Lithium Hexamethyldisilazide → t-Butyl-[2-(4,8-dimethyl-non-1-enyl)-2,5,7,8-tetramethyl-chroman-6-yloxy]-dimethylsilane

HRID 1810598Notes

Reaction equation

HRID 1810598 reaction equation
Br[CH:2]([PH3+])[CH2:3][CH:4]([CH3:11])[CH2:5][CH2:6][CH2:7][CH:8]([CH3:10])[CH3:9].C[Si]([N-][Si](C)(C)C)(C)C.[Li+].[C:23]([Si:27]([CH3:46])([CH3:45])[O:28][C:29]1[C:30]([CH3:44])=[C:31]2[C:36](=[C:37]([CH3:40])[C:38]=1[CH3:39])[O:35][C:34]([CH3:43])([CH:41]=O)[CH2:33][CH2:32]2)([CH3:26])([CH3:25])[CH3:24]>C1COCC1>[C:23]([Si:27]([O:28][C:29]1[C:30]([CH3:44])=[C:31]2[C:36](=[C:37]([CH3:40])[C:38]=1[CH3:39])[O:35][C:34]([CH:41]=[CH:2][CH2:3][CH:4]([CH3:11])[CH2:5][CH2:6][CH2:7][CH:8]([CH3:10])[CH3:9])([CH3:43])[CH2:33][CH2:32]2)([CH3:46])[CH3:45])([CH3:24])([CH3:26])[CH3:25]

Participants

5

Reactant 3

HCID 2733832Lithium HexamethyldisilazideHCID 749761846-(t-Butyl-dimethyl-silyloxy)-2,5,7,8-tetramethyl-chroman-2-carbaldehydeHCID 866467961-Bromo-3,7-dimethyl octanyl phosphonium

Product 1

HCID 66752470t-Butyl-[2-(4,8-dimethyl-non-1-enyl)-2,5,7,8-tetramethyl-chroman-6-yloxy]-dimethylsilaneYield 80%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent3×

Conditions

Temperature
0 °C

Procedure

To a suspension of 1-bromo-3,7-dimethyl octanyl phosphonium (1.05 mmol) in 20 mL of anhydrous THF at 0° C. was added 1.05 mL of 1 M lithium bis(trimethysilyl)amide in THF. The mixture was stirred at 0° C. for 30 min, and compound iii (1 mmol) in 10 mL of THF was slowly added over a period of 1 h. After being stirred at room temperature for 1 h, the solution was concentrated, diluted with 20 mL of ethyl acetate, and washed, in tandem, with H2O and brine. The residue was purified by flash silica gel chromatography to afford t-butyl-[2-(4,8-dimethyl-non-1-enyl)-2,5,7,8-tetramethyl-chroman-6-yloxy]-dimethylsilane (iv) as colorless oil in 80% yield. 1H NMR (300 MHz, CDCl3) δ 0.11 (s, 6H), 0.86-0.95 (m, 6H), 1.04 (s, 9H), 1.39 (s, 1H), 1.49-1.56 (m, 1H), 1.76-1.86 (m, 1H), 2.01-2.06 (m, 2H), 2.11 (s, 3H), 2.17 (s, 6H), 2.25-2.32 (m, 1H), 2.62 (t, J=6.60 Hz, 2H), 5.30-5.44 (m, 2H).

Workup

  1. stirringAfter being stirred at room temperature for 1 h
  2. concentrationthe solution was concentrated
  3. additiondiluted with 20 mL of ethyl acetate
  4. washwashed, in tandem, with H2O and brine
  5. customThe residue was purified by flash silica gel chromatography

Sources & evidence

ORD record
ord-d9009274bb274d37825afc5d16d0bffc
Source dataset
uspto-grants-2013_01
Patent number
US08362071B2

Reaction notes

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