Description
Triethylsilane is a useful versatile reductant since it has a active hydride. It can be used for mediated the palladium-catalyzed dehalogenation reaction of alkyl or aryl halides, the reduction of primary, secondary, and tertiary chlorides, bromides, and iodides catalyzed by iridium, as well as efficient reduction of multiple bonds, azides, imines, and nitro groups, as well as benzyl group and allyl group deprotection. It is also specifically for the hydrosilation of olefins to give alkyl silanes. It is also the catalyst for synthesis of a spiro-oxindole blocker of Nav1.7 for the treatment of pain, redox initiated cationic polymerization and Beckmann rearrangement of cyclododecanone oxime as well as regioselective reductive coupling of enones and allenes.
Chemical Properties
Clear liquid
Uses
Triethylsilane serves as an exemplar for organosilicon hydride behavior as a mild reducing agent. It is frequently
chosen as a synthetic reagent because of its availability, convenient
physical properties, and economy relative to other organosilicon
hydrides which might otherwise be suitable for effecting specific
chemical transformations.
This reagent is generally used in these reactions: Hydrosilylations, Silane Alcoholysis, Formation of Singlet Oxygen, Reduction of Acyl Derivatives to Aldehydes, Radical Chain Reductions, Ionic Hydrogenations and Reductive Substitutions(The
polar nature of the Si–H bond enables triethylsilane to act as a
hydride donor to electron-deficient centers.), Reductive Etherifications and Acetal Reductions, Ether Cleavages, Reductive Couplings and Cyclizations, Aromatic Silylations, Generation of Other Triethylsilyl Reagents, etc.
Related Reagents: Phenylsilane–cesium fluoride;
tri-n-butylstannane; tricarbonylchloroiridium–diethyl(methyl)
silane–carbon monoxide; triethylsilane–trifluoroacetic acid.
Uses
Triethylsilane is a trialkylsilicon hydride used in the synthesis of alkylsilanes via hydrosilation of olefins. It acts as a reducing agent in the reduction of 2-chromanols, since it has an active hydride. It acts as a catalyst for redox initiated cationic polymerization, regioselective reductive coupling of enones and allenes, and Beckmann rearrangement of cyclododecanone oxime. It is associated with trifluoroacetic acid and involved in the selective reduction of alkenes.
Definition
ChEBI: Triethylsilane is an organosilicon compound. It has a role as a reducing agent.
Application
Triethylsilane is used as a reducing agent inmany organic synthetic reactions.
Used to reduce metal salts. Enhances deprotection of t-butoxycarbonyl-protected amines and tert-butylesters.
Used in the reductive amidation of oxazolidinones with amino acids to provide dipeptides.
Converts aldehydes to symmetrical and unsymmetrical ethers.
Used in the "in-situ" preparation of diborane and haloboranes.
Production Methods
A synthetic method of triethylsilane comprises the following steps: reacting sodium hydride with trimethyl borate to prepare trimethoxy sodium borohydride; adding triethylchlorosilane to trimethoxy sodium monohydroborate to react to obtain triethylsilane.
To a 500ml reaction flask, 20g (0.5mol) of 60% sodium hydride and 80g of anhydrous tetrahydrofuran were added. Stirring and cooling to 0-10 ℃ under the protection of nitrogen, the mixture was then maintained under nitrogen protection, stirred, and the liquid temperature at 0-10 ℃, and dropwise added 57.2g (0.55mol) of trimethyl borate. After the dropwise addition, the temperature was kept at 0-10 ℃ and stirred for 1 hour.Maintaining the nitrogen protection, stirring and liquid temperature of the reaction liquid at 0-10 ℃, and then dropwise adding 67.7g (0.45mol) of triethylchlorosilane. After the dropwise addition, continuously keep the temperature at 0-10 ℃ and stir for 1 hour. The reaction solution was then filtered at room temperature. Rectifying the filtrate at normal pressure and collecting fractions with the boiling range of 109-110 ℃ as triethylsilane to obtain 46.1g of triethylsilane, which yields 88.2%. 45-64 ℃: a mixed solution of trimethyl borate and tetrahydrofuran; 64-109 ℃:a mixture of tetrahydrofuran and a small triethylsilane.
Fire Hazard
Highly flammable; flash point －4°C (25°F)
(Aldrich 1996).
It does not ignite spontaneously in air,
but it can explode on heating. The ease
of oxidation of this compound is relatively
lower than mono- and dialkylsilanes. Reaction
with oxidizing substances, however,
can be violent. Reaction with boron trichloride
could be explosive at room temperature.
Even at 78°C ( 108°F), mixing these
reagents caused pressure buildup and combustion
(Matteson 1990).
Flammability and Explosibility
Flammable
Purification Methods
Reflux triethylsilane over molecular sieves, then distil it. It is passed through neutral alumina before use [Randolph & Wrighton J Am Chem Soc 108 3366 1986]. [Beilstein 4 IV 3895.]
Precautions
Triethylsilane is a flammable, but not pyrophoric, liquid. As with all organosilicon hydrides, it is capable of releasing hydrogen gas upon storage, particularly in the presence of acids, bases, or fluoride-releasing salts. Proper precautions should be taken to vent possible hydrogen buildup when opening vessels in which triethylsilane is stored.
References
R. Boukherroub,?,?, C. Chatgilialoglu,,§ and, and G. Manuel?. "PdCl2-Catalyzed Reduction of Organic Halides by Triethylsilane." Organometallics 15.5(1996):1508-1510.
Jian Yang and, and M. Brookhart. "Iridium-Catalyzed Reduction of Alkyl Halides by Triethylsilane." Journal of the American Chemical Society 129.42(2007):12656-7.
And, Pijus K. Mandal, and J. S. Mcmurray. "Pd?C-Induced Catalytic Transfer Hydrogenation with Triethylsilane." Journal of Organic Chemistry 72.17(2007):6599-6601.
Chen, Bang Chi, et al. "Novel triethylsilane mediated reductive N -alkylation of amines: improved synthesis of 1-(4-imidazolyl)methyl-4-sulfonylbenzodiazepines, new farnesyltransferase inhibitors." Tetrahedron Letters 42.7(2001):1245-1246.
