Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → HCID 54033114, compound

HRID 377346Notes

Reaction equation

HRID 377346 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([CH2:8][CH:9]=O)[CH:5]=[CH:6][CH:7]=1.[C:11]([CH:16]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)([O:13][CH2:14][CH3:15])=[O:12]>C(Cl)Cl>[Br:1][C:2]1[CH:3]=[C:4]([CH2:8][CH:9]=[CH:16][C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH:5]=[CH:6][CH:7]=1

Participants

4

Reactant 2

HCID 70670Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl esterHCID 20387554(3-Bromophenyl)acetaldehyde

Product 1

HCID 54033114HCID 54033114, compound

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

60 g (246 mmol) of ethyl(3-bromophenyl)acetate (Compound B1) was converted into the title compound (oil) using 255 ml (255 mmol) of diisobutyl aluminum hydride (DIBAL-H, 1M in hexane), 85.8 g (250 mmol) of (carbethoxy methylene)triphenylphosphorane and 1.7 g of 10% Pd/C. The procedure was as follows: To a cold solution (-78° C.) of Compound B1 in CH2Cl2 was added dropwise (over a span of 1 hour) the diisobutyl aluminum hydride (DIBAL-H, 1M solution in hexane). After the DIBAL-H addition was complete, the reaction was stirred at -78 ° C. for an additional hour. The reaction was quenched by the dropwise addition of methanol, followed by water and 10% HCl. The mixture was then warmed to 0° C., stirred for 10 minutes and then washed with water, 10% aqueous NaHCO3 and brine. The organic phase was dried over MgSO4 and the solvent distilled off at ambient temperature to give crude (3-bromophenyl)acetaldehyde. To a cold solution (0° C.) of this crude aldehyde in CH2Cl2 was added a solution of the (carbethoxy methylene)triphenylphosphorane reagent in CH2Cl2. The mixture was stirred for 16 hours, concentrated in vacuo and purified by flash chromatography (silica, 10% EtOAc-hexane) to give ethyl 4-(3-bromophenyl)but-2-enoate as a mixture of E:Z isomers. This isomeric mixture was dissolved in EtOAc and hydrogenated over 10% Pd/C for 6 hours. The catalyst was filtered off and the filtrate concentrated in vacuo to give the title compound as a white solid.

Workup

  1. concentrationconcentrated in vacuo
  2. custompurified by flash chromatography (silica, 10% EtOAc-hexane)

Sources & evidence

ORD record
ord-001438a2486f468584e7c3558efc2344
Source dataset
uspto-grants-2000_02
Patent number
US06025388

Reaction notes

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