2-Methyl-2-butene → 5-Phenylfuran-2-carboxylic acid

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Reaction Steps

To a solution of the product from Step 103a (0.650 g, 3.78 mmol, 1 eq) in water (5.5 mL), t-BuOH (18.0 mL), and THF (18.0 mL) is added 2-methyl-2-butene (3.2 mL, 30.2 mmol, 8 eq), potassium phosphate monobasic (1.54 g, 11.3 mmol, 3 eq), then NaClO2 (1.03 g, 11.3 mmol, 3 eq) in that order. After four hours, the reaction is complete and diluted with 1 N NaOH (100 mL). The aqueous solution is extracted with ether (2×100 mL), and the aqueous layer is acidified with conc. HCl. The resulting solution is extracted with CH2Cl2 (3×100 mL). The organic layers are dried over MgSO4, and the solvent removed. The product is purified by silica gel chromatography using a Biotage Flash 40M column (10% EtOAc/1% formic acid/heptane). The solid remaining after removal of the solvent is filtered and recrystallized from EtOH and water to give the acid as a white crystalline solid (0.499 g, 70.2%). HRMS (FAB) calculated for C11H8O3+H 189.0473, found 189.0403.

Provenance & Evidence