Cesium carbonate → methyl(1S,4R)-4-{5-[3-({[tert-butyl(dimethyl)silyl]oxy}methyl)-5-nitrophenyl]-1,3-thiazol-2-yl}-4-hydroxy-2,2-dimethylcyclohexanecarboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirring solution of the product of Step 2 (7.91 g, 20.1 mmol) in dioxane (30 mL) and water (4 mL) was added methyl(1S,4R)-4-(5-bromo-1,3-thiazol-2-yl)-4-hydroxy-2,2-dimethylcyclohexanecarboxylate (5 g, 14.4 mmol) and cesium carbonate (14 g, 43.1 mmol). The solution was deoxygenated, then tris(dibenzylideneacetone)dipalladium(0) (0.66 g, 0.72 mmol) and 2-(dicyclohexylphosphino)-2′,4′,6′-triisopropylbiphenyl (0.68 g, 1.44 mmol) were added and the mixture was stirred at 100° C. for 15 h. The mixture was cooled to room temperature and quenched with 1:1 saturated aqueous sodium bicarbonate:brine. The mixture was extracted with ethyl acetate, and the organic layer was dried over sodium sulfate, filtered, and concentrated. Purification by flash chromatography on silica gel (0-50% ethyl acetate in hexanes) afforded methyl(1S,4R)-4-{5-[3-({[tert-butyl(dimethyl)silyl]oxy}methyl)-5-nitrophenyl]-1,3-thiazol-2-yl}-4-hydroxy-2,2-dimethylcyclohexanecarboxylate (4.4 g, 7.82 mol, 54% yield) as an orange oil. MS ESI: [M+H]+ m/z 535.2.

Provenance & Evidence