Triphenyl(3,4,5-trimethoxybenzyl)phosphonium bromide → 4-Bromo-6-[(Z)-2-(3,4,5-trimethoxyphenyl)vinyl]-1,2-di(tert-butyldimethylsilyloxy)benzene

HRID 218251Notes

Reaction equation

HRID 218251 reaction equation
[Br-].[CH3:2][O:3][C:4]1[CH:5]=[C:6]([CH:27]=[C:28]([O:32][CH3:33])[C:29]=1[O:30][CH3:31])[CH2:7][P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C([Li])CCC.[Si:39]([O:46][C:47]1[C:54]([O:55][Si:56]([C:59]([CH3:62])([CH3:61])[CH3:60])([CH3:58])[CH3:57])=[CH:53][C:52]([Br:63])=[CH:51][C:48]=1[CH:49]=O)([C:42]([CH3:45])([CH3:44])[CH3:43])([CH3:41])[CH3:40]>O1CCCC1.CCCCCC.C(OC)(C)(C)C>[Br:63][C:52]1[CH:51]=[C:48](/[CH:49]=[CH:7]\[C:6]2[CH:27]=[C:28]([O:32][CH3:33])[C:29]([O:30][CH3:31])=[C:4]([O:3][CH3:2])[CH:5]=2)[C:47]([O:46][Si:39]([C:42]([CH3:45])([CH3:43])[CH3:44])([CH3:41])[CH3:40])=[C:54]([O:55][Si:56]([C:59]([CH3:62])([CH3:61])[CH3:60])([CH3:57])[CH3:58])[CH:53]=1

Participants

7

Reactant 3

HCID 370917Triphenyl(3,4,5-trimethoxybenzyl)phosphonium bromideHCID 601306802,3-Di(tert-butyldimethylsilyloxy)-5-bromo benzaldehydeHCID 178418339Butyllithium

Product 1

HCID 601306724-Bromo-6-[(Z)-2-(3,4,5-trimethoxyphenyl)vinyl]-1,2-di(tert-butyldimethylsilyloxy)benzeneYield 55.9%

Reagents, catalysts & solvents 3

HCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolventHCID 15413tert-Butyl methyl etherSolvent

Conditions

Temperature
0 °C

Procedure

A suspension of 3,4,5-trimethoxybenzyltriphenylphosphonium bromide (1.69 g, 3.23 mmol) in tetrahydrofuran (30 mL) was cooled to 0° C. and butyllithium (2 mL of a 1.6 N solution in hexane, 3.23 mmol) was added dropwise. The brick red solution was stirred at 0° C. for 20 min, then a solution of 19 (0.96 g, ca 2.2 mmol) in tetrahydrofuran (12 mL) was added dropwise. The temperature was allowed to rise to room temperature overnight, than the reaction was diluted with tert-butylmethyl ether (ca 100 mL) and washed with water (ca 50 mL, containing 1 mL 2N HCl) then brine (30 mL). The organic layer was dried over sodium sulphate and the solvent removed under reduced pressure to give a crude which was purified by column (elution with cyclohexane:AcOEt 10:1) to give 0.75 g of 20 still impure with 20% of the E isomer.

Workup

  1. waitto rise to room temperature overnight, than the reaction
  2. washwashed with water (ca 50 mL, containing 1 mL 2N HCl)
  3. dry with materialThe organic layer was dried over sodium sulphate
  4. customthe solvent removed under reduced pressure
  5. customto give a crude which
  6. customwas purified by column (elution with cyclohexane:AcOEt 10:1)

Sources & evidence

ORD record
ord-ae5a82024ead43189050401038470273
Source dataset
uspto-grants-2012_06
Patent number
US08198302B2

Reaction notes

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