Sulfoxonium, trimethyl-, iodide (1:1) → (5-Cyclopropyl-2-nitro-4-trifluoromethyl-phenyl)-carbamic acid tert-butyl ester

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Reaction Conditions

Reaction Steps

A mixture of (2-nitro-4-trifluoromethyl-5-vinyl-phenyl)-carbamic acid tert-butyl ester (Example A27) (1.66 g, 5 mmol), trimethylsulfoxonium iodide (2.75 g, 12.5 mmol) and benzyltriethylammonium chloride (200 mg, 0.878 mmol) in NaOH 50% (15 ml) and DCM (25 ml) was stirred at 23° C. for 2 days. The mixture was diluted with EtOAc and washed with 1N HCl, water and brine, dried over MgSO4. Removal of the solvent invacuum left a dark brown oil, which was purified by silica gel column chromatography to give the title compound a yellow solid (659 mg). Residual starting material was removed as follows: To a solution of the obtained material (659 mg, 1.9 mmol) in EtOAc (11.5 ml) and MeCN (11.5 ml), a solution of RuCl3 (30 mg, 0.133 mmol) and NaIO4 (610 mg, 2.85 mmol) in H2O (3.8 ml) was added under vigurous stirring at 0° C. The mixture was being stirred for a further 3 min and then quenched with a sat. sol. of Na2S2O3 (19 ml). The mixture was diluted with EtOAc, the aqueous layer was separated, extracted once with EtOAc. The combined EtOAc layers were washed with brine, dried over MgSO4 and charcoal, filtered over dicalite, evaporated and purified by column chromatography on silica gel (heptane/ethyl acetate 9:1) to yield a yellow solid (630 g, 36%).

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