Ethoxy trimethylsilyl acetylene

InChl = lS/C7H140Si/cl-5-8-6-7-9(2,3)4/h5H2,l-4H3 InChIKey = FKMCADCEOYUAFV-UHFFFAOYSA-N 

Solubility insol H2O freely sol most common solvents. 

Form Supplied in colorless liquid widely available. Preparative Methods by silylation of ethoxyacetylene. Handling, Storage, and Precautions storable in a refrigerator for years without any polymerization or decomposition (one of the features that favors the use of this reagent over ethoxyacetylene for many applications). 

Dehydrative Condensation of Carboxylic Acids with Amines and Alcohols. In the presence of a mercuric catalyst, (1) causes dehydrative condensation of carboxylic acids with H-acidic materials such as amines and alcohols to give the corresponding amides, esters, lactones, and peptides in high yields.  

120 °C is a convenient method for preparation of trimethyl-silylketene (6) (eq 2). This ketene is an easy-handling, storable, and distillable monomeric liquid, and is useful for acylation of sterically hindered alcohols and amines (eq 3). Other useful applications of (6) are represented in the preparation of a-silyl acetates, a-silyl ketones, Q ,/3-unsaturated esters, and silylallenes.  

---

Ethoxy(trimethylsilyl)acetylene, (CHjXiSiC COCjHj (1). The reagent is prepared by... 

DliHYDRATION Dimethylformamide-Thionyl chloride. Ethoxy(trimethylsilyl)acetylene. Potassium hydride. 

Carboxylic anhydrides Ethoxy(trimethylsilyl)acetylene. Sulfene. 

The application of ethoxy(trimethylsilyl)acetylene as a dehydrating agent was also extended to polyanhydride synthesis (eq 5). In contrast to traditional methods, this was carried out at low temperature (20 0 °C) by the electrophilic addition-elimination reaction of ethoxy(trimethylsilyl)acetylene, avoiding decomposition due to heating of sensitive monomers and polymers. ... 

Dehydrative Condensation of Carboxylic Acids with Amines and Alcohols. For reversible fluorescent labeling of amino groups, ethoxy(trimethylsilyl)acetylene was used as a dehydrating reagent to couple dansylaminomethylmaleic acid (DAM) with benzylamine through a maleic anhydride intermediate (eq 6). ... 

Preparation of TVimethylsilylketene. The convenient preparation of trimethylsUylketene by thermolysis of ethoxy-(trimethylsilyl)acetylene at 120 °C (eq 7) has been studied by means of ab initio and semiempitical computations. ... 

Ethoxy(trimethylsilyl)acetylene reacted by a [2 + 2 + 2] cycloaddition with diyne 11 in the presence of 10 mol% Rh(cod)2-BF4 and 10 mol% rac-BlNAP in dichloromethane (0.021 M) at ambient temperature to give aryl ether derivative 12 in 50% yield, thus providing a valuable synthetic route to highly substituted benzene derivatives (eq 9). ... 

Electron-rich alkynes, including ethoxy(trimethylsilyl)-acetylene, reacted with chromium alkenylcarbene conplexes at — 10°C in acetonitrile in the presence of a stoichiometric amount of Ni(cod)2 with warming to 20 °C over 2 h to afford moderate yields (40-49%) of cyclopentenones (eq 10). This completely stereoselective nickel(0)-mediated [3 + 2] cyclization reaction of chromium alkenyl(methoxy)carbene complexes with both electron-withdrawing and electron-donating substituted alkynes provides a general synthesis of substituted 2-cyclo-pentenone derivatives, important synthons for the construction of more complex molecules. ... 

Oxidations. Aikynes of high nucleophilicity such as ethoxy-(trimethylsilyl)acetylene react with electrophilic O3 to give vicinal dicarbonyl derivatives. In contrast to alkylated or ary-lated acetylenes, neither products of complete C-C cleavage nor peroxidic materials were detected as primary products. Ethoxy-(trimethylsilyl)acetylene reacted with ozone to yield a mixture of ethyl 2-oxo-2-(trimethyl)acetate (13) and ethyl trimethylsUyl oxalate (14) (eq 11). The mechanism of this reaction was also discussed. ... 

Preparative Methods most often prepared (eq 1) by pyrolysis of ethoxy(trimethylsilyl)acetylene at 120 °C (100 mmol scale, 65% yield). Recently, pyrolysis of t-butoxy(trimethylsilyl) acetylene has been shown to be a convenient alternative for the preparation of trimethylsilylketene (1). Thermal decomposition of t-butoxy(trimethylsilyl)acetylene causes elimination of 2-methylpropene slowly at temperatures as low as 50 °C and instantaneously at 100-110 °C (30 mmol scale, 63% yield). The main advantage of this method is that it is possible to generate trimethylsilylketene in the presence of nucleophiles, leading to in situ trimethylsilylacetylation (eq 2). Increased shielding of the triple bond prevents problems such as polymerization and nucleophilic attack that occur when the ketene is generated in situ from (trimethylsilyl)ethoxyacetylene. Trimethylsilylketene can also be prepared (eq 3) via the dehydration of commercially available trimethylsilylacetic acid with 1,3-dicyclohexylcarbodiimide (DCC) in the presence of a catalytic amount of triethylamine (100 mmol scale, 63%). Other typical methods used for ketene generation such as dehy-drohalogenation of the acyl chloride and pyrolysis of the... 

---