Iodine → 2Iodo-3,6-dimethoxy-2',4',6'-trimethylbiphenyl

Participants

Reaction Conditions

Reaction Steps

To an oven-dried 500-mL round bottom flask equipped with a magnetic stir bar was added 2-fluoro-1,4-dimethoxybenzene (6 g, 38.4 mmol, 1 equiv). The flask was purged with N2, and anhydrous degassed tetrahydrofuran (250 mL) was added. The solution was cooled to −78 ° C., and n-butyllithium (15.4 mL, 38.4 mmol, 1 equiv, 2.5 M in hexanes) was added dropwise over 12 minutes The mixture was stirred for another 30 minutes, and mesitylmagnesium bromide (38.4 mL, 38.4 mmol, 1 equiv, 1M tetrahydrofuran) was slowly added over 16 minutes. The reaction mixture was stirred at −78 ° C. for an additional hour, then removed from the cold bath to warm to room temperature. After 2 hours at room temperature, the reaction mixture was cooled in an ice bath to 0 ° C. and added a fresh solution of iodine (46.1 mL, 46.1 mmol, 1.2 equiv, 1M in tetrahydrofuran) was added dropwise over 10 minutes. The flask was removed from the ice bath and stirred for an additional hour. Then the reaction mixture was concentrated to afford a red oil. The oil was dissolved in dichloromethane (100 mL), washed with aqueous saturated sodium thiosulfate (2 ×50 mL) and brine (50 mL), dried over sodium sulfate, filtered, and concentrated to furnish a brown-yellowish oil. Purification of the crude product by column chromatography (330-g column; gradient: 1.5 column volumes heptane, ramp up to 89:11 heptane:ethyl acetate over 8 column volumes, hold at 89:11 for 2 column volumes) followed by crystallization in heptane (20 mL) and a minimal amount of methyl tert-butyl ether, filtration, washing with cold heptane, and drying under vacuum afforded the title compound (6.64 g, >99 area % by HPLC, 45% yield). 1H NMR (400 MHz, CDCl3) δ ppm 6.99-6.96 (m, 2H), 6.94 (d, J=8.9 Hz, 1H), 6.82 (d, J=8.9 Hz, 1H), 3.90 (s, 3H), 3.69 (s, 3H), 2.37 (s, 3H), 1.93 (s, 6H). 13C NMR (100 MHz, CDCl3) δ ppm 152.4, 150.9, 137.6, 136.7, 135.8, 135.3, 127.7, 110.9, 109.3, 94.5, 56.9, 56.4, 21.6, 20.1.

Provenance & Evidence