Is the polarization of the C=C bond imperative for bifunctional outer-sphere C=C hydrogenation?

Understanding controlling factors is important for the development of bifunctional outer-sphere CC hydrogenations. A dominant view is that the polarization of CC bonds is imperative for these reactions. However, the present comparative DFT study suggests that the polarization of CC bonds is not the controlling factor. Instead, the "push-pull " type pi-conjugative effect can decrease activation barriers and contribute to outer-sphere bifunctional CC bond hydrogenations. What is more, this study shows the feasibility of the asymmetric bifunctional outer-sphere CC hydrogenation.