Diiodomethane → Spiro[4H-1-benzopyran-4,1′-cyclopropane]-6-carboxylic acid, 2,3-dihydro-2,2-dimethyl-, methyl ester

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Reaction Steps

To a mixture of methyl 2,2-dimethyl-4-methylidene-3,4-dihydro-2H-chromene-6-carboxylate (34.0 mg, 0.15 mmol) and diethylzinc (1.17 mL, 1.17 mmol) in toluene (2.90 mL) under N2 atmosphere was added diiodomethane (189 μL, 2.34 mmol) dropwise via a syringe at room temperature. The mixture was stirred at room temperature overnight and then partitioned between diethyl ether (10.0 mL) and 5% aqueous HCl (10.0 mL). The aqueous layer was extracted with diethyl ether (20.0 mL, 2×). The combined organic layers were dried over Na2SO4, filtered and concentrated under vacuum. The crude residue was purified by silica gel chromatography eluting with 0-15% EtOAc/hexanes to afford the desired product as a pale-yellow solid.

Provenance & Evidence