15411-19-5 Purity
97%
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Specification
Using dirhodium complexes as catalysts, the primary C(sp3)-H bond of silylethyl groups and the secondary C(sp3)-H bond of silacycloalkanes can be selectively converted into C-N at the β position of the silicon atom. Based on the kinetic studies, the C-H insertion step is not the turnover-limiting step, but the selectivity-determining step. For example, using 1,1-dimethylsilacyclopentane as the substrate and Rh2(OAc)4 as the catalyst model, the transition state (TS) structure of the C-H bond cleavage step was calculated by DFT.
Computational details
· All calculation reported in the present study were carried out using density functional theory (DFT) with (U)M06 or B3PW91 functional, as implemented in the Gaussian 09.
· For geometry optimizations, the 6-31G(d,p) basis set was used for the H, C, N, O, Si, Cl elements, and the LANL2DZ basis set and pseudopotential for Rh.
· Based on these optimized geometries, single-point energy calculations were performed using the 6-311++G(2d,2p) basis set for the H, C, N, O, Si, Cl elements, and the SDD basis set and pseudopotential for Rh with solvents effects simulated by SMD solvent model.
· The stationary points were confirmed as minima or transition state by analytical frequency calculations as the same theory level as the geometry optimizations.
The monochlorination of 1,1-dimethylsilacyclopentane results primarily in the formation of the chloromethyl derivatives. The addition of free radical catalysts does not substantially alter the extent of methyl chlorination, but does result in increased attack on the ring carbon β to the silicon and decreased attack on the ring carbon α to the silicon. The chemistry leading to the assignment of structures for the monochloro isomers of 1,1-dimethylsilacyclopentane is discussed.
· In this investigation, 1,1-dimethylsilacyclopentane (I) has been observed to undergo chlorination both with chlorine gas and with sulfuryl chloride, in the presence or absence of free radical catalysts, to yield predominantly 1-chloromethyl-1-methylsilacyclopentane (Ⅲ).
· The use of free radical catalysts accelerated the reaction to some extent, but the chloromethyl isomer was still observed to be the major product. On the other hand, distribution between the 2-chlorosilacyclopentane (IV) and the 3-chloro isomer (V) was affected.
· Without catalyst, IV was observed in the higher yield; but with catalyst, V was predominant.
· Confirmation of this identification was accomplished by reaction of V with methylmagnesium bromide, resulting in the formation of 1-trimethylsilyl-3-butene (VI). Compounds III and IV were unaffected by these reactions.
Silicone intermediate
In the experiment, 1,1-dimethylsilacyclopentane is a useful silicone intermediate.
The molecular formula is C6H14Si.
The molecular weight is 114.26 g/mol.
The IUPAC Name is 1,1-dimethylsilolane.
The InChI is InChI=1S/C6H14Si/c1-7(2)5-3-4-6-7/h3-6H2,1-2H3.
The InChIKey is KDQBKCRYCZJUAE-UHFFFAOYSA-N.
The canonical SMILES is C[Si]1(CCCC1)C.
The CAS number is 1072-54-4.
The DSSTox Substance ID is DTXSID80147942.
The Nikkaji Number is J364.614I.
Yes, 1,1-Dimethylsilacyclopentane is canonicalized.