Sodium periodate saturated water (2.2 mL) was added to a solution of the diol 4 (146 mg, 0.36 mmol) in methanol (9 mL) at 0° C. The solution was stirred at 0° C. for 1 h, poured into brine and extracted with ether and benzene. The organic extracts were combined, washed with brine, dried (MgSO4) and evaporated. An oily residue was dissolved in hexane (1 mL) and applied on a silica Sep-Pak cartridge. Pure 4-methylenecyclohexanone derivative 5 (110 mg, 82%) was eluted with hexane/ethyl acetate (95:5) as a colorless oil: 1H NMR (CDCl3) δ 0.050 and 0.069 (6H and 6H, each s, 4×SiCH3), 0.881 (18H, s, 2×Si-t-Bu), 2.45 (2H, ddd, J=14.2, 6.9, 1.4 Hz), 2.64 (2H, ddd, J=14.2, 4.6, 1.4 Hz), 4.69 (2H, dd, J=6.9, 4.6 Hz), 5.16 (2H, s); MS m/z (relative intensity) no M+, 355 (M+-Me, 3), 313 (M+-t-Bu, 100), 73 (76).
