Substituted trimethylene sulfites

On the basis of dipole moment measurements [100] and IR [101] and NMR [102] studies it has been suggested that twist forms are populated appreciably when a jy/T-diaxial interaction occurs between the S=0 and a methyl group at C-4 or C-6. However, these interpretations have been questioned by Pihlaja and coworkers [103,104], who examined NMR data on 2-oxo-l,3,2-dioxathiane and 39 methyl derivatives and preclude significant contributions from twist forms. 

in Organic Sulfur Chemistry (F. Bernardi, I. G. Csizmadia and A. Mangini, eds), pp. 133-190. Elsevier, Amsterdam (1985). 

Tetrahydrothiophene-l-oxide has also been studied by gas-phase electron diffraction. The S=0 bond was found to adopt a pseudo-axial orientation G. Forgacs, G. Schultz, 

Hargittai, I. Jalsovszky and A. Kucsman, J. Chem. Soc., Faraday Trans. 2, 85, 303 

also U. Burkert and N.L. Allinger, Molecular Mechanics, ACS Monograph 177, pp. 241-242. American Chemical Society, Washington, DC (1982) 

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