Reacción #6637

Ecuación de reacción

2,2,4,4-tetramethyl-6-bromothiochroman

Compound 72

2,2,4,4-tetramethyl-6-bromothiochroman

trimethylsilylacetylene

trimethylsilylacetylene

→

title compound

2,2,4,4-Tetramethyl-6-trimethylsilylethynyl-thiochroman

Disolventes

triethylamine

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrodegassed
2. 2
   OtroThe reaction mixture was degassed again
3. 3
   Otrothe tube was sealed
4. 4
   Temperaturato cool to room temperature
5. 5
   OtroThe mixture was then degassed
6. 6
   Temperaturaheated in the sealed tube at 100 degrees C
7. 7
   workup.WAITfor 96 h
8. 8
   TemperaturaThe mixture was cooled to room temperature
9. 9
   Extracciónextracted with 3×10 ml of ether
10. 10
    Lavadowashed successively with 25 ml of water and 25 ml of saturated sodium chloride solution
11. 11
    Secadodried (MgSO4) The solvent
12. 12
    Otrowas removed in vacuo
13. 13
    Otrothe residue purified by flash chromatography (silica; hexanes followed by 3% ethyl acetate in hexanes)

Procedimiento

A solution of 600 mg (2.11 mmol) of 2,2,4,4-tetramethyl-6-bromothiochroman (Compound 72) in 1.5 ml of triethylamine was placed in a heavy-walled tube and degassed and then treated under argon with 1.4 g (14.3 mmol) of trimethylsilylacetylene and a powdered mixture of 75 mg (0.39 mmol) of cuprous iodide and 150 mg (0.21 mmol) of bis(triphenylphosphine) palladium (II) chloride. The reaction mixture was degassed again, then placed under argon and the tube was sealed. The mixture was heated at 100 degrees C. for 24 h, allowed to cool to room temperature and then treated with a further 1.4 g (14.3 mmol) of trimethylsilylacetylene and a powdered mixture of 75 mg (0.39 mmol) of cuprous iodide and 150 mg (0.21 mmol) of bis(triphenylphosphine) palladium (II) chloride. The mixture was then degassed, placed under argon and then heated in the sealed tube at 100 degrees C. for 96 h. The mixture was cooled to room temperature and extracted with 3×10 ml of ether. The organic extracts were combined, washed successively with 25 ml of water and 25 ml of saturated sodium chloride solution and then dried (MgSO4) The solvent was removed in vacuo and the residue purified by flash chromatography (silica; hexanes followed by 3% ethyl acetate in hexanes) to give the title compound as a yellow, crystalline solid. PMR (CDCl3): δ 0.23 (9H, s), 1.36 (6H, s), 1.39 (6H, s), 1.94 (2H, s), 7.17 (1H, dd, J~8.2 Hz, 1.8 Hz), 7.25 (1H, d, J~1.8 Hz), 7.30 (1H, d, J~8.2 Hz). MS exact mass, m/l 302.1519 (calcd. for C18H26S Si, 382.1524).

Fuente