Triisopropyl borate → 3-cyano-1-cyclobutyl-6-cyclopropyl-1H-indol-2-ylboronic acid

Participants

Reaction Conditions

Reaction Steps

Into a solution of 1-cyclobutyl-6-cyclopropyl-1H-indole-3-carbonitrile (2.0 g, 8.47 mmol) and triisopropyl borate (3.52 mL, 15.25 mmol) in THF (35 mL) at −78° C. was added LDA (1.5 M in cyclohexane, 7.3 mL, 11.01 mmol). The mixture was stirred at −78° C. for 30 min, quenched with ice water (60 mL) and stirred for 15 min without cooling. The mixture was extracted with ethyl acetate 1:1 in hexane (20 mL). The aqueous layer was acidified with 2 N aq. HCl to pH 5 and then extracted with CH2Cl2 (60 mL). The organic layer was dried over Na2SO4 and concentrated to give the title compound as a solid (2.5 g, 70% pure by LCMS) that was used in the next step without further purification.

Provenance & Evidence