A resealable tube was charged with 4-(4-bromophenoxy)butyric acid (259 mg, 1.0 mmol), 5,5,5′,5′-Tetramethyl-[2,2′]bi[[1,3,2]dioxaborinanyl] (249 mg, 1.1 mmol), potassium acetate (245 mg, 2.5 mmol), and DMSO (2 mL). The resulting orange suspension was deoxygenated by sparging with nitrogen gas. Dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium(II) dichloromethane adduct (30 mg, 0.041 mmol) was added, and the tube was sealed tightly and heated at 80° C. overnight. Hydrochloric acid (1N) was added, and the mixture was extracted with EtOAc (2×), washed with water (2×) and brine (1×), and dried (MgSO4). The organic layer was concentrated in vacuo and the residue purified by flash chromatography (0 to 15% MeOH in DCM) to give the 2,2-dimethyl-1,3-propanediol boronic ester of 1A. This material was dissolved in diethyl ether and washed with NaOH (2 N, 2×). The aqueous layers were washed with diethyl ether, combined, and acidified to pH 4 with hydrochloric acid (6 N). The resulting solid precipitate was collected by filtration to afford 1A (210 mg, 94%) as a beige solid. 1H NMR (400 MHz, CD3OD) δ 2.06 (m, 2H), 2.48 (t, J=7.5 Hz, 2H), 4.02 (t, J=6.6 Hz, 2H), 6.88 (br s, 2H), 7.62 (br d, 2H).
