Reaction #7108

Reaction equation

tris-iso-propylborate

5-bromo-spiro[cyclopentane-1,3′-[3H]indol]-2′(1′H)-one

sodium hydride

HCl

butyl lithium

→

subtitled compound

Yield 64.0%

(Spiro[cyclopentane-1,3′-[3H]indol]-2′(1′H)-one-5-yl) boronic acid

Yield 64.0%

Solvents

THF

Conditions

Workup

1. 1
   workup.WAITAfter 30 minutes
2. 2
   Otherwas slowly brought to room temperature
3. 3
   Extractionextracted with EtOAc (×3)
4. 4
   OtherThe organic layers were collected
5. 5
   Washwashed with 1N HCl, water
6. 6
   Dryingdried (MgSO4)
7. 7
   Otherevaporated

Procedure

To a solution of 5-bromo-spiro[cyclopentane-1,3′-[3H]indol]-2′(1′H)-one (13.1 g, 53 mmol) in anhydrous THF (300 cm3) under N2, was added sodium hydride (60% in mineral oil, 2.1 g, 53 mmol). After 30 minutes, the reaction mixture was cooled to −78° C. and butyl lithium (2.5 M in hexanes, 22 cm3, 53 mmol) was added slowly. After 30 minutes, tris-iso-propylborate (34 cm3, 146 mmol) was added, and the reaction mixture was slowly brought to room temperature, and stirred for 14 hours. The reaction mixture was poured into 1N HCl and extracted with EtOAc (×3). The organic layers were collected and washed with 1N HCl, water, dried (MgSO4) and evaporated to give the subtitled compound (7.8 g, 64%) as a tan solid which was used without further purification. 1H NMR (DMSO-d6) δ 10.3 (s, 1H), 7.9 (s, 1H), 7.7–7.6 (m, 2H), 6.8 (d, 1H, J=7.7 Hz), 3.4 (s, 1H), 2.0–1.7 (m, 8H); MS (FI-POS) m/z @231.

Source