N-Metallocenyl Ynamides: Preparation, Oxidative Functionaliza-tion and Synthesis of an ansa[3]-Ferrocenylamide

The discovery of new organometallic frameworks is of high interest for the field of bioorganometallic chemistry. In this work, to the best of our knowledge, we report the first synthesis of various N-metallocenyl ynamides and some of their reactivity. In particular, the use of hypervalent iodine(III) reagents triggered an unprecedented oxidative cyclization leading to ansa[3]-ferrocenyl compounds while the same reaction conditions with the ruthenocene analogues led to an acyclic acetoxy-adduct. The mechanism of the cyclization has been studied by means of DFT calculations, showing that it proceeds through a Concerted Iodination Deprotonation (CID) step. This study not only expands further the chemistry of ynamides but also opens up new avenues in bioorganometallic chemistry by providing an exclusive access to an original ferrocephane moiety to be employed in this research field.