Methanol → (9H-fluoren-9-yl)methyl 4-hydroxy-2-(hydroxymethyl)pyrrolidine-1-carboxylate
Reaction equation
[C:1]([N:18]1[CH2:25][C@H:24]([OH:26])[CH2:23][C@H:19]1[C:20](O)=[O:21])([O:3][CH2:4][CH:5]1[C:17]2[C:12](=[CH:13][CH:14]=[CH:15][CH:16]=2)[C:11]2[C:6]1=[CH:7][CH:8]=[CH:9][CH:10]=2)=[O:2].B.CSC.CO>C1COCC1>[C:1]([N:18]1[CH:19]([CH2:20][OH:21])[CH2:23][CH:24]([OH:26])[CH2:25]1)([O:3][CH2:4][CH:5]1[C:6]2[C:11](=[CH:10][CH:9]=[CH:8][CH:7]=2)[C:12]2[C:17]1=[CH:16][CH:15]=[CH:14][CH:13]=2)=[O:2]Participants
Reactant 3
Product 1
Reagents, catalysts & solvents 1
Procedure
To a solution of N-Fmoc-trans-4-hydroxy-L-proline (13.4 g, 38.1 mmol) in 250 ml THF was added borane-methyl sulfide (78 mmol, 5.78 g, 7.22 ml) dropwise at room temperature. After the evolution of H2 had ceased, the solution was heated to reflux with mechanical stirring. After 1 hour a white precipitate had formed. Methanol was carefully added, and the resulting solution refluxed for a further 15 minutes. The solution was cooled to room temperature, the solvents evaporated under reduced pressure, and the residual gum coevaporated with 2×100 ml methanol. The resulting crystalline product weighed 12.0 g (35.3 mmol, 93%). 1H NMR: (CDC13, 200 MHz) δ 7.85-7.25 (8H, m, ArH), 4.50-4.10 (5H, m, ArCHCH2, H3, H5), 3.80-3.40 (4H, m, 2 H2, 2 H6), 2.15-1.95 (1H, m, H2a), 1.80-1.60 (1H, m, H2b).
Workup
- temperaturethe solution was heated
- temperatureto reflux with mechanical stirring
- customAfter 1 hour a white precipitate had formed
- temperaturethe resulting solution refluxed for a further 15 minutes
- customthe solvents evaporated under reduced pressure
Sources & evidence
- ORD record
- ord-aedd631588a44e4ba45bf0562238ac7c
- Source dataset
- uspto-grants-2001_02
- Patent number
- US06184389B2
Reaction notes
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