1,3,2-Dioxathiolane 2,2-dioxides dipole moment

Dioxathiolane 2,2-dioxide, 4,4,5,5-tetramethyl-dipole moment, 6, 865 <77IZV98)... 

Ethylene, /3-(dimethylamino)-nitro-in pyrrole synthesis, 4, 334 Ethylene, dithienyl-in photochromic processes, 1, 387 Ethylene, furyl-2-nitro-dipole moments, 4, 555 Ethylene, l-(3-indolyl)-2-(pyridyl)-photocyclization, 4, 285 Ethylene, l-(2-methyl-3-indolyl)-l,2-diphenyl-synthesis, 4, 232 Ethylene, (phenylthio)-photocyclization thiophenes from, 4, 880 Ethylene carbonate C NMR, 6, 754 microwave spectroscopy, 6, 751 photochemical chlorination, 6, 769 synthesis, 6, 780 Ethylene oxide as pharmaceutical, 1, 157 thiophene synthesis from, 4, 899 Ethylene sulfate — see 2,2-dioxide under 1,3,2-Dioxathiolane... 

The gas-phase dipole moment of 1,2,3-trioxolane was determined to be 3.43 D from microwave spectroscopic studies <88JA799l>. This compares with calculated values of 3.90 D and 4.03 D using SCF and MP2 methods, respectively <89JA2497>. The dipole moment of 1,3,2-dioxathiolane 2-oxide has been measured as 3.65 D <49DOK(69)4i> and 3.74 D <6IJA2105> (both in benzene), and that of 1,3,2-dioxathiolane 2,2-dioxide has been determined to be 5.64 D (in dioxane) <68JHC289>. These results are consistent with the compounds adopting nonplanar conformations. 

Dioxathiolane 2,2-dioxide (21) adopts a puckered conformation in the solid state, as shown by x-ray diffraction (Section 4.15.3.1). In solution, the H NMR spectrum of (21) indicates that the compound undergoes a rapid pseudorotation between twist-envelope forms (Section 4.15.3.3.1) the O NMR spectra of simple derivatives also indicate a rapid conformational equilibrium by pscudorotation, although substitution may act as a barrier to complete ring inversion (Section 4.15.3.3.3). The solution-phase dipole moment of 1,3,2-dioxathiolane 2,2-dioxide is consistent with a nonplanar conformation (Section 4.15.3.8). 

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