Water → 5-(4,4,5,5-Tetramethyl-1,3,2-dioxaborolan-2-yl)thiophene-2-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 5-(dihydroxyboryl)-2-thiophenecarboxylic acid (4.0 g) in toluene (50 ml) was added pinacol (2.75 g). The reaction mixture was heated at 110-120° C. and the water set free during the reaction was continuously removed by a Dean-Stark apparatus. After 4 hours heating, the reaction mixture was cooled down to room temperature thus providing 5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-2-thiophene-carboxylic acid as a white solid which was filtered off (4.43 g, yield: 75%) and used as such for further reaction. The pure compound was characterized by its 1H NMR spectrum (300 MHz, CD3OD) as follows: peaks at 1.42 (12H, s), 7.63 (1H, d) and 7.89 (1H, d) ppm.

Provenance & Evidence