Tetrahydrofuran → 1-Benzoyloxy-3-hydroxymethyl-2-methylenecyclobutane

1-Benzoyloxy-2-bromomethyl-3-hydroxymethylcyclobutane (2.5 g, 8.36 mmol) from Step F and tetra-n-butylammonium fluoride ((8.1 g, 25 mmol) were combined in 200 mL of freshly distilled THF and the reaction mixture was stirred at ambient temperature, under a nitrogen atmosphere, overnight. The volume of the reaction mixture was then reduced to 25 mL and this was dissolved in 250 mL of methylene chloride. The methylene chloride solution was washed with 150 mL of water, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The residue (4.9 g) was dissolved in ~5 mL of methylene chloride and purified on a 2.5×35 cm silica gel column eluted @ 5 psi with a step-wise (4×200 mL steps) of methanol in methylene chloride from 0% to 3% methanol to give 1.54 g (85% yield) of the title compound as a syrup; 1H NMR (CDCl3) δ 2.38 (m, 2H), 3.22 (m, 1H), 3.69-3.85 (m, 2H), 5.13 (t, 1H), 5.32 (t, 1H), 5.79 (M, 1H), 7.45 (m, 2H), 7.58 (m, 1H), 8.08 (m, 2H); MS DCI-NH3M/Z: 219 (M+H)+, 236 (M+NH4)+.