Chlorotriethylsilane is used in laboratory chemicals. It is used for preparing silylating agent and acts as a catalyst for lewis acid. It is used for executing chemical reactions for silicon oil. Its conformations, structures, and vibrational spectra are studied. It also participates in nickel - catalyzed reductive conjugate addition to enones.

Synthesis of chlorotriethylsilane

A reflux condenser, a thermometer and a stirrer are attached to a 500 mL four-necked glass flask, and the inside is installed. Was replaced with nitrogen. In this flask, 211.5 g (1.0 mol) of phenyltrichlorosilane ) And 5.9 g (0.02 mol) of tetrabutylphosphonium chloride. Internal temperature 69.0 g (0.6 mol) of triethylsilane for 2 hours while adjusting the temperature to 100-120 ° C. After hanging and dropping, it was aged at the same temperature for 1 hour. Internal temperature of the obtained reaction solution under reduced pressure The reaction mixture was allowed to flow out and separated from the catalyst while adjusting so that the temperature did not exceed 90 ° C. Gain By rectifying the obtained fraction, 90.3 g of phenyldichlorosilane (0.508 mo) Yield 84.7% with respect to triethylsilane) and 88.2 g of chlorotriethylsilane (0.585 mol, yield 97.5% based on triethylsilane) was obtained.[1]

Conformations, Structures, and Vibrational Spectra of chlorotriethylsilane

Organohalosilanes are an important family of compounds with a wide range of applications in organic and organometallic synthesis.  For instance, alkylhalosilanes are important precursors of alkylsilanols, which are well-known intermediates in industrially important sol?gel processes using organometallic compounds. 2 Following a series of previous studies dealing with the molecular structures and vibrational spectra of a number of trimethylsilane derivatives,  we carry out a joint theoretical and experimental study of the molecular structures and vibrational spectra of two related triethylsilylhalo derivatives, namely chlorotriethylsilane (TECS) and triethylbromosilane (TEBS). Few works in the literature deal with the vibrational spectra of the title molecules. In those that do, both TECS and TEBS are treated as symmetric top rotators belonging to the C3v symmetry group. From a structural point of view, there is only one previous work in which Volkov et al. report the microwave spectrum of triethylchlorosilane. The success of a refinement can also be quantified from the value of the goodness-of-fit function, RG. For both TECS and TEBS, these values are low:? 0.043 for TECS and 0.044 for TEBS. For TECS, the best fit relates to a composition of 57% conformer II and 43% conformer IV. For TEBS, these compositions were 33% conformer II and 67% of conformer IV.[2]

The presence of three rotating ethyl groups makes it likely that there will be more than one minimum on the potential energy surfaces of chlorotriethylsilane and TEBS. As such, the first task of this work was to perform a conformational study on both systems based on the calculated populations obtained by the application of the Boltzmann distribution equation and the data from the gas phase electron diffraction (GED) experiments. Thereafter, the multiconformer molecular structures of both compounds have been determined using a combination of experimental data from the GED experiments and the results from theoretical ab initio (RHF, MP2) and density functional theory (DFT, B3LYP) calculations. Finally, the IR and Raman spectra of chlorotriethylsilane and TEBS have been recorded. These data, and those from theoretical calculations using the B3LYP method, have been employed to determine a complete vibrational assignment for both molecules. For the vibrational study, conformer IV has been used as a reference, since it is predicted to be the main conformer for both TECS and TEBS. The experimental mixtures for chlorotriethylsilane and TEBS are therefore within two standard deviation of the calculated mixtures, albeit in different directions. Of course, there would also be small amounts of the other three conformers so the indicated uncertainties must be underestimates.

