2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → 2-(3,4-Dimethoxy-2-methoxymethoxyphenyl)-4,4,5,5-tetramethyl[1,3,2]dioxaborolane

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Reaction Conditions

Reaction Steps

The MOM-protected phenol 1a (10 g; 0.0505 mol) was dissolved in 1000 ml of dry diethyl ether and cooled to −78° C. A solution of n-butyl lithium (22.2 ml of 2.5 M) was then added via syringe. The cooling bath was removed and the solution was allowed to warm to room temperature. After stirring the solution at room temperature for two hours, a yellow precipitate was observed. The mixture was cooled to −78° C., and 15 ml of 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.080 mol) was added via syringe. The cooling bath was removed after two hours. Stirring was continued for four hours at room temperature. The mixture was then poured into 300 ml of water and extracted several times with diethyl ether (3×300 ml), dried (Na2SO4), and concentrated to a yellow oil (12.37 g, 76%) that was used without further purification: 1H NMR: (300 MHz, CDCl3): 7.46 (d, 1H, J=8.4 Hz); 6.69 (d, 1H, J=8.4 Hz); 5.15 (s, 2H); 3.87 (s, 3H); 3.83 (s, 3H); 1.327 (s, 12H).

Provenance & Evidence