Two procedures for α-alkenylation and α-arylation of ketones, that permit, for the first time, introduction of a stereo-defined alkenyl group (E or Z) in the α-position of cyclic ketones in high yields with essentially complete retention (> 98%) of the alkenyl stereochemistry are reported. Furthermore, the one that is represented by Eq. 2 permits complete control of regiochemistry as well.