Sodium bis(trimethylsilyl)amide → Dibenzyl-4-methyleneheptanedioate

HRID 549651Notes

Reaction equation

HRID 549651 reaction equation
[CH3:1][Si]([N-][Si](C)(C)C)(C)C.[Na+].[CH2:11]([O:18][C:19](=[O:36])[CH2:20][CH2:21][C:22](=O)[CH2:23][CH2:24][C:25]([O:27][CH2:28][C:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1)=[O:26])[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C1COCC1.O>[CH2:11]([O:18][C:19](=[O:36])[CH2:20][CH2:21][C:22](=[CH2:1])[CH2:23][CH2:24][C:25]([O:27][CH2:28][C:29]1[CH:34]=[CH:33][CH:32]=[CH:31][CH:30]=1)=[O:26])[C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1

Participants

6

Reactant 2

HCID 2724254Sodium bis(trimethylsilyl)amideHCID 14639376Dibenzyl-4-oxopimelate

Product 1

HCID 67191800Dibenzyl-4-methyleneheptanedioateYield 56%

Reagents, catalysts & solvents 3

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 962WaterSolventHCID 8028TetrahydrofuranSolvent3×

Conditions

Temperature
0 °C

Procedure

Methyltriphenylphosphonium bromide (536 mg, 1.5 mmol) was suspended in anhydrous THF (1.0 mL) at −5C. A THF solution of NaHMDS (1.0 M, 1.5 mL, 1.5 mmol) was added dropwise to keep the temperature below 0° C. The mixture was stirred at 0° C. for 0.5 h before cooled to −78° C. To this ylid solution was added a solution of dibenzyl-4-oxopimelate (354 mg, 1.0 mmol) in THF (1.0 mL) dropwise to keep the temperature below −50° C. The temperature was allowed to rise to room temperature in 1.5 h with stirring after addition. The reaction mixture was then poured in icy water (25 mL) and extracted with Et2O (2×25 mL). The organic layer was washed with brine (20 mL) and dried over Na2SO4. The solvent was removed under vacuum and the residue was subjected to silica chromatography (EtOAc/hexanes, up to 1/10) to give compound B4 (197 mg). The yield was 56%. 1H NMR (200 MHz, CDCl3) δ 7.37 (m, 10H), 5.11 (s, 4H), 4.78 (d, 2H, J=1.1 Hz), 2.53 (m, 4H), 2.39 (m, 4H); 13C NMR (50 MHz, CDCl3) δ 173.3, 146.6, 136.4, 129.0, 128.7, 110.5, 66.9, 33.2, 31.6; MS (MALDI-TOF) calcd (M+Na+) 375.4, found 375.6.

Workup

  1. customthe temperature below 0° C
  2. temperaturebefore cooled to −78° C
  3. customthe temperature below −50° C
  4. waitto rise to room temperature in 1.5 h
  5. stirringwith stirring
  6. additionafter addition
  7. extractionextracted with Et2O (2×25 mL)
  8. washThe organic layer was washed with brine (20 mL)
  9. dry with materialdried over Na2SO4
  10. customThe solvent was removed under vacuum

Sources & evidence

ORD record
ord-55453abdb9bf405890f79b4f0dc93e72
Source dataset
uspto-grants-2011_05
Patent number
US07943751B2

Reaction notes

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