Ethanol → (4-Bromomethyl-1,6-dihydroxy-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl)-acetic acid ethyl ester

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Reaction Steps

To a solution of [1-hydroxy-4-methoxymethyl-6-(tetrahydro-pyran-2-yloxy)-1,3-dihydro-benzo[c][1,2]oxaborol-3-yl]-acetic acid ethyl ester from step 1.10. (870 mg, 1.37 mmol) in DCM (10 mL) was added boron tribromide (0.46 mL, 3.02 mmol) slowly under −78° C. The reaction mixture was allowed to stir at room temperature for 1 h. Ethanol was added slowly and the solvent was removed under vacuum. The crude product was used for next step without further purification. 1H NMR (300 MHz, CD3CN) δ 7.13 (s, 1H), 7.01 (s, 1H), 5.62 (dd, 1H), 4.42-4.63 (dd, 2H), 4.14 (q, 2H), 3.18-3.24 (dd, 1H), 2.40-2.51 (m, 1H), 1.22 (t, 3H).

Provenance & Evidence