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

HRID 218250Notes

Reaction equation

HRID 218250 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])=[C:53]([CH3:63])[CH:52]=[CH:51][C:48]=1[CH:49]=O)([C:42]([CH3:45])([CH3:44])[CH3:43])([CH3:41])[CH3:40]>O1CCCC1.CCCCCC.[Cl-].[Na+].O>[CH3:63][C:53]1[C:54]([O:55][Si:56]([C:59]([CH3:62])([CH3:61])[CH3:60])([CH3:58])[CH3:57])=[C:47]([O:46][Si:39]([C:42]([CH3:45])([CH3:44])[CH3:43])([CH3:40])[CH3:41])[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)=[CH:51][CH:52]=1

Participants

7

Reactant 3

HCID 370917Triphenyl(3,4,5-trimethoxybenzyl)phosphonium bromideHCID 877685842,3-Bis-tert-butyldimethylsilyloxy-4-methylbenzaldehydeHCID 178418339Butyllithium

Product 1

HCID 601306753-Methyl-6-[(z)-2-(3,4,5-trimethoxyphenyl)vinyl]-1,2-di(tert-butyldimethylsilyloxy)benzeneYield 48.7%

Reagents, catalysts & solvents 3

HCID 8028TetrahydrofuranSolvent2×HCID 8058HexaneSolventHCID 57417360Sodium chloride; waterSolvent

Conditions

Temperature
0 °C

Procedure

A suspension of 3,4,5-trimethoxybenzyltriphenylphosphonium bromide (1.77 g, 3.4 mmol) in tetrahydrofuran (40 mL) was cooled to 0° C. and butyllithium (2.1 mL of a 1.6 N solution in hexane, 3.39 mmol) was added dropwise. The brick red solution was stirred at 0° C. for 20 min, then cooled to −78° C. and a solution of 16 (0.86 g, 2.26 mmol) in tetrahydrofuran (15 mL) was added dropwise. The temperature was allowed to rise to room temperature overnight, than the reaction was poured into brine (100 mL, containing 5 mL of 1 n HCl) and extracted twice with tert-butylmethyl ether (ca 100+50 mL). The combined organic extracts were washed with brine, dried over sodium sulphate and the solvent removed under reduced pressure to give a crude which was purified by column (cyclohexane:AcOEt 9:1) to give 0.6 g of 17:

Workup

  1. temperaturecooled to −78° C.
  2. waitto rise to room temperature overnight, than the reaction
  3. extractionextracted twice with tert-butylmethyl ether (ca 100+50 mL)
  4. washThe combined organic extracts were washed with brine
  5. dry with materialdried over sodium sulphate
  6. customthe solvent removed under reduced pressure
  7. customto give a crude which
  8. customwas purified by column (cyclohexane:AcOEt 9:1)

Sources & evidence

ORD record
ord-18e381c1bb114dd0aeaf98be7402d914
Source dataset
uspto-grants-2012_06
Patent number
US08198302B2

Reaction notes

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