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DOI: 10.1039/A607563K (Paper) Reference Section for: J. Chem. Soc., Perkin Trans. 2, 1997, 1365-1368

Conformational analysis of the cis- and trans-1,2-bis(trimethylsilyl)cyclohexanes (BTMSC): molecular mechanics calculations and nuclear magnetic resonance spectroscopy. A preferred diaxial conformation for the trans-isomer

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Roberto Núñez, Rayomand J. Unwalla, Frank K. Cartledge, Soo G. Cho, Bruce H. Riches, Matthew P. Glenn, Natasha L. Hungerford, Lynette K. Lambert, Douglas J. Brecknell and William Kitching

Abstract

Molecular mechanics calculations (MM3-92) suggest that a slightly distorted diaxial chair conformation of trans-1,2-bis(trimethylsilyl)cyclohexane is at least 1.26 kcal mol-1 (1 cal = 4.184 J) lower in steric energy than the diequatorial form, and this is supported by NOED spectra, magnitudes of vic-1H–1H spin coupling constants, and low temperature (190 K) 13C NMR spectroscopic measurements, which place the free energy difference between 1.5 and 1.7 kcal mol-1.

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