Metal‐to‐Ligand Alkyl Migration Inducing Carbon–Sulfur Bond Cleavage in Dialkyl Yttrium Complexes Supported by Thiazole‐Containing Amidopyridinate Ligands: Synthesis,Characterization, and Catalytic Activity in the Intramolecular Hydroamination Reaction |
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| Authors: | Dr Dmitry M Lyubov Dr Lapo Luconi Dr Andrea Rossin Dr Giulia Tuci Anton V Cherkasov Prof Georgy K Fukin Dr Giuliano Giambastiani Prof Alexander A Trifonov |
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| Affiliation: | 1. G. A. Razuvaev Institute of Organometallic Chemistry of the Russian Academy of Sciences, Tropinina 49, GSP‐445, 603950 Nizhny Novgorod (Russia);2. Institute of Chemistry of Organometallic Compounds, ICCOM‐CNR, Via Madonna del Piano, 10, 50019 Sesto Fiorentino (Italy), Fax: (+39)?055‐5225203 |
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| Abstract: | Neutral YIII dialkyl complexes supported by tridentate N?,N,N monoanionic methylthiazole– or benzothiazole–amidopyridinate ligands have been prepared and completely characterized. Studies on their stability in solution revealed progressive rearrangement of the coordination sphere in the benzothiazole‐containing system through an unprecedented metal‐to‐ligand alkyl migration and subsequent thiazole ring opening. Attempts to synthesize hydrido species from the dialkyl precursor led to the generation of a dimeric yttrium species stabilized by a trianionic N?,N,N?,S? ligand as the result of metal‐to‐ligand hydride migration with chemoselective thiazole ring opening and subsequent dimerization through intermolecular addition of the residual Y?H group to the imino fragment of a second equivalent of the ring‐opened intermediate. DFT calculations were used to elucidate the thermodynamics and kinetics of the process, in support of the experimental evidence. Finally, all isolated yttrium complexes, especially their cationic forms prepared by activation with the Lewis acid Ph3C+B(C6F5)4]?, were found to be good candidate catalysts for intramolecular hydroamination/cyclization reactions. Their catalytic performance with a number of primary and secondary amino alkenes was assessed. |
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| Keywords: | hydroamination N ligands ring opening tridentate ligands yttrium |
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