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ChemicalBook CAS DataBase List Benzofuran-2-boronic acid
98437-24-2

Benzofuran-2-boronic acid synthesis

9synthesis methods
2-Bromobenzofuran (5.0 mmol) was dissolved in dry 20 mL of tetrahydrofuran, and the mixture was cooled to -78 degrees C. n-Butyllithium (5.5 mmol, 2.43 M, 1.1 eq.) was then added slowly and dropwise to the mixture, and the reaction mixture was stirred for
-

Yield:-

Reaction Conditions:

Stage #1:1-benzofurane with n-butyllithium in tetrahydrofuran;hexane at -78; for 1 h;
Stage #2:Triisopropyl borate in tetrahydrofuran;hexane at -78 - 20;
Stage #3: with hydrogenchloride in tetrahydrofuran;hexane;water; pH=5 at 20;

Steps:

6-(tert-Butyl-dimethylsilanyloxy)benzofuran-2-boronicacid
General procedure: n-Butyllithium 2.4M inhexanes (2.5 mL, 6.0 mmol) was added slowly to a solution of 32 (1143 mg, 5.0 mmol) in dry THF (20mL) at -78°C. After 1h stirring at -78°C,triisopropylborate (1.4 mL, 6.0 mmol)was added dropwise and the mixture was stirred for another 30 min at -78°C.2Then the mixture was stirred at room temperature for 30 min. This mixture wastreated with 2 N aqueous HCl (6 mL) at room temperature and then poured inwater (20 mL). The resulting aqueous solution was extracted with portions ofethyl acetate (3×20 mL), the organic layer was washed with brine, dried overanhydrous sodium sulfate, filtered and concentrated under vacuum to afford theproduct 33 (1430 mg, yield 98%) as awhite solid, which was used directly in the next step without furtherpurification.

References:

Wu, Deyan;Mei, Hanbing;Tan, Ping;Lu, Weiqiang;Zhu, Jin;Wang, Wei;Huang, Jin;Li, Jian [Tetrahedron Letters,2015,vol. 56,# 29,p. 4383 - 4387] Location in patent:supporting information

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