Short-RInChIKey=SA-FUHFF-UHFFFADPSC-CMIRTBGZCF-UHFFFADPSC-NUHFF-NUHFF-NUHFF-ZZZ

Under an atmosphere of argon, to a solution of 3-ethyl-6-methoxy-5,7,8-trimethylchromen-2-one (23.0 mg, 93.3 µmol, 1.00 equiv.) in dichloromethane (1.74 ml), boron tribromide (1 M in DCM, 0.47 ml, 117 mg, 467 µmol, 5.00 equiv.) was added dropwise at –78 °C. At this temperature the reaction mixture was stirred for 30 min and then stirred at 21°C over night. The reaction was then quenched by addition of saturated NaHCO3 solution, extracted with dichloromethane and washed with distilled water and brine. The combined organic phases were dried over Na2SO4, filtrated and concentrated in vacuo.