ω-Hydroxy ketones and diketones, which are important starting materials for the synthesis of cycloalkanones and heterocyclic compounds, were prepared by the one-step reaction of methyl ketones with α, ω-diols under the influence of an iridium complex and a base. The selectivity of ω-hydroxy ketones and diketones could be controlled by varying the starting ratio of methyl ketones to α, ω-diols. For example, reaction using acetophenone (5 equiv) ...