Reaction of 10,10-dimethyl-9-trimethylsiloxy-9,10-dihydrophenanthrene-9-carbonitrile with acids

Abstract

The behavior of 10,10-dimethyl-9-trimethylsiloxy-9,10-dihydrophenanthrene-9-carbonitrile in trifluoromethanesulfonic acid and acid systems CF 3 SO 3 H-CD 2 Cl 2 , HSO 3 F-SO 2 ClF-CD 2 Cl 2 , and CF 3 COOH-CD 2 Cl 2 were studied by NMR spectroscopy. Principal reaction schemes were determined; the first step in these schemes is protonation of the initial compound at the oxygen or nitrogen atom.We found [1] that 10,10-dimethyl-9-trimethylsilyloxy-9,10-dihydrophenanthrene-9-carbonitrile (I) in superacid media undergoes ionization with formation of long-lived 9-cyano-9,10-dimethylphenanthrenyl cation (II) (Scheme 1). Apart from signals belonging to cation II, the NMR spectra contained a number of additional signals indicating other schemes of reactions of nitrile I with superacids. The goal of the present work was to elucidate these schemes. located in the region δ 7.6-8.9 ppm. In the 13 C NMR spectrum we observed only signals from conformer IIIa, δ C , ppm: 27.1 (9-CH 3 ), 46.1 (C 9 ), 215.7 (C 10 ); aromatic carbon atoms resonated in the range δ C 120-160 ppm. According to the NMR data, the ratio of cations II and III was about 1 : 1.

Interaction of acetonitrile with trifluoromethanesulfonic acid: unexpected formation of a wide variety of structures

“…Almost from the very beginning of the reaction a signal for Tf 2 O appears in the 19 F NMR spectra. Its identification has been made from the observation of a long-range spin-spin coupling constant 19 F-19 F (J = 0.85 Hz in the 13 through a maximum and then decreases. When the reaction mixture is kept for a long time an additional species appears, its structure is tentatively assigned as 6 on the basis of its 2D NMR data.…”

“…General methods and materials NMR and ESI-MS spectra were obtained at the Chemical Service Centre of the Siberian Branch of the Russian Academy of Sciences. Multinuclear NMR spectra ( 1 H, 2 H, 13 C, 15 N, 19 F) were obtained on Bruker AV-600 (resonance frequency for 1 H 600.3 MHz), AV-400 (400.13 MHz), and AV-300 (300.13 MHz) spectrometers. Chemical shifts for 1 H, 2 H and 13 C measured relative to the internal standard CD 2 Cl 2 (δ 5.33 ppm for 1 H and 2 H, 53.6 ppm for 13 C), for 15 N relative to external NH 3 , for 19 F relative to external CFCl 3 .…”

“…Multinuclear NMR spectra ( 1 H, 2 H, 13 C, 15 N, 19 F) were obtained on Bruker AV-600 (resonance frequency for 1 H 600.3 MHz), AV-400 (400.13 MHz), and AV-300 (300.13 MHz) spectrometers. Chemical shifts for 1 H, 2 H and 13 C measured relative to the internal standard CD 2 Cl 2 (δ 5.33 ppm for 1 H and 2 H, 53.6 ppm for 13 C), for 15 N relative to external NH 3 , for 19 F relative to external CFCl 3 . For structure elucidation and NMR signal assignment 2D correlation spectra 1 H-1 H (NOESY, ROESY with mixing times τ m = 0.4-0.7 s), 1 H-13 C (HSQC, HMBC), 1 H-15 N (HMBC), and heteronuclear ( 19 F → 1 H) NOE difference spectra were used.…”

Long-lived 9-cyano-9,10-dimethylphenanthrenyl cation. Migration of cyano group in carbocations

“…The exchange NMR spectra were copy the lower limit of that barrier (ΔG ≠ > 92 kJ/mol). It should also be noted that the reaction of trimethylsilyl ether II with acids, apart from long-lived cation I, gives rise to other products whose structure and mechanism of formation were considered in [25].…”

Synthesis of tertiary arylamines: Lewis acid-catalyzed direct reductive N-alkylation of secondary amines with ketones through an alternative pathway

“…When 1-phenylethanol was reacted in absence of N-methylaniline, styrene and stilbene derivate were detected, which indicates that reaction might involve carbocation intermediate (Scheme 2b). 20 The formation of 12K…”