Experimental Crystal data

R factor = 0.083; wR factor = 0.289; data-to-parameter ratio = 12.8. The title compound, C21H14O3, crystallizes with eight independent molecules (A–H) in the asymmetric unit which are arranged in four groups of two molecules each (AB, CD, EF and GH). In each molecule, the pyran-2-one ring is planar (r.m.s. deviations vary from 0.001 to 0.017 Å), while the pyran ring has a screw-boat conformation. In the crystal, molecules stack in two columns, along the [101] direction, composed o