Formula C8H18Si2 | Density 791 kg/m³ Appearance Colorless to white Liquid | |
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Bis(trimethylsilyl)acetylene (BTMSA) is an organosilicon compound with the formula C2(Si(CH3)3)2. 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:
Li2C2 + 2 (CH3)3SiCl → [(CH3)3Si]2C2 + 2 LiClApplications
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. 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.
Cp2TiCl2 + Mg + Me3SiC≡CSiMe3 → Cp2Ti[(CSiMe3)2] + MgCl2BTMSA is also used in the total synthesis of epibatidine (and analogs), and also in the synthesis of iclaprim.