Backbone reactivity of lithium β-Diketiminate (NacNac) complexes with CO 2, tBuNCO and iPrNCO

Gauld, Richard M. and McLellan, Ross and Kennedy, Alan R. and Barker, Jim and Reid, Jacqueline and Mulvey, Robert E. (2019) Backbone reactivity of lithium β-Diketiminate (NacNac) complexes with CO 2, tBuNCO and iPrNCO. Chemistry - A European Journal, 25 (64). pp. 14728-14734. ISSN 0947-6539

[img] Text (Gauld-etal-CEJ2019-Backbone-reactivity-of-the-lithium-β-diketiminate-NacNac)
Gauld_etal_CEJ2019_Backbone_reactivity_of_the_lithium_diketiminate_NacNac.pdf
Accepted Author Manuscript
Restricted to Repository staff only until 1 October 2020.

Download (1MB) | Request a copy from the Strathclyde author

    Abstract

    Though alkali metal NacNac (β-diketiminate) complexes have been utilised in synthesis as NacNac-transfer agents, studies of them in their own right with small molecules are exceptionally rare. Here, the lithium compound of the common 2,6-diisopropylphenyl-β-methyldiketiminate [NacNac(Dipp, Me)] ligand is investigated with carbon dioxide and isocyanates. In all four cases reaction occurs at the backbone γ-C atom of the NacNac ligand, which redistributes electronically into a diimine. Insertion of CO 2 gives an eight-atom carboxylate (Li 2O 4C 2) ring at the γ-C site in a dimer. Insertion of tBuNCO gives a secondary amide at the γ-C site in a monomer with TMEDA chelating lithium. Double insertion of tBuNCO and (adventitious) oxygen gives a dimer with a (LiO) 2 central core involving the latter source. Insertion of less bulky (iPrNCO) gives a dimer with dimerisation through the C=O bonds of the emergent secondary amide function.