An umber of new magnesium and lithium silyl reagents were prepared and shown to be outstanding nucleophiles in reactions with industrially relevant fluoroolefins. These reactions result in an et transformation of either sp 2 or sp 3 CÀFbonds into CÀSi bonds by two modes of nucleophilic attack( S N VorS N 2'). The methods are mild, proceeding with high chemo-and regioselectivity.M echanistic pathways are described that lead to new substitution patterns from HFO-1234yf,H FO-1234ze,a nd HFO-1336mzz, previously inaccessible by transition metal catalyzeddifluorosilylation routes.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

A number of new magnesium and lithium silyl reagents were prepared and shown to be outstanding nucleophiles in reactions with industrially relevant fluoroolefins. These reactions result in a net transformation of either sp 2 or sp 3 C-F bonds into C-Si bonds by two modes of nucleophilic attack (SNV or SN2'). The methods are mild, proceeding with high chemo-and regioselectivity. Mechanistic pathways are described that lead to new substitution patterns from HFO-1234yf, HFO-1234ze and HFO-1336mzz, previously inaccessible by transition metal catalysed defluorosilylation routes.