TY  - JOUR
A1  - Lazareva, Nataliya F.
A1  - Shainyan, Bagrat A.
A1  - Kleinpeter, Erich
T1  - 4-Alkyl-2,2,6,6-tetramethyl-1,4,2,6-oxaazadisilinanes : synthesis, structure, and conformational analysis
N2  - 4-Alkyl-2,2,6,6-tetramethyl-1,4,2,6-oxaazadisilinanes RN[CH2Si(Me)2]2O [R = Me (1), i-Pr (2)] were synthesized by two methods which provided good yields up to 84%. Low temperature NMR study of compounds (1) and (2) revealed a frozen ring inversion with the energy barriers of 8.5 and 7.7 kcal/mol at 163 and 143 K, respectively, which is substantially lower than that for their carbon analog, N-methylmorpholine. DFT calculations performed on the example of molecule (1) showed that N-Meax conformer to exist in the sofa conformation with the coplanar fragment C-Si-O-Si-C, and its N-Meeq conformer in a flattened chair conformation.
Y1  - 2010
UR  - http://www3.interscience.wiley.com/cgi-bin/jhome/4569
U6  - https://doi.org/10.1002/Poc.1605
SN  - 0894-3230
ER  - 
TY  - JOUR
A1  - Kirpichenko, Svetlana V.
A1  - Kleinpeter, Erich
A1  - Shainyan, Bagrat A.
T1  - Conformational analysis of 3,3-dimethyl-3-silathiane, 2,3,3-trimethyl-3-silathiane and 2-trimethylsilyl-3,3- dimethyl-3-silathianeùpreferred conformers, barriers to ring inversion and substituent effec
N2  - The first conformational analysis of 3-silathiane and its C-substituted derivatives, namely, 3,3-dimethyl-3- silathiane 1, 2,3,3-trimethyl-3-silathiane 2, and 2-trimethylsilyl-3,3-dimethyl-3-silathiane 3 was performed by using dynamic NMR spectroscopy and B3LYP/6-311G(d,p) quantum chemical calculations. From coalescence temperatures, ring inversion barriers ;G; for 1 and 2 were estimated to be 6.3 and 6.8;kcal/mol, respectively. These values are considerably lower than that of thiacyclohexane (9.4;kcal/mol) but slightly higher than the one of 1,1- dimethylsilacyclohexane (5.5;kcal/mol). The conformational free energy for the methyl group in 2 (;;G°;=;0.35;kcal/mol) derived from low-temperature 13C NMR data is fairly consistent with the calculated value. For compound 2, theoretical calculations give ;E value close to zero for the equilibrium between the 2-Meax and 2-Meeq conformers. The calculated equatorial preference of the trimethylsilyl group in 3 is much more pronounced (;;G°;=;1.8;kcal/mol) and the predominance of the 3-SiMe3 eq conformer at room temperature was confirmed by the simulated 1H NMR and 2D NOESY spectra. The effect of the 2-substituent on the structural parameters of 2 and 3 is discussed.
Y1  - 2010
SN  - 0894-3230
ER  - 
TY  - JOUR
A1  - Shainyan, Bagrat A.
A1  - Moskalik, Mikail Yu
A1  - Starke, Ines
A1  - Schilde, Uwe
T1  - Formation of unexpected products in the attempted aziridination of styrene with trifluoromethanesulfonyl nitrene
N2  - The reaction of styrene with trifluoromethanesulfonyl nitrene generated from trifluoromethanesulfonamide in the system (t-BuOCl+NaI) results in the formation of trifluoro-N-[2-phenyl-2-(trifluoromethylsulfonyl) aminoethyl]methanesulfonamide, 1-pheny1-2-iodo-ethanol, and 2,5-diphenyl-1,4-bis(trifluoromethyl sulfonyl)piperazine rather than the expected product of aziridination, 2-phenyl-1-(trifluoromethylsulfonyl) aziridine. The mechanism of the reaction is discussed.
Y1  - 2010
UR  - http://www.sciencedirect.com/science/journal/00404020
U6  - https://doi.org/10.1016/j.tet.2010.08.070
SN  - 0040-4020
ER  -