Triisopropyl borate → 5-Cyanothiophene-2-boronic acid

Participants

Reaction Steps

To a solution of compound thiophene-2-carbonitrile (10 g, 9.16 mmol, 1.0 eq) and tri-iso-propylborate (23 mL, 100 mmol, 1.09 eq) in dry THF (300 mL) under nitrogen at −78° C., potassium hexamethyldisilazide (1 M in THF, 100 mL, 100 mmol, 1.09 eq) was added dropwise. After 1 h, the reaction was quenched with 1 N HCl (200 mL), stirred for 30 min and extracted with ethyl acetate. The combined organic layers were washed with water, dried (Na2SO4), filtered and evaporated and crystallized with petroleum ether/ethyl acetate to afford the product compound 5-cyanothiophen-2-ylboronic acid (7.4 g, 53%). LC-MS (m/z)=153.9 [M+H]+

Provenance & Evidence