Acetic Acid → 2-Chloro-5-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3-thiazole

Participants

Reaction Steps

Diisopropylamine (0.66 mL, 4.6 mmol) and triisopropylborate (1.26 mL, 5.44 mmol) were dissolved in 52 mL of anhydrous diethyl ether and then cooled to −90° C. n-Butyllithium (2.6 M in toluene, 1.77 mL, 4.6 mmol) was added slowly to the reaction and the mixture was stirred for 30 min. 2-Chlorothiazole (0.5 g, 4.18 mmol) was added and the reaction was allowed to gradually reach room temperature over 3 h. A solution of pinacol (0.69 g, 5.85 mmol) in 5 mL of diethyl ether was added. After 15 min, acetic acid (0.26 mL, 4.6 mmol) was added and the mixture was then filtered through Celite, rinsing with more diethyl ether. The filtrate was evaporated and the residue was distilled using a Kugelrohr apparatus at a temperature of 120-130° C. to give 0.84 g (82%) of 2-chloro-5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-thiazole.

Provenance & Evidence