Phenylsilane → 5-(3,3-dimethyl-but-1-ynyl)-3-(N-tert-butoxycarbonyl-piperidin-4-yl)amino-thiophene-2-carboxylic acid methyl ester

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Reaction Steps

To a solution of 5-(3,3-dimethyl-but-1-ynyl)-3-amino-thiophene-2-carboxylic acid methyl ester (1.512 g, 5.97 mmol) and N-tert-butoxycarbonyl-piperidin-4-one (1.189 g, 5.97 mmol) in 2 mL of dry THF is added dibutyltin dichloride (181 mg, 0.60 mmol), and the mixture is stirred for 10 min at room temperature under nitrogen. Then phenylsilane (810 μL, 6.57 mmol) is added, and the mixture is stirred for 24 h at room temperature. Additional 595 mg of N-tert-butoxycarbonyl-piperidin-4-one, 90 mg of dibutyltin dichloride and 405 μL of phenylsilane are added, and the mixture is stirred for another 24 h. Then the mixture is diluted with CH2Cl2, washed with brine, organic fraction is separated, dried over Na2SO4, and concentrated to give 5.142 g of crude 5-(3,3-dimethyl-but-1-ynyl)-3-(N-tert-butoxycarbonyl-piperidin-4-yl)amino-thiophene-2-carboxylic acid methyl ester.

Provenance & Evidence