Methyl N-(triethylammoniosulfonyl)carbamate → 1-((Trimethylsilyl)ethynyl)-2-(4-fluoro-3-methylphenyl)-4,4,6,6-tetramethylcyclohexene

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Reaction Steps

To a solution of the hydroxy acetylene from Example 1, Step C above (20 g, 55.5 mmol) in acetonitrile (250 ml) is added 20 g (83 mmol) of Burgess reagent. The reaction mixture is heated at reflux for 14 hours, cooled to room temperature and diluted with H2O (1 L). The aqueous solution is extracted with ether and the combined ether layers are washed with H2O. The ether fraction is dried over MgSO4 and the solvent is removed under reduced pressure. Purification by silica gel chromatography (100% hexane) provides 12.7 g (67%) of 1-((trimethylsilyl)ethynyl)-2-(4-fluoro-3-methylphenyl)-4,4,6,6-tetramethylcyclohexene as an oil: 1H NMR δ=0.0 (s,9), 0.95 (s,6), 1.15 (s,6), 1.4 ((s,2), 2.1 (s,2), 2.2 (s,3), 6.85 (t,1), 7.25 (m,2).

Provenance & Evidence