Divergent Fe-Mediated C-H Activation Paths Driven by Alkali Cations.

The association of the ferrous complex Fe II Cl 2 (dmpe) 2 ( 1 ) with alkali bases M(hmds) (M = Li, Na, K) proves to be an efficient platform for the activation of Ar-H bonds. Two mechanisms can be observed, leading to either Ar-Fe II species by deprotonative ferration or hydrido species Ar-Fe II -H by oxidative addition of transient Fe 0 (dmpe) 2 generated by reduction of 1 . Importantly, the nature of the alkali cation in M(hmds) has a strong influence on the preferred path. Starting from the same iron precursor, diverse catalytic applications can be explored by a simple modulation of the M I cation. Possible strategies enabling cross-coupling using arenes as pro-nucleophiles, reductive dehydrocoupling, or deuteration of B-H bonds are discussed.