Carbenes Group 13 trialkyl complexes

Arduengo-type carbenes have also been successfully employed for complexation of group 13 trialkyls (Me3Ga- CNfPflCzMezNfPr1) 13091) and mixed hydrido/alkyls (Cp 2(H)Ga- CN(Me)C2Me2N(Me) 13192). Adduct 131... 

Milione et al. reacted the same phenoxyimino functionalised imidazolium salt with trialkyl alanes in an attempt to form the corresponding carbene complex of aluminium(III) [71] (see Figure 4.19). Reaction of the phenoxyimino functionalised imidazolium salt with AIMOj proceeds smoothly with the hydroxy group reacting with the alane under elimination of methane. The imidazolium end does not react under methane elimination, but remains pendant. Aluminium carbene adducts are still rare [72-75] and are usually synthesised by a reaction between the alane and the free carbene. 

The groups of Siebert " and Erker " studied the reactivity toward a strong base of imidazole-borane adducts, showing that for the BH3 moiety the anionic 3-boraneimidazol-2-yhdene could be isolated (structure 25 in Scheme 31), whereas migration of BR3 (R = Et, C Fs) groups to the carbene carbon atom was observed for trialkyl- or triarylborane reagents (complex 26 in Scheme 31). 

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