(4R)-3-Hy­droxy-7-isopropyl-4-methyl-5,6-di­hydro­benzo­furan-2(4H)-one

In the title compound, alternatively called α-hy­droxy-γ-alkyl­idenebutenolide, C₁₂H₁₆O₃, two independent mol­ecules (A and B) crystallize in the asymmetric unit in each of which the 5,6-di­hydro­benzo ring has an envelope conformation. The torsion angle along the butadiene chain in the γ-alkyl­idenebutenolide core is −177.9 (2)° for mol­ecule A and 179.9 (2)° for mol­ecule B. In the crystal, O—H...O hydrogen bonds between hy­droxyl and carbonyl groups of adjacent independent mol­ecules form dimers with R²₂(10) loops.