Phosphoric Acid → 2,2-Dimethyl-5-phenyl-4H-(1,3)benzodioxin-4-one

Participants

Reaction Conditions

Reaction Steps

0.23 g (0.2 mmol) of tetrakistriphenylphosphinepalladium is added under nitrogen to a solution of 2.93 g (9 mmol) of 2,2-dimethyl-5-trifluoromethylsulfonyloxy-4H-(1,3)benzodioxin-4-one in 50 ml of dimethylformamide, the mixture is stirred for a few minutes and 2.97 g (14 mmol) of potassium phosphate and 2.04 g (9.9 mmol) of diisopropyl phenylboronate are then added. The mixture is heated to 100° C. until conversion is complete (about 16 h). After cooling, the reaction solution is poured into a mixture of 250 ml of water and 6 g of orthophosphoric acid and extracted three times with methyl tert-butyl ether, and the combined organic phases are washed with water and saturated sodium chloride solution, dried over sodium sulfate and concentrated. 2.6 g of a dark oil remain, which is chromatographed on silica gel using toluene/acetone. 1.3 g (57%) of a colorless solid are obtained, m.p. 158°-163° C. (recrystallized from hexane).

Provenance & Evidence