Reaction #161648

Reaction equation

2-dicyclohexylphosphino-2′,4′,6′-tri-i-propyl-1,1′-biphenyl

tert-amyl alcohol

1-bromo-3,5-di-t-butyl benzene

lithium bis(trimethylsilyl) amide

benzophenone hydrazone

→

N-benzhydrylidene-N′-(3,5-di-tert-butyl-phenyl)-hydrazine

Solvents

ethylene glycol dimethyl ether

ethylene glycol dimethyl ether

Conditions

Workup

1. 1
   TemperatureThe mixture was heated
2. 2
   Otherto prepare a catalyst
3. 3
   OtherIn a separate reaction container under a nitrogen atmosphere
4. 4
   workup.ADDITIONThen, a solution containing the prepared catalyst
5. 5
   workup.ADDITIONwas added
6. 6
   TemperatureAfter deaeration, this was heated
7. 7
   workup.STIRRINGstirred at 90° C. for two hours under a nitrogen atmosphere
8. 8
   TemperatureThe reaction mixture was cooled to room temperature
9. 9
   Concentrationconcentrated under reduced pressure
10. 10
    OtherThe resulting residue was purified by silica gel column chromatography (hexane/ethyl acetate=100/5)

Procedure

Palladium acetate (8.4 mg, 0.037 mmol) and 2-dicyclohexylphosphino-2′,4′,6′-tri-i-propyl-1,1′-biphenyl (X-PHOS) (35.6 mg, 0.074 mmol) were dissolved in tert-amyl alcohol (10 μl, 0.093 mmol) and anhydrous ethylene glycol dimethyl ether (0.25 ml). The mixture was heated and stirred at 60° C. for five minutes under a nitrogen atmosphere to prepare a catalyst. In a separate reaction container under a nitrogen atmosphere, 1-bromo-3,5-di-t-butyl benzene (501 mg, 1.9 mmol), lithium bis(trimethylsilyl) amide (475 mg, 2.8 mmol), and benzophenone hydrazone (401 mg, 2.0 mmol) were dissolved in anhydrous ethylene glycol dimethyl ether (2.5 ml). Then, a solution containing the prepared catalyst was added thereto. After deaeration, this was heated and stirred at 90° C. for two hours under a nitrogen atmosphere. The reaction mixture was cooled to room temperature, and then concentrated under reduced pressure. The resulting residue was purified by silica gel column chromatography (hexane/ethyl acetate=100/5). Thus, N-benzhydrylidene-N′-(3,5-di-tert-butyl-phenyl)-hydrazine was obtained as a yellow amorphous material (699 mg, 97.7%).

Source