A methylene chloride (200 mL) solution of 4-oxocyclohexyl benzoate [Macromolecules 2000, 33, 4619] (17.2 g, 84.5 mmol) in N,N-diisopropylethylamine (29.4 mL, 169 mmol) was cooled in an ice bath under nitrogen. A methylene chloride (50 mL) solution of tert-butyldimethylsilyl trifluormethanesulfonate (20.3 mL, 88.7 mmol) was added dropwise over 0.5 h. After warming to room temperature the contents of the reaction flask were poured into water. The organic layer was separated, dried with anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. Flash column chromatography (hexane:ethyl acetate, 95:5) gave a pale oil (23.2 g, 86% yield).
