%0 Journal Article %1 Ehlend.1995 %A Ehlend, Anja %A Hausen, H.-D. %A Kaim, Wolfgang %A Lichtblau, Alexander %A Schwarz, Wolfgang. %D 1995 %J Journal of Organometallic Chemistry %K bond carbon carbonyl crystal cycloaddn dioxide disulfide insertion mol nitrogen prepn pyrazine silicon silicon;sulfide silyl;diepiazanothiocinopyrazinethione structure;insertion sulfide %N 1-2 %P 283--292 %R 10.1016/0022-328X(95)05673-D %T Insertion of CO2, COS and CS2 into the N-Si bond of extremely electron-rich 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine and formation of a new poly(N,S) heterocyclic system by multiple cycloaddition %V 501 %X 1,4-Bis(trimethylsilyl)-1,4-dihydropyrazine (1), a very-electron-rich N-silyl-enamine with eight conjugated p electrons in the planar six-membered ring, exhibits different reactivity with respect to heterocumulenes X:C:Y (X, Y = O,S). Carbon dioxide is slowly inserted into one N-Si bond to give an electron-rich O-silylurethane functionality. Significant insertion into the second N-Si bond occurs only under CO2 pressure. 1H NMR spectroscopy of the products from all insertion reactions reveals strongly solvent-dependent chem. shifts and restricted rotation around the N-C(:X) bonds. Carbonyl sulfide reacts more rapidly with 1 than does CO2 to yield a structurally characterized O-silylthiourethane deriv., only one mol. of COS could be added. Carbon disulfide reacts rapidly with 1 under partial oxidative desilylation as evident from the formation of pyrazine; in addn. to some insertion, a novel polyheterocyclic system I is formed as the main product. The crystallog. characterized red 5r,10c;6t,9t-diepiazano-thiocino4,5-bpyrazine-8-thione deriv. I is formed by cycloaddn. between CS2 and two equiv. of 1; the mol. I contains one boat- and one chair-shaped polyhydropyrazine ring and a close to tetrahedral arrangement of the four Me3Si groups. on SciFinder(R)

@article{Ehlend.1995, abstract = {1,4-Bis(trimethylsilyl)-1,4-dihydropyrazine (1), a very-electron-rich N-silyl-enamine with eight conjugated \textgreek{p} electrons in the planar six-membered ring, exhibits different reactivity with respect to heterocumulenes X:C:Y (X, Y = O,S). Carbon dioxide is slowly inserted into one N-Si bond to give an electron-rich O-silylurethane functionality. Significant insertion into the second N-Si bond occurs only under CO2 pressure. 1H NMR spectroscopy of the products from all insertion reactions reveals strongly solvent-dependent chem. shifts and restricted rotation around the N-C(:X) bonds. Carbonyl sulfide reacts more rapidly with 1 than does CO2 to yield a structurally characterized O-silylthiourethane deriv., only one mol. of COS could be added. Carbon disulfide reacts rapidly with 1 under partial oxidative desilylation as evident from the formation of pyrazine; in addn. to some insertion, a novel polyheterocyclic system I is formed as the main product. The crystallog. characterized red 5r,10c;6t,9t-diepiazano-thiocino[4,5-b]pyrazine-8-thione deriv. I is formed by cycloaddn. between CS2 and two equiv. of 1; the mol. I contains one boat- and one chair-shaped polyhydropyrazine ring and a close to tetrahedral arrangement of the four Me3Si groups. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Ehlend, Anja and Hausen, H.-D. and Kaim, Wolfgang and Lichtblau, Alexander and Schwarz, Wolfgang.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/273c3f97a3ac8da57aa3dacc16ddbe90c/huebleriac}, doi = {10.1016/0022-328X(95)05673-D}, interhash = {3b81b002375490be0bef077e38fc9e92}, intrahash = {73c3f97a3ac8da57aa3dacc16ddbe90c}, journal = {Journal of Organometallic Chemistry}, keywords = {bond carbon carbonyl crystal cycloaddn dioxide disulfide insertion mol nitrogen prepn pyrazine silicon silicon;sulfide silyl;diepiazanothiocinopyrazinethione structure;insertion sulfide}, number = {1-2}, pages = {283--292}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Insertion of CO2, COS and CS2 into the N-Si bond of extremely electron-rich 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine and formation of a new poly(N,S) heterocyclic system by multiple cycloaddition}, volume = 501, year = 1995 }