tert-Butyl acetate → t-Butyl [4-(1-methylpiperidin-4-ylidene)-4,10-dihydro-9-oxa-3-thiabenzo[f]azulen-2-yl]acetate

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Reaction Steps

Hexamethyldisilazane (11.97 g, 74.2 mmol) was ice-cooled in an argon atmosphere, and a 1.6 mol/L n-butyllithium-hexane solution (46.6 mL, 74.6 mmol) was added dropwise thereto. t-Butyl acetate (4.9 mL, 36.7 mmol) was added dropwise to the solution, and the mixture was stirred for 30 minutes. Pd(dba)2 (1.05 g, 1.8 mmol), N,N′-(2,6-diisopropylphenyl)dihydroimidazolium chloride (0.80 g, 1.9 mmol), and the compound obtained in Example 27 (7.0 g, 18.6 mmol) were added thereto, and the mixture was heated to room temperature, and stirred overnight. Water was added to the reaction mixture, and the product was extracted with ethyl acetate and dried over anhydrous sodium sulfate. The organic layer was distilled off under a reduced pressure, and the residue was purified by column chromatography (hexane:ethyl acetate=9:1), to give 3.30 g (43%) of the captioned compound in the form of an oily product.

Provenance & Evidence