Uses
3-Trimethylsilylpropynal acts as an important organic intermediate. It is used in agrochemicals, pharmaceuticals and dyestuff field. Further, it is used in the preparation of [3-(trimethylsilyl)-2-propinyliden]-malononitrile.
Synthesis
Steps for the synthesis of 3-trimethylsilylpropynal:
1. A solution of trimethylsilylacetylene (5.0 mL, 36.10 mmol) in THF (25.0 mL) was added dropwise to a solution of EtMgBr in THF (1 M, 44.0 mL, 44.0 mmol) under nitrogen protection, and the reaction temperature was maintained at 10-150°C.
2. After the dropwise addition, the reaction mixture was stirred at room temperature for 1 hour.
3. A solution of Et2O (20.0 mL) in DMF (10.0 mL, 123.0 mmol) was slowly added to the reaction system at -25 °C, and the addition time was controlled to be within 30 min.
4. The resulting white suspension was gradually warmed to room temperature and stirring was continued for 1 hour.
5. The reaction mixture was heated to 30 °C and maintained for 15 minutes.
6. The reaction solution was cooled to 0 °C and poured into 5% H2SO4 solution.
7. The aqueous layer was separated and extracted three times with Et2O.
8. Combine the organic layers, wash with saturated aqueous NH4Cl solution and dry with anhydrous Na2SO4.
9. Concentrate under pressure to remove the solvent and obtain the crude product.
10. purification of the crude product by ball-to-ball distillation (20 mbar, room temperature) afforded 3-trimethylsilylpropynal (2.255 g, 49% yield).
Product characterization data:
1H NMR: δ 9.15 (s, 1H), 0.25 (s, 9H).
13C NMR: δ 176.7, 103.0, 102.3, 0.88.
References
[1] Tetrahedron Letters, 1995, vol. 36, # 3, p. 401 - 404
[2] Angewandte Chemie - International Edition, 2008, vol. 47, # 6, p. 1130 - 1133
[3] Tetrahedron, 2002, vol. 58, # 12, p. 2415 - 2422
[4] Arkivoc, 2012, vol. 2012, # 7, p. 253 - 273
[5] Patent: WO2009/141781, 2009, A1. Location in patent: Page/Page column 18
