反应详情

To benzofuran-5-carbonitrile (500 mg, 3.49 mmol) in THF (9.98 mL) at −78° C. was added nBuLi 1.6M in hexanes (2.401 mL, 3.84 mmol) dropwise. The mixture was stirred for 30 min at this temperature, and then trimethyl borate (0.858 mL, 7.68 mmol) was added dropwise. The mixture was stirred for 20 min, and then HCl 2N (11.52 mL, 23.05 mmol) was added. The bath was removed, and stirring continued for 30 min. The mixture was diluted with water and extracted with EtOAc three times, dried over magnesium sulfate, filtered, concentrated. Crude 5-cyanobenzofuran-2-ylboronic acid (623 mg, 87%) was then dried and used as is for the next step.

1. stirringThe mixture was stirred for 20 min
2. customThe bath was removed
3. stirringstirring
4. waitcontinued for 30 min
5. additionThe mixture was diluted with water
6. extractionextracted with EtOAc three times
7. dry with materialdried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated
10. dry with materialCrude 5-cyanobenzofuran-2-ylboronic acid (623 mg, 87%) was then dried