Furan → 4-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)furan-2-carboxamide

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Reaction Steps

3-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-furan (5.0 g, 25.77 mmol) is dissolved in dry acetonitrile (30 mL). Chlorosulfonylisocyanate (5.47 g, 38.65 mmol, 1.5 equiv.) in solution in dry acetonitrile (20 mL) is added in one portion at room temperature to the furan producing a pink solution that subsides overnight to turn yellow. The resulting solution is cooled with an ice bath and water (5 mL) is added, causing an exotherm. The resulting mixture is partitionned between DCM (100 mL) and water (30 mL). The aqueous layer is extracted 3 more times with DCM (50 mL), then the organic layers are gathered, washed with brine (10 mL), dried over anhydrous Na2SO4 and finally the solvent is removed under vacuum. The oily residue is dissolved in DCM (3 mL), sonicated to give a suspension of a crystalline solid. The solid is separated by filtration, and the cake is washed with a very small amount of DCM, then diethyl ether and dried under suction to afford 3 g of the title compound as a white powder.

Provenance & Evidence