Chemistry:Bis(trimethylsilyl)acetylene
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| Names | |
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| Preferred IUPAC name
Ethynediylbis(trimethylsilane) | |
| Other names
BTMSA
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
PubChem CID
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| Properties | |
| C8H18Si2 | |
| Molar mass | 170.402 g·mol−1 |
| Appearance | Colorless to white Liquid |
| Density | 0.791 g/cm3 |
| Melting point | 26 °C (79 °F; 299 K) |
| Boiling point | 134.6 ± 8.0 °C |
| 0.031 g/L | |
| Hazards | |
| Main hazards | Flammable, Irritant |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
 verify (what is   ?)
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| Infobox references | |
Bis(trimethylsilyl)acetylene (BTMSA) is an organosilicon compound with the formula Me3SiC≡CSiMe3 (Me = methyl). It is a colorless liquid that is soluble in organic solvents. This compound is used as a surrogate for acetylene.
BTMSA is prepared by treating acetylene with butyl lithium followed by addition of chlorotrimethylsilane:[1]
- Li2C2 + 2 Me3SiCl → Me3SiC≡CSiMe3 + 2 LiCl
Applications
BTMSA is used as a nucleophile in Friedel-Crafts type acylations and alkylations and a precursor to lithium trimethylsilylacetylide. The TMS groups can be removed with tetra-n-butylammonium fluoride (TBAF) and replaced with protons. BTMSA is also a useful reagent in cycloaddition reactions. Illustrating its versatility, BTMSA was used in a concise total synthesis of (±)-estrone.[2] A key step in this synthesis was the formation of the steroidal skeleton, catalyzed by CpCo(CO)2.
BTMSA also serves as a ligand in organometallic chemistry. For example, it forms stable adducts with metallocenes.[3]
- Cp2TiCl2 + Mg + Me3SiC≡CSiMe3 → Cp2Ti[(CSiMe3)2] + MgCl2
BTMSA is also used in the total synthesis of epibatidine (and analogs), and also in the synthesis of iclaprim.
References
- ↑ Walton, D.R.M.; Waugh, F. (1972). "Friedel-crafts reactions of bis(trimethylsilyl)polyynes with acyl chlorides; a useful route to terminal-alkynyl ketones". Journal of Organometallic Chemistry 37: 45–56. doi:10.1016/S0022-328X(00)89260-8.
- ↑ Curtin, Michael L.; Wang, Cheng (2008). "Bis(trimethylsilyl)acetylene". Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rb209.pub2. ISBN 978-0471936237.
- ↑ Rosenthal, Uwe; Burlakov, Vladimir V.; Arndt, Perdita; Baumann, Wolfgang; Spannenberg, Anke (2003). "The Titanocene Complex of Bis(trimethylsilyl)acetylene: Synthesis, Structure, and Chemistry†". Organometallics 22 (5): 884–900. doi:10.1021/om0208570.
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