Yield:-

Reaction Conditions:

with Triisopropyl borate;lithium diisopropyl amide in tetrahydrofuran;cyclohexane at 0 - 20; for 2.33333 h;

Steps:

1.2 Step 2
N-Boc-5-cyanoindole-2-boronic acid

The indole derivative in the THF is introduced into a 50 ml round-bottomed flask. The borate is added at room temperature under nitrogen, followed by dropwise addition over 20 minutes, at 0° C. under nitrogen, of the LDA. The mixture is stirred at 0° C. for 2 hours. The reaction medium is neutralized with 2N HCl and extracted with EtOAc. After drying and evaporating off the solvent, 829.3 mg of a brown foam containing 60% of the expected product, N-Boc-5-cyanoindole-2-boronic acid, and 40% of its Boc-free analogue, are obtained. This product is used without further purification for the coupling in Step 3.

References:

US2004/242559,2004,A1 Location in patent:Page 19