TY - JOUR
A1 - Shainyan, Bagrat A.
A1 - Kirpichenko, Svetlana V.
A1 - Kleinpeter, Erich
A1 - Shlykov, Sergey A.
A1 - Osadchiy, Dmitriy Yu.
T1 - Molecular structure and conformational analysis of 3-methyl-3-phenyl-3-silatetrahydropyran. Gas-phase electron diffraction, low temperature NMR and quantum chemical calculations
JF - Tetrahedron
N2 - The molecular structure and conformational behavior of 3-methyl-3-phenyl-3-silatetrahydropyran 1 was studied by gas-phase electron diffraction (GED-MS), low temperature C-13 NMR spectroscopy (LT NMR) and theoretical calculations. The 1-Ph-eq and 1-Ph-ax conformers were located on the potential energy surface. Rotation about the Si-C-ph bond revealed the phenyl ring orthogonal to the averaged plane of the silatetrahydropyran ring for 1-Ph-eq and a twisted orientation for 1-Ph-ax. Theoretical calculations and GED analysis indicate the predominance of 1-Ph-ax in the gas phase with the ratio of conformers (GED) 1-Ph-eq:1-Ph-ax=38:62 (Delta G degrees(307)=-0.29 kcal/mol). In solution, LT NMR spectroscopy gives almost the opposite ratio Ph-eq:1-Ph-ax=68:32 (Delta G degrees(103)=0.16 kcal/mol). Simulation of solvent effects using the PCM continuum model or by calculation of the solvent-solute complexes allowed us to rationalize the experimentally observed opposite conformational predominance of the conformers of compound 1 in the gas phase and in solution. (C) 2015 Elsevier Ltd. All rights reserved.
KW - 3-Silatetrahydropyrans
KW - Conformational analysis
KW - Low temperature NMR spectroscopy
KW - Gas-phase electron diffraction
KW - Quantum chemical calculations
Y1 - 2015
U6 - http://dx.doi.org/10.1016/j.tet.2015.03.117
SN - 0040-4020 (print)
VL - 71
IS - 23
SP - 3810
EP - 3818
PB - Elsevier
CY - Oxford
ER -