Synthesis, crystal structure and absolute configuration of (3aS,4R,5S,7aR)-7-(but-3-en-1-yn-1-yl)-2,2-dimethyl-3a,4,5,7a-tetra-hydro-2H-1,3-benzodioxole-4,5-diol.

The absolute configuration of the title compound, C13H16O4, determined as 1S,2R,3S,4R based on the synthetic pathway, was confirmed by single-crystal X-ray diffraction. The mol-ecule is a relevant inter-mediary for the synthesis of speciosins, ep-oxy-quinoides or their analogues. The mol-ecule contains fused five- and six-membered rings with two free hydroxyl groups and two protected as an iso-propyl-idenedioxo ring. The packing is directed by hydrogen bonds that define double planes of mol-ecules laying along the ab plane and van der Waals inter-actions between aliphatic chains that point outwards of the planes.