Water → 7-Fluoro-2,3-dihydrobenzo[b][1,4]dioxine-6-carbaldehyde

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Reaction Steps

To a solution of 6-fluoroveratraldehyde (1.2 g, 6.2 mmol) in CH2Cl2 (62 mL) was added BBr3 (6.2 mL, 62 mmol) and the solution was stirred at RT for 4 h. The solution was then cooled to 0° C., diluted with EtOAc (120 mL) and slowly treated with H2O (60 mL). The organic layer was washed with brine (2×100 mL), dried, filtered and concentrated to provide the desired catechol intermediate as a dark brown solid (1.0 g, 6.4 mmol). This solid was immediately treated with 1,2-dibromoethane (0.60 mL, 7.1 mmol) and heated to 100° C. The suspension was treated with NaOH (0.50 g, 13 mmol) in H2O (30 mL) dropwise over 1 h and stirred at 100° C. for 2 days. The suspension was then filtered. The collected solid was re-suspended in CHCl3 and filtered. The filtrate was concentrated to provide 0.22 g (19%) of the title compound as a tan solid. MS (ESI): exact mass calculated for C9H7FO3, 182.04; m/z not found. 1H NMR (500 MHz, CDCl3): 10.21 (s, 1H), 7.35 (d, J=6.7, 1H), 6.66 (d, J=10.9, 1H), 4.33 (m, 2H), 4.25 (m, 2H).

Provenance & Evidence