We have discovered the unprecedented catalytic use of In(0) for catalytic C-C bond transformations. Remarkably, these general catalytic allylations of ketones proceeded smoothly in water as a sole solvent under mild conditions, and water proved to be essential for these reactions. Both the displayed substrate scope and the functional group tolerance were excellent. Importantly, the In metal catalyst could be easily recovered and reused without loss of catalytic activity. Moreover, when an alpha-adduct. Additionally, the resulting tertiary homoallylic alcohols were obtained with exceptionally high diastereoselectivities. The applicability of this concept to asymmetric catalysis in water by using In(0) combined with a chiral bis(oxazoline) ligand was demonstrated as well.