The structures of chlorotriethylsilane and TEBS have been determined experimentally by GED. For each, a model involving the two main conformers was used for the refinement of the experimental data. For chlorotriethylsilane, the lowest RG value was for a composition of 57% of conformer II and 43% of conformer IV, and for TEBS, the best fit represented 33% of conformer II and 67% of conformer IV, which are in good agreement with the results from the theoretical calculations. The vibrational spectra of both chlorotriethylsilane and TEBS have been completely assigned, following similar patterns in both compounds. The proposed assignment includes bands that could only be explained by considering the presence of more than one conformer. Although the majority of the bands could be explained by taking into account only the contributions from conformers II and IV, assignments of some bands used the scaled frequencies predicted for the remaining conformers, specifically, conformers III and V. Additionally, the use of the SQMFF methodology has allowed us to obtain two sets of scaling factors, one for each basis set used for the vibrational assignment. These parameters could, in the future, be transferred to other more reactive or unstable alkylsilane derivatives, such as silicon alkoxides or silanols, which take part in sol?gel processes of industrial interest, in order to predict their vibrational spectra. These data could be used in the monitoring of these processes, for which IR and Raman techniques have proved themselves to be very powerful tools.

Nickel-Catalyzed Reductive Conjugate Addition to Enones Via Allylnickel Intermediates

Reactions are assembled on the bench-top and tolerate a variety of functional groups (aldehyde, ketone, nitrile, sulfone, pentafluorosulfur, and N-aryltrifluoroacetamide), electron-rich iodoarenes, and electron-poor haloarenes. Mechanistic studies have confirmed the first example of a catalytic reductive conjugate addition of organic halides that proceeds via an allylnickel intermediate. Selectivity is attributed to: 1) rapid, selective reaction of LNi0 with chlorotriethylsilane and enone in the presence of other organic electrophiles, and 2) minimization of enone dimerization by ligand steric effects.[3]

Initial reaction development was focused on finding a catalyst that would be selective for the cross-coupling of iodo-benzene with cyclohexenone in presence of chlorotriethylsilane. The combination of three electrophiles could result in multiple by-products, but we primarily observed biphenyl (B), benzene (Ph-H), and silylated enone dimer (E). Notably, we did not observe the formation of desilylated ketone product or products from a Heck-like addition/β-hydride elimination process.  Most other silicon reagents with moderate reactivity and steric bulk formed product in reasonable yield (66–95% yield, entries 5–12). Because chlorotriethylsilane (TES-Cl) was among the most effective reagents and it is available at low cost, we conducted the majority of our reactions in the following sections with TES-Cl. If less reactive silyl enol ether products would be an advantage in synthesis, n-Pr3Si-Cl or TBS-Cl can be used with only a small change in yield.

Given the strong precedent for both arylnickel (I) and allylnickel (II) intermediates, we studied the rate at which iodobenzene, enone, and chlorotriethylsilane react with (L10)Ni0(cod) by monitoring the disappearance of the MLCT band at 450 nm. The results clearly show that iodobenzene reacts much slower than chlorotriethylsilane and enone, consistent with the “enone-first” mechanism. The stoichiometric reaction of in-situ-generated arylnickel IA with cyclohexenone and chlorotriethylsilane exclusively formed biphenyl. Increased yield and selectivity were observed when Mn pre-activated with chlorotriethylsilane was employed with either excess or equimolar amounts of iodobenzene (Entries 4 and 5). Selectivity for product formation over biaryl formation is consistent with the catalytic reaction (entry 7). Of the two potential intermediates, only allylnickel IIA formed the correct product and showed selectivity consistent with the catalytic reaction. With manganese metal as the terminal reductant, the potential exists for the intermediacy of arylmanganese reagents. Reactions conducted without nickel, but with 1.1 equiv of chlorotriethylsilane did not consume aryl iodide over a period of 24 h

References

[1]SHIN ETSU CHEMICAL - JP6044361, 2016, B2

[2]Montejo, Manuel et al. “Conformations, structures, and vibrational spectra of triethylchloro- and triethylbromosilane using theoretical methods, gas phase electron diffraction, and IR and Raman spectroscopy.” The journal of physical chemistry. A vol. 111,15 (2007): 2870-8.

[3]hrestha R, Dorn SC, Weix DJ. Nickel-catalyzed reductive conjugate addition to enones via allylnickel intermediates. J Am Chem Soc. 2013 Jan 16;135(2):751-62.