Diisopropylamine → (4-Carboxybenzo[b]thiophen-2-yl)boronic acid

Participants

Reaction Conditions

Reaction Steps

A solution of n-BuLi (2.5M in hexane, 1.69 mol, 676 mL) is added slowly at −78° C. to a solution of diisopropylamine (1.69 mol, 236 mL) in 2 L of anhydrous THF. The mixture is stirred for 30 min. A solution of benzo[b]thiophene-4-carboxylic acid (0.8 mol, 143 g) in 2 L of anhydrous THF is added slowly and the mixture is allowed to reach 0° C. The reaction is cooled to −30° C. and the triisopropyl borate (2 mol, 463 mL) is added slowly. The cooling bath is removed and the mixture is allowed to reach room temperature. The reaction is quenched with 1.3 L of concentrated HCl and 1 L of water. The mixture is stirred overnight. The organic solvent is removed under reduced pressure. The precipitate is collected by filtration, washed with water, and dried under vacuum to yield the title compound (170.5 g, 96%). ES/MS m/e 221 (M−1).

Provenance & Evidence