Tetrahydrofuran → 3-Phosphino benzothiophene

HRID 10770Notes

Reaction equation

HRID 10770 reaction equation
[H-].[H-].[H-].[H-].[Li+].[Al+3].C1COCC1.Cl[P:13](Cl)[C:14]1[C:18]2[CH:19]=[CH:20][CH:21]=[CH:22][C:17]=2[S:16][CH:15]=1.[OH-].[Na+]>CCOCC>[PH2:13][C:14]1[C:18]2[CH:19]=[CH:20][CH:21]=[CH:22][C:17]=2[S:16][CH:15]=1

Participants

6

Reactant 4

HCID 8028TetrahydrofuranHCID 14798Sodium HydroxideHCID 115867083-Bis(chloro)phosphino benzo[d]thiopheneHCID 21226445Aluminium lithium hydride2×

Product 1

HCID 115356133-Phosphino benzothiophene

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent2×

Procedure

Under a nitrogen atmosphere a three necked 1 L flask was charged with diethyl ether (200 ml) and a solution of LiAlH4 in THF (58 mL of 1 N solution, 58 mmol). A solution of 3-bis(chloro)phosphino benzo[d]thiophene (18.24 g, 77.6 mmol) in ether (ca. 40 mL) was added dropwise over ca. 30 minutes. An exothermic reaction took place, and a solid formed. The excess LiAlH4 was hydrolyzed by the dropwise addition of NaOH (15 ml 4 N solution) which led to the formation of a colourless solid which precipitated readily. The supernatant was removed via cannula, and the solid was extracted with another 20 ml of ether. Evaporation of the solvent in vacuo left the crude phosphine as a mobile oil which was further purified by vacuum destillation. Yield: 11.31 g (87%), b.p. 93° C., 0.036 mbar. 1H-NMR (C6D6, 300 MHz) δ 3.59 (dd, 2H, 1JP.H=200.5 Hz, 4J=1.2 Hz, PH2); 7.10 (“tr.”, 1H, J=7.4 Hz, H-6); 7.19 (“dtr”, 2JH.P=7.5 Hz, 4J=1.2 Hz, H-2); 7.20 (tr, 1H, J=7.4 Hz, H-5); 7.57 (d, 1H, J=7.5 Hz, H-7); 7.70 (d, 1H, J=7.5 Hz, H-4). 13C-NMR (C6D6, 75 MHz) δ 122.06 (d, J=16.1 Hz, C-2); 122.693 (C-7); 123.72 (C-4); 124.60, 124.63 (C-5, C-6), 134.54 (d, J=35 Hz, C-2); 140.75 (d, J=2.6 Hz, C-8); 142.22 (d, J=2 Hz, C-9). 31P(1H)-NMR (C6D6, 121 MHz) δ-163.1.

Workup

  1. customAn exothermic reaction
  2. customa solid formed
  3. customprecipitated readily
  4. customThe supernatant was removed via cannula
  5. extractionthe solid was extracted with another 20 ml of ether
  6. customEvaporation of the solvent in vacuo
  7. waitleft the crude phosphine as a mobile oil which
  8. customwas further purified by vacuum destillation

Sources & evidence

ORD record
ord-1e075a27cd2c4e05b06018d53454909d
Source dataset
uspto-grants-2006_08
Patent number
US07094907B2

Reaction notes

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