Dess-Martin periodinane (31.18 g, 73.5 mmol) was added to a stirred solution of alcohol (86) (9.56 g, 36.8 mmol) in dichloromethane (110 mL) under an atmosphere of argon. The mixture was stirred at 30-35° C. for 5 hours, at ambient temperature for 16 hours, at 30-35° C. for 8 hours and at ambient temperature for 20 hours before adding Isolute® HM-N then removing the solvents in vacuo. Flash chromatography over silica, eluting with ethyl acetate:heptane mixtures 5:95 to 40:60 gave ketone (87) as a pale yellow oil (8.62 g, 91%).
