Tetrahydrofuran → Dimethyl titanocene

HRID 1370240Notes

Reaction equation

HRID 1370240 reaction equation
[Cl-].[Cl-].[CH-:3]1[CH:7]=[CH:6][CH:5]=[CH:4]1.[CH-:8]1[CH:12]=[CH:11][CH:10]=[CH:9]1.[Ti+2:13].[CH3:14][Mg]Cl.C1COCC1>C1(C)C=CC=CC=1>[CH3:8][C-:3]1[CH:7]=[CH:6][CH:5]=[CH:4]1.[C-:8]1([CH3:14])[CH:12]=[CH:11][CH:10]=[CH:9]1.[Ti+2:13]

Participants

6

Reactant 4

HCID 8028TetrahydrofuranHCID 6917972HCID 6917972, compound3×HCID 124040768Titanocene dichiorideHCID 178418332HCID 178418332, compound

Product 1

HCID 129651941Dimethyl titanocene

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
2.5 °C

Procedure

To a well stirred slurry of titanocene dichloride (Cp2TiCl2) (249 g, 1.00 mol) in toluene (2.75 L) chilled to −5° C. (internal temp) was added methyl magnesium chloride (CH3MgCl) (750 mL, 3.0M in THF, 2.25 mol) over 1 h, maintaining the temperature below 8° C. The resulting orange slurry is aged at 0-5° C. for 1 h, or until the insoluble purple Cp2TiCl2 has dissolved. A NMR was taken to confirm reaction completion (see below), then the reaction was quenched into a solution of 6% aqueous ammonium chloride (700 mL), maintained at 0-5° C. The layers were separated and the organic phase was washed with cold water (3×575 mL) and brine (575 mL), then was dried with Na2SO4 (220 g). The filtered organic layer was evaporated to 1.5 Kg (maintaining an internal temperature of 25° or less). Weight % assay by 1H NMR showed the solution to contain 187 g product (90%, 12.5 wt % solution in toluene/THF). Typically, the material was greater than 95% pure, with only traces of the starting material and monomethyl intermediate. The solution may be further concentrated to 1.0 Kg, giving a 18 wt % solution in toluene, allowing for an easier assay. However, the presence of a small amount of THF increases the stability of the compound. The material was stored under nitrogen in a sealed carboy at 0° C. 1H NMR Cp2Ti(CH3)2: δ6.05 (s, 10H), −0.05 (s, 6H). Cp2TiCl(CH3): δ6.22 (s, 10H), 0.80 (s, 3H). Cp2TiCl2: δ6.56 (s, 10H). 13C NMR Cp2Ti(CH3)2: δ113.20 (Cp2), 45.77 ((CH3)2). Cp2TiClCH3: δ115.86 (Cp2), 50.37 (CH3). Cp2TiCl2: δ120.18.

Workup

  1. temperaturemaintaining the temperature below 8° C
  2. customreaction completion (see below)
  3. customthe reaction was quenched into a solution of 6% aqueous ammonium chloride (700 mL)
  4. customThe layers were separated
  5. washthe organic phase was washed with cold water (3×575 mL) and brine (575 mL)
  6. dry with materialwas dried with Na2SO4 (220 g)
  7. customThe filtered organic layer was evaporated to 1.5 Kg (
  8. temperaturemaintaining an internal temperature of 25° or less)
  9. concentrationThe solution may be further concentrated to 1.0 Kg
  10. customgiving a 18 wt % solution in toluene
  11. customwas stored under nitrogen in a sealed carboy at 0° C

Sources & evidence

ORD record
ord-e66ed0538f984a258813b52a69f96187
Source dataset
uspto-grants-2003_06
Patent number
US06583142B2

Reaction notes

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