1,2,3-triazole derivative under anhydrous and anaerobic conditions. Analogous reactions also succeeded with 2 and RCtriple bond; length of mdashCH (R = Ph, Fc). The Staudinger reaction of 2 with 1,1′-bis(diphenylphosphanyl)ferrocene (dppf) gave the expected bis(iminophosphoranyl)ferrocene in high yield. The nucleophilic addition of 2 equiv. of NHR2 (R = Et, iPr) to 3 afforded the corresponding thiourea derivative in quantitative yield.