Reaction equation
[O:1]=[C:2]1[NH:6][C@H:5]([C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH2:4][CH2:3]1.C[Si](C)(C)[N-][Si](C)(C)C.[Li+].Br[CH2:23][C:24]1[CH:29]=[CH:28][C:27]([B:30]2[O:34][C:33]([CH3:36])([CH3:35])[C:32]([CH3:38])([CH3:37])[O:31]2)=[CH:26][CH:25]=1.C(O)(=O)C>O1CCCC1.C1(C)C=CC=CC=1>[O:1]=[C:2]1[NH:6][C:5]([CH2:23][C:24]2[CH:25]=[CH:26][C:27]([B:30]3[O:31][C:32]([CH3:38])([CH3:37])[C:33]([CH3:36])([CH3:35])[O:34]3)=[CH:28][CH:29]=2)([C:7]([O:9][CH2:10][CH3:11])=[O:8])[CH2:4][CH2:3]1Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 2
Conditions
- Temperature
- -78 °C
Procedure
Ethyl (2S)-5-oxopyrrolidine-2-carboxylate (0.200 g, 1.27 mmol) was azeotroped three times from toluene (25 mL each), dissolved in tetrahydrofuran (4.4 mL) and cooled to −78° C. 1 M lithium hexamethyldisilazide in tetrahydrofuran (1 M, 3.75 mL) was added via syringe and the colorless solution was stirred 30 min before addition of 2-[4-(bromomethyl)phenyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.4 g, 1.0 mmol) in tetrahydrofuran (2.0 mL). The slightly yellow solution was stirred at −78° C. for 30 min and then at −10° C. for 1 h and warmed to rt for an additional 1 h before it was cooled back to −78° C. and quenched with acetic acid (1.00 mL, 17.6 mmol). Evaporation and purification by preparative LCMS gave the desired product as a colorless glass, (296 mg, 62%). 1H NMR (400 MHz, CD3OD): δ 7.67 (d, J=7.4 Hz, 2H), 7.22 (d, J=7.4 Hz, 2H), 4.20 (q, J=7.2 Hz, 2H), 3.08 (d, J=13.0 Hz, 1H), 3.05 (d, J=13.0 Hz, 1H), 2.35 (m, 1H), 2.23 (m, 1H), 2.15 (m, 1H), 1.79 (m, 1H), 1.35 (s, 12H), 1.25 (t, J=7.0 Hz, 3H); LCMS found for C20H29BNO5 (M+H)+: m/z=374.
Workup
- waitat −10° C. for 1 h
- temperaturewarmed to rt for an additional 1 h before it
- temperaturewas cooled back to −78° C.
- customEvaporation and purification by preparative LCMS
Sources & evidence
- ORD record
- ord-cfa8b9df50894377a2779d5199dbe6c5
- Source dataset
- uspto-grants-2006_11
- Patent number
- US07141596B2
Linked notes
Loading…