Triisopropyl borate → 5-Butyl-2-(N-tert-butylaminosulfonyl)thiophene-3-boronic acid

Participants

Reaction Conditions

Reaction Steps

5-Butylthiophene-2-sulfonic acid tert-butylamide (2.9 g, 0.010 mol, see step (a) above) was dissolved in THF (40 mL) under N2 and then cooled to −78° C. n-BuLi (1.6 M, 16.2 mL, 0.026 mol) was added via a syringe. The reaction mixture was stirred at −20° C. for 4 hours. Tri-iso-propylborate (13.3 mL, 0.058 mol) was then added via a syringe and the reaction mixture was stirred overnight at room temperature. The reaction was quenched with 2 M HCl (20 mL). The organic phase was separated and the water phase was extracted with EtOAc (3×100 mL). The combined organic phase was washed with brine and dried and concentrated in vacuo. The product was used in the next step without further purification.

Provenance & Evidence