Tetrabutylammonium Fluoride → (3aR,4S,5R,6aS)-4-(hydroxymethyl)-5-phenylmethoxy-3,3a,4,5,6,6a-hexahydrocyclopenta[b]furan-2-one

To a solution of (3aR,4S,5R,6aS)-hexahydro-4-(triisopropylsilyloxymethyl)-5-(phenylmethoxy)-2H-cyclopenta[b]furan-2-one (4, R1 is phenyl, R2 and R3 are H, and R8 is TIPS, 49 g, 0.117 mol) in tetrahydrofuran (7 vol) at 0° C. was added TBAF (128 mL, 0.129 mol) and the mixture was stirred for 2 h. After completion of the reaction, the reaction mixture was concentrated to dryness and purified by column chromatography [55% ethyl acetate in heptanes] to yield (3aR,4S,5R,6aS)-hexahydro-4-(hydroxymethyl)-5-(phenylmethoxy)-2H-cyclopenta[b]furan-2-one (5, R1 is phenyl, and R2 and R3 are H) in quantitative yield. 1H NMR (CDCl3): δ 2.12 (m, 3H), 2.53 (m, 2H), 2.74 (m, 2H), 3.51 (m, 2H), 3.89 (m, 1H), 4.48 (dd, J=47.9, 11.5 Hz, 2H), 4.92 (m, 1H), 7.27 (m, 5H).