2-Isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → 3-Methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzonitrile

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Reaction Steps

A solution of 4-bromo-3-methoxybenzonitrile (Combi-Blocks, San Diego, Calif., 2.500 g, 11.79 mmol) in 100 mL of diethyl ether was cooled to −78° C. and was treated with n-butyllithium (4.95 ml, 12.38 mmol). After stirring for 10 minutes, 2-isopropoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (3.07 ml, 16.51 mmol) was added, and the cooling bath was removed. After stirring for an additional 2 hours, LC/MS showed mostly product, so the reaction mixture was quenched with saturated NH4Cl solution. After stirring for 20 minutes, the reaction mixture was poured into a separatory funnel charged with EtOAc. The organic layer was separated, dried over MgSO4 and concentrated. Purification of the crude residue by silica gel column chromatography (0 to 100% EtOAc/heptane) gave 3-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzonitrile (1.62 g, 6.25 mmol, 53.0% yield) with minor impurities. m/z (ESI) 260.1 (M+H)+

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