GENERAL METHODS: Catechol (1 mmol) was dissolved in acetonitrile (5 mL) and a magnetic stirrer was added to form a magnetically stirred solution. Subsequently, OXBTEATB (0.233 g, 0.5 mmol) was added to the solution and the reaction was stirred at room temperature for the reaction time referred to in Table 1.The reaction progress was monitored by thin layer chromatography (TLC) with an eluent ratio of hexane/ethyl acetate (5:1). Upon completion of the reaction, OXBTEATB was removed by filtration, and the filtrate was transferred to a partition funnel and extracted sequentially with water (15 mL) and dichloromethane (20 mL). The organic layer was collected and dried with anhydrous Na2SO4 and subsequently concentrated in a rotary evaporator to remove solvent. The crude product was purified by silica gel column chromatography, the eluent being a solvent mixture of hexane and ethyl acetate. To regenerate the reagents, the resulting white solid was treated with liquid bromine. The structures of all products were confirmed by determination of melting points or 1H NMR spectra and comparison with data reported in the literature [29a-29e].
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