Synthesis, X-ray structure and rearrangement of nitrogen ylides obtained upon alkyne and CO insertion reactions into aminocarbene complexes of chromium

Abstract

The aminocarbene complexes (CO)₅CrC(R¹)N(R²R³)1[R¹= H, Me, Ph, R²= Me, R²R³=(CH₂)₅, R³= Me, cyclopropyl] react with diphenylacetylene to give nitrogen ylides 5 which were fully characterized by an X-ray analysis carried out on 5a[(CO)₃CrR²R³N(C₁₆H₁₀OR¹)–(R¹= H, R²= R³=(CH₂)₅] and which lead, upon nitrogen to carbon migrations of alkyl groups R² and R³, to the expected lactams (e.g.8 and 9) C₁₆H₁₀ONR¹R²R³.