1,2-Oxazetidines have been utilized as formaldimine precursors for the direct aminomethylation of enamides under a Ru(ii) species. By merging alkenyl C-H activation with ring-opening of 1,2-oxazetidines, this efficient protocol provides a facile and novel approach to synthesize Z-selective aminomethyl substituted enamides. Furthermore, two exemplified synthetic elaborations highlight the potential of this transformation.