Total Synthesis of Altissimacoumarin D, a Small Molecule Sirtuin1 Activator

The total synthesis of the plant natural product altissimacoumarin D was achieved by the Mitsunobu alkylation of isofraxidin by geraniol. Isofraxidin was prepared from 2,4-dihydroxybenzaldehyde in five steps. The key reaction was the Knoevenagel condensation of an ortho-hydroxybenzaldehyde with Meldrum's acid under neutral conditions in water and one-pot acid catalyzed cyclization to the coumarin.