Trimethyl borate → [2-Methoxy-5-[4-(methoxycarbonyl)-2-methylphenyl]phenyl]boronic acid

Participants

Reaction Conditions

Reaction Steps

Into a 10000-mL 4-necked round-bottom flask purged and maintained with an inert atmosphere of nitrogen was placed a solution of methyl 4-(3-iodo-4-methoxyphenyl)-3-methylbenzoate (600 g, 1.57 mol, 1.00 equiv) in tetrahydrofuran (5000 mL). This was followed by the addition of isopropyl magnesium chloride (960 mL, 1.20 equiv) dropwise with stirring at <−25° C. over 60 min. The reaction was maintained for 1 h at −15° C., followed by addition of trimethyl borate (329.2 g, 3.17 mol, 2.00 equiv) dropwise with stirring at <−20° C. over 30 min. The resulting solution was stirred for 60 min at <0° C., then quenched by the addition of 5000 mL of H3PO4 (aq. 1M). The bulk of THF was removed under vacuum. The solid was collected by filtration and washed with 2×200 ml of toluene. This resulted in 300 g (crude) of [2-methoxy-5-[4-(methoxycarbonyl)-2-methylphenyl]phenyl]boronic acid as a yellow solid.

Provenance & Evidence