2 g 548 mmol followed by heating to reflux for 1 hour the solvent was evaporated in vacuo and the residue was taken up into ethyl ether filtered washed with saturated potassium carbonate solution brine 1n citric acid solution and brine the organic phase was dried over anhydrous magnesium sulfate and filtered through charcoal the filtrate was concentrated in vacuo giving a crystalline precipitate which was filtered washed with hexane and dried in vacuo to a solid this material was distilled at 2 mm hg 125 u00b0 c giving a crystalline solid 21 7 g 52 yield nmr spectra and elemental analysis were consistent with the structure to tetrahydrofuran 40 ml was added magnesium turnings 2 33 g 95 8 mmol 1 bromo 3 4 methylenedioxy 5 methoxybenzene 21 7 g 93 9 mmol and a catalytic amount of iodine following vigorous reaction the metal was consumed and the solution was added to a solution of trimethylborate 38 ml 334 mmol in tetrahydrofuran 100 ml at u2212 78 u00b0 c over 45 minutes the mixture was stirred at u2212 78 u00b0 c for an additional 2 hours then at 25 u00b0 c overnight to the mixture was added 1n hcl 200 ml followed by stirring at 25 u00b0 c for 3 days the.