7-[(5,5-Dimethyl-2-oxido-1,3,2-dioxaphosphinan-2-yl)­oxy]-4-methyl-2H-chromen-2-one

The title compound, C(15)H(17)O(6)P, was obtained from a reaction of 4-methyl-7-hy­droxy­coumarin and 2-chloro-5,5-dimethyl-1,3,2-dioxaphosphinane 2-oxide. There are two mol­ecules in the asymmetric unit in which the benzopyran ring system is almost planar [r.m.s. deviation for each molecule = 0.003 Å]. In the crystal, C—H⋯O hydrogen bonds and π–π stacking inter­actions [with centroid–centroid distances of 3.743 (3) and 3.727 (3) Å] link the two mol­ecules. The dioxaphospho­rinane ring adopts a chair conformation in both asymmetric molecules.