Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... MgO was used for the first time as a heterogeneous basic catalyst to synthesize β-keto-1,3-dithianes, potentially useful synthetic intermediates, from conjugated ynones and ynoates. ... High surface area magnesium oxide, MgO, is an excellent catalyst for triggering the double Michael addition of 1,3- ...