Diisoamyl (1R,4S)-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate (2) was prepared by reacting exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride (1) with isoamyl alcohol in the presence of a sulfuric acid catalyst under sonication conditions. Compound 2 was characterized by 1H, 13C NMR, DEPT-135, infrared, and UV-vis spectroscopy. Gas chromatography–mass spectrometry, elemental analysis, and melting point determination were used to assess purity. The structure of compound 2 was also determined by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group P21/c (14) with cell values of a = 15.5647(3) Å, b = 12.8969(2) Å, c = 9.0873(2) Å; β= 99.3920(10)°.
