Zobrazeno 1 - 10
of 124
pro vyhledávání: '"V A, Bushmelev"'
Autor:
Vyacheslav G. Shubin, V. A. Bushmelev, George E. Salnikov, Alexander M. Genaev, Andrey A. Nefedov
Publikováno v:
RSC Adv.. 4:52831-52835
1 H and 13C NMR studies have shown that the long-lived 9,9-dimethyl-10-R-phenanthrenium cations (R = PhCC, Me, OH) generated in FSO3H–SbF5/SO2ClF/SO2/CD2Cl2 transform into long-lived 7-dihydroxysulfonio-9,9-dimethyl-10-R-phenanthrenium dications. T
Publikováno v:
Russian Journal of Organic Chemistry. 49:1313-1321
According to the NMR data, long-lived 10,10-dimethyl-9-phenylethynyl-9,10-dihydrophenanthren-9-ylium in acid medium undergoes cyclization whose direction is determined by the acidity of the medium. The cyclization in HSO3F-SbF5 superacid involves the
Publikováno v:
Russian Journal of Organic Chemistry. 49:853-859
According to the NMR data, 9-(R-ethynyl)-9-hydroxy-10,10-dimethyl-9,10-dihydrophenanthrenes (R = H, Me, Ph) in superacid medium (HSO3F-SO2ClF) at low temperature undergo dehydroxylation with formation of the corresponding long-lived 10,10-dimethyl-9-
Publikováno v:
Russian Journal of Organic Chemistry. 47:1050-1056
Long-lived 9-cyano-9,10-dimethylphenanthrenyl cation was generated in superacidic medium, and its structure was determined by 1H and 13C NMR spectroscopy. The energy barrier to 1,2-shift of the cyano group in 9-cyano-9,10-dimethylphenanthrenyl cation
Publikováno v:
Russian Journal of Organic Chemistry. 47:1057-1061
The behavior of 10,10-dimethyl-9-trimethylsiloxy-9,10-dihydrophenanthrene-9-carbonitrile in trifluoromethanesulfonic acid and acid systems CF3SO3H-CD2Cl2, HSO3F-SO2ClF-CD2Cl3, and CF3COOH-CD2Cl2 were studied by NMR spectroscopy. Principal reaction sc
Publikováno v:
Russian Journal of Organic Chemistry. 46:520-527
DFT quantum-chemical calculations predicted structural nonrigidity of 9,9,10-trimethyl- and 4,5,9,9,10-pentamethylphenanthrenylium ions. The cross section of the potential energy surface at the nonrigidity coordinate for the first of these ions is sy
Publikováno v:
Russian Journal of Organic Chemistry. 45:1175-1180
Rearrangements of 6b,7,8,8a-tetramethyl-6b,8a-dihydrocyclobut[a]acenaphthylene in acids were investigated by NMR spectroscopy. The initially formed 3b,4-exo,4a,5-tetramethyl-3b,4,4a,5-tetrahydro-4H-cyclopropa[a]phenalen-5-yl cation and its endo-epime
Publikováno v:
Russian Journal of Organic Chemistry. 43:1656-1660
The kinetics of degenerate pendular rearrangement of 3b,exo-4,4a,5-tetramethyl-3b,4,4a,5-tetrahydro-4H-cyclopropa[a]phenalen-5-yl cation and its endo epimer, generated under conditions ensuring their long life, were studied by dynamic NMR spectroscop
Publikováno v:
Russian Journal of Organic Chemistry. 42:1257-1263
1H NMR study has shown that long-lived 9-R-9,10-dimethylphenanthren-9-yl cations (R = isopropenyl, trans-1-methylprop-1-en-1-yl) generated in the system HSO3F-SO2ClF-CD2Cl2 at −130°C undergo degenerate rearrangement via 1,2-vinyl shifts (ΔG’ =
Publikováno v:
Russian Journal of Organic Chemistry. 42:220-226
It was discovered by means of dynamic NMR that the 1-(cis-1-methylprop-1-en-1-yl)-1,2-dimethylacenaphthylenonium ion generated under conditions of “long life” for carbocations underwent fast (ΔG#35.8 kJ mol−1 at −103°C) degenerate 1,2-shift