2,4-Dichlorobenzaldehyde → 5-(2,4-Dichlorophenyl)-3-methylpenta-2,4-dienoic acid ethyl ester

HRID 597892Notes

Reaction equation

[CH3:1][CH2:2][O:3][C:4](/[CH:6]=[C:7](/[CH2:9]P(OCC)(OCC)=O)\[CH3:8])=[O:5].[Li]CCCC.[Cl:23][C:24]1[CH:31]=[C:30]([Cl:32])[CH:29]=[CH:28][C:25]=1[CH:26]=O>C1COCC1.CN1C(=O)N(C)CCC1>[CH2:2]([O:3][C:4](=[O:5])[CH:6]=[C:7]([CH3:8])[CH:9]=[CH:26][C:25]1[CH:28]=[CH:29][C:30]([Cl:32])=[CH:31][C:24]=1[Cl:23])[CH3:1]

Participants

Conditions

Temperature: -78 °C

Procedure

Triethyl 3-methyl-4-phosphonocrotonate (34.24 g, 0.129 mol, 1.3 eq) was dissolved in THF/DMPU (100 mL/200 mL) and the mixture was cooled to −78° C. BuLi (51.8 mL of a 2.5M solution in hexanes, 1.3 eq) was added dropwise. The mixture was stirred for 20 min and then a solution of 2,4-dichlorobenzaldehyde (17.6 g, 0.1 mol) in THF/DMPU (20 mL/40 mL) was added dropwise. The resulting mixture was stirred for 1 hour and then allowed to warm to room temperature. NH4Cl(sat) was added and the mixture extracted with EtOAc. The organic layers were washed with, water, brine, and dried (MgSO4). Removal of solvent under reduced pressure followed by silica gel chromatography (0-1-2-3% EtOAc in hexanes) gave 23.3 g of 5-(2,4-dichlorophenyl)-3-methylpenta-2,4-dienoic acid ethyl ester.

Workup

stirringThe resulting mixture was stirred for 1 hour
temperatureto warm to room temperature
extractionthe mixture extracted with EtOAc
washThe organic layers were washed with, water, brine
dry with materialdried (MgSO4)
customRemoval of solvent under reduced pressure

Sources & evidence

ORD record: ord-8cfcef87f2424c0a874d5aa1e823a53c
Source dataset: uspto-grants-2011_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07897601B2

Reaction notes

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