Stereodynamics of 1,3,5-tris(trifluoromethylsulfonyl)-1,3,5-triazinane: experimental and theoretical analysis

Shainyan, B. А.; Meshcheryakov, V. I.; Albanov, A. I.; Sigalov, M. V.

doi:10.1016/j.tetlet.2005.07.068

Cited by 15 publications

(20 citation statements)

References 7 publications

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“…The 1 H NMR spectrum of dioxazinane VI is temperature-dependent * in the fashion characteristic of the six-membered heterocycles similarly to that we have previously observed for its close analogs IV [2] and V [3]. It turned out that under mild conditions (20°C, 6 h) just 5-trifluoromethylsulfonyl-1,3-dioxazinane (VI) was the main product.…”

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confidence: 63%

10.1007/s11178-008-2020-9

2010

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Acid-catalyzed reaction of trifluoromethanesulfonamide with paraformaldehyde in ethyl acetate led to the formation of oxymethylated products that did not form in the reaction carried out in sulfuric acid. Following products were obtained: 5-trifluoromethylsulfonyl-1,3-dioxazinane, 3,7-bis-(trifluoromethylsulfonyl)-1,5,3,7dioxadiazocane, and a complex of trifluoromethanesulfonamide with 2,4,8,10-tetraoxospiro[5,5]undecene, 1:1. The spiroring resulted from the cyclization of pentaerythritol under the action of formaldehyde. The pentaerythritol formed in its turn by oxymethylation of the methyl group of ethyl acetate with paraformaldehyde followed by the reduction of the COOEt group into CH 2 OH by the formaldehyde.We showed formerly that the reaction of trifluoromethanesulfonamide CF 3 SO 2 NH 2 (I) with paraformaldehyde in sulfuric acid led to the formation of linear and cyclic condensation products II-V [1].

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confidence: 63%

10.1007/s11178-008-2020-9

2010

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“…It is interesting to compare the strong (for 1 ) or complete (for 2 ) predominance of the outward versus inward rotamers with the ratio of these rotamers in the earlier studied 1,3,5‐triheterocyclohexanes and 1,4‐diheterocyclohexanes. Thus, for 1,3,5‐tris(trifluoromethylsulfonyl)‐1,3,5‐triazinane, 3,5‐bis(trifluoromethylsulfonyl)‐1,3,5‐oxadiazinane, and 5‐(trifluoromethylsulfonyl)‐1,3,5‐dioxaazinane, the rotamers with one CF 3 group inward were found to be predominant with the ratio of the rotamers in the frozen equilibria equal to 4:1, 7:1, and 5:1, respectively . As distinct of that, 1‐(trifluoromethylsulfonyl)piperidine, 4‐(trifluoromethylsulfonyl)morpholine, 4‐(trifluoromethylsulfonyl)thiomorpholine 1,1‐dioxide, and 1,4‐bis(trifluoromethylsulfonyl)piperazine prefer the outward rotamers and show the equilibrium ratio of 4:1, 4:1, 8:1 and 3:28:69, respectively …”

Section: Resultsmentioning

confidence: 94%

“…As we have shown Scheme 2. R = Me, 4 [2] ; i-Pr, 5 [2] ; SO 2 CF 3 , 2, this work X N SO 2 CF 3 X for the reference compounds 3-5 and other related species having the trifluoromethylsulfonyl group at the endocyclic nitrogen atom, [5][6][7][8][9] two dynamic processes, namely, the ring inversion and the rotation about the N-S bond can occur. The inversion at the nitrogen atom (like in 1,3,5-trialkyl-1,3,5-triazinanes) [10,11] can be ruled out because the latter in perfluoroalkanesulfonamides was shown to be practically planar rather than pyramidal.…”

Section: Introductionmentioning

confidence: 99%

Conformational analysis of 4,4‐dimethyl‐1‐(trifluoromethylsulfonyl)‐1,4‐azasilinane and 2,2,6,6‐tetramethyl‐4‐(trifluoromethylsulfonyl)‐1,4,2,6‐oxazadisilinane

Shainyan

Suslova

Kleinpeter

2011

J of Physical Organic Chem

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4,4‐Dimethyl‐1‐(trifluoromethylsulfonyl)‐1,4‐azasilinane 1 and 2,2,6,6‐tetramethyl‐4‐(trifluoromethylsulfonyl)‐1,4,2,6‐oxazadisilinane 2 were studied by variable temperature dynamic 1H, 13C, 19F NMR spectroscopy and theoretical calculations at the DFT (density functional theory) and MP2 (Møller‐Plesset 2) levels of theory. Both kinetic (barriers to ring inversion) and thermodynamic data (frozen conformational equilibria) could be obtained for the two compounds. The computations revealed two minima on the potential energy surface for molecules 1 and 2 corresponding to the rotamers with the CF3SO2 group directed ‘inward’ and ‘outward’ the ring, the latter being 0.2–0.4 kcal/mol (for 1) and 1.1 kcal/mol (for 2) more stable than the former. The vibrational calculations at the DFT and MP2 levels of theory give the values of the free energy difference ΔGo for the ‘inward’ ‘outward’ equilibrium consistent with those determined from the experimentally measured ratio of the rotamers. The structure of crystalline compound 2 was ascertained by X‐ray diffraction analysis. Copyright © 2011 John Wiley & Sons, Ltd.

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“…At low temperature compound 50 exhibits a ring inversion process with a barrier (∆G ϶ ) of 13.5 kcal mol -1 between two degenerate C 3 forms and a S-N bond rotation process between two unequally populated conformers (∆G ϶ = 13.0 kcal mol -1 ), the more stable having C s symmetry and the less stable C 3v symmetry. [111] When the three sulfonyl substituents are not identical, as in the case of 51, DFT calculations predict that the compound can exist in three forms, due to the restricted Ninversion and N-S bond rotation. Two of these are sufficiently populated to be experimentally observed with a 6:1 relative proportion, the major having C s symmetry and the minor C 1 symmetry.…”

Section: Miscellaneamentioning

confidence: 99%