(Triphenylphosphoranylidene)acetaldehyde → 3-(4-Bromo-2-prop-2-ynyloxy-phenyl)-propenal

HRID 870890Notes

Reaction equation

HRID 870890 reaction equation
[Br:1][C:2]1[CH:9]=[CH:8][C:5]([CH:6]=O)=[C:4]([O:10][CH2:11][C:12]#[CH:13])[CH:3]=1.[CH:14]([CH:16]=P(C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)=[O:15]>C1COCC1>[Br:1][C:2]1[CH:9]=[CH:8][C:5](/[CH:6]=[CH:16]/[CH:14]=[O:15])=[C:4]([O:10][CH2:11][C:12]#[CH:13])[CH:3]=1

Participants

4

Reactant 2

HCID 75051(Triphenylphosphoranylidene)acetaldehydeHCID 866958854-Bromo-2-(prop-2-ynyloxy)benzaldehyde

Product 1

HCID 866958863-(4-Bromo-2-prop-2-ynyloxy-phenyl)-propenalYield 73%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A mixture of 4-bromo-2-(prop-2-ynyloxy)benzaldehyde (0.852 g, 3.56 mmol) and formylmethylenetriphenylphosphorane (2.2 g, 7.12 mmol, 2 equiv) suspended in THF (20 mL) under nitrogen was stirred at ambient temperature for 18 h and then at 50° C. for another 24 h. The reaction mixture was filtered through a bed of silica gel (˜25 g) eluting with EtOAc:hexane (1:4, 300 mL). The filtrate was concentrated under reduced pressure and the residue was purified by silica gel chromatography using a linear gradient of EtOAc:hexane (1:19 to 1:9). Pooled fractions containing the title compound and its Z-isomer in the ratio of (39:11, by NMR) was concentrated under reduced pressure to give (E)-3-(4-bromo-2-(prop-2-ynyloxy)phenyl)acrylaldehyde (0.69 g, 2.6 mmol, 57% yield). 1H NMR (500 MHz, CDCl3) δ 9.71 (d, J=7.6 Hz, 1H), 7.77 (d, J=16.2 Hz, 1H), 7.45 (d, J=8.2 Hz, 1H), 7.26-7.17 (m, 2H), 6.77 (dd, J=16.2, 7.6 Hz, 1H), 4.82 (d, J=2.4 Hz, 1H), 4.80-4.75 (m, 1H), 2.62 (t, J=2.4 Hz, 1H). The Z-isomer showed the aldehydic proton at δ 9.87 (d, J=7.9 Hz) and a smaller cis-coupling (J=11.4 Hz) for the olefinic proton at δ 6.22; LCMS (Method B) (ESI) m/e 265.0, 267.0 Br pattern [(M+H)+, calcd for C12H9BrO2 265.0].

Workup

  1. waitat 50° C. for another 24 h
  2. filtrationThe reaction mixture was filtered through a bed of silica gel (˜25 g)
  3. washeluting with EtOAc:hexane (1:4, 300 mL)
  4. concentrationThe filtrate was concentrated under reduced pressure
  5. customthe residue was purified by silica gel chromatography
  6. additionPooled fractions containing the title compound and its Z-isomer in the ratio of (39:11, by NMR)
  7. concentrationwas concentrated under reduced pressure

Sources & evidence

ORD record
ord-126e56905baa4415a3abda2ad57e7d0f
Source dataset
uspto-grants-2015_03
Patent number
US08969564B2

Reaction notes

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