5161-17-1Relevant academic research and scientific papers
Stereoelectronic Effects: Perlin Effects in Thiane-Derived Compounds
Basche, Luis,Jung, Sebastian T.,Luy, Burkhard,Podlech, Joachim,Reinsperger, Tony
, (2020/04/15)
Stereoelectronic effects in thianes and thiane-derived sulfoxides, sulfones, sulfilimines, and sulfoximines were investigated by measuring 1JC,H coupling constants and by identification of normal and reversed Perlin effects, i.e., of differences in the coupling constants for equatorial and axial C–H bonds in the methylene groups of six-membered rings. The Perlin effects were correlated with results from natural bond orbital (NBO) analyses. NMR experiments were performed with conformationally restricted dimethyl- or tert-butyl-substituted derivatives, while the parent compounds were used for calculations. It turned out that the coupling constants are not only strongly influenced by stereoelectronic interactions with antiperiplanar C–H, C–C, C–O, and C–N bonds, but by the s character of the respective C–H bonds' carbon orbital as well.
Regioselective chlorination of phenols in the presence of tetrahydrothiopyran derivatives
Smith, Keith,Williams, Des,El-Hiti, Gamal A.
, p. 529 - 538 (2019/06/13)
Four six-membered cyclic sulfides, namely tetrahydrothiopyran, 3-methyltetrahydrothiopyran, 4-methyltetrahydrothiopyran and 4,4-dimethyltetrahyrdrothiopyran have been used as moderators in chlorination reactions of various phenols with sulfuryl chloride in the presence of aluminum or ferric chloride. On chlorination of phenol, ortho-cresol and meta-cresol the para/ortho chlorination ratios and yields of the para-chloro isomers are higher than when no cyclic sulfide is used for all of the cyclic sulfides, but chlorination of meta-xylenol is less consistent, with some cyclic sulfides producing higher p/o ratios and others producing lower ratios than reactions having no sulfide present.
The regiochemistry of cyclization of α-sulfenyl-, α-sulfinyl-, and α-sulfonyl-5-hexenyl radicals: Procedures leading to regioselective syntheses of cyclic sulfones and sulfoxides
Della, Ernest W.,Graney, Sean D.
, p. 3824 - 3835 (2007/10/03)
A study of the cyclization of α-sulfenyl-, α-sulfinyl-, and α-sulfonyl-5-hexenyl and 5-methyl-5-hexenyl radicals reveals a unique contrast in the mode of ring closure of the radicals. In the case of the 5-hexenyl radicals, the sulfinyl-substituted species displays unexpected regioselectivity relative to its analogues. Thus, while the α-S- and α-SO2-5-hexenyl radicals give measurable and increasing quantities of 6-endo product, the α-sulfinyl species cyclizes with high selectivity (95.5:4.5) via a 5-exo mode. By contrast, ring closure of the 5-methyl-5-hexenyl radicals is found to give substantially the 6-endo product in all cases. It is the α-sulfonyl-5-methyl-5-hexenyl radical that now exhibits high regioselectivity (97.5:2.5) for 6-endo closure: an illustration of the synthetic value of this observation is the independent synthesis of the model cyclohexyl sulfone 61 in high yield. It is found that ring closure under the conditions employed occurs irreversibly in all cases.
Regioselectivity of ring closure of 2-thia- and 2-sulfonyl-5-methyl-5-hexenyl radicals
Della, Ernest W.,Graney, Sean D.
, p. 4065 - 4067 (2007/10/03)
(matrix presented) Ring closure of the α-substituted radicals 4 (X = S, SO2) is observed to be irreversible and to lead to significant amounts of the product of 6-endo cyclization. Indeed, reduction of the sulfonyl-based radical 4 (X = SO2
