The diastereoselective synthesis of 1,3-diols by addition of oxygen nucleophiles to activated alkenes is presented. This review focuses on homoallylic alcohol substrates that react with a relay compound to form an intermediate oxygen nucleophile, which in turn will lead to a protected 1,3-diol by intramolecular addition to the olefin moiety. 1 Introduction 2 Base Catalysis 3 Organocatalysis 4 Activation with Non-Metallic Electrophiles 5 Activation with Transition Metal Derivatives 6 Conclusions