Synthesis of a Stable N‐Hetero‐RhI‐Metallacyclic Silanone

Abstract

A novel N‐hetero‐Rh(I)‐metallacyclic silanone has been synthesized. This silanone, showing an extremely large dimerization energy (ΔG = +86.2 kcal/mol), displays considerable stability and persists in solution up to 60 °C. Above 120 °C, an intramolecular C(sp3)‐H insertion occurs slowly over a period of two weeks leading to the bicyclic silanol. The exceptional stability of the silanone, related to the unusual electronic and steric effects of Rh(I)‐substituent, should allow for a more profound study and understanding of these new species. Furthermore, the metallacyclic silanone presents two reactive centers (Si=O and Rh), which can be involved depending upon the nature of reagents. Of particular interest, the reaction with H2 starts with the hydrogenation of Rh(I) centre leading to the corresponding Rh(III)‐dihydride complex and it undergoes a cis/trans‐isomerization via a particular mechanism, demonstrating that addition‐elimination processes can also happen for silanones just like their carbon analogues!