It has long been noticed that the addition of inorganic salts to polar organometallic reagents can greatly affect and sometimes even dictate the reaction profiles of these reagents. For example the addition of halide salts to organozinc and organomagnesium reagents can significantly boost their reactivity.[1] Along with this activation effect, recent reports[2] have shown that introducing pivalate (OPiv) salts to these multicomponent mixtures, a new salt-effect has been realised, as trimetallic RZnOPiv�Mg(OPiv)X�nLiCl systems are not only more reactive towards C-C coupling processes than conventional organozinc reagents but also have a far enhanced resistance to air and moisture attack meaning they can be used efficiently for a time under air.Combining X-ray crystallographic, NMR (including DOSY) ESI-MS spectroscopic and reactivity studies, this talk will shed new light on the constitution of these intriguing pivalate-stabilized reagents.[3] These studies suggest that LiCl appears to have an activating effect on the reactivity of the organozinc reagent, while magnesium  pivalate contributes towards their air stability by sequestering H2O contaminants. This talk will also compare the effects on the reactivity and constitution of several Grignard reagents on addition of LiCl with those observed when metal-free halide salts (such as ammonium salts) are employed as additives.                     [1] (a) Clososki, G. C.; Rohbogner, C. J.; Knochel, P. Angew. Chem. Int. Ed. 2007 , 46, 7681; (b) Wunderlich, S. H.; Knochel, P. Angew. Chem. Int. Ed. 2007 , 46, 7685.[2] (a) Bernhardt, S.; Manolikakes, G.; Kunz, T.; Knochel, P. Angew. Chem. Int. Ed. 2011 , 50, 9205; (b) Stathakis, C. I.; Bernhardt, S.; Quint, V.; Knochel, P. Angew. Chem. Int. Ed. 2012 , 51, 9428.[3] Hern�n-G�mez, A.; Herd, E.; Hevia, E.; Kennedy, A. R.; Knochel, P.; Koszinowski, K.; Manolikakes, S. M.; Mulvey, R. E.; Schnegelsberg, C. Angew. Chem. Int. Ed. 2014 , 53, 2706.

Assessing salts-effects in organozinc and Grignard reagents: Reactivity, stabilization, and structural insights

248th National Meeting (2014)

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