T. Kanzian, T. A. Nigst, A. Maier, S. Pichl, H. Mayr
FULL PAPER
J. Am. Chem. Soc. 1979, 101, 4708–4713; c) L. A. P. Kane-Ma-
guire, E. D. Honig, D. A. Sweigart, Chem. Rev. 1984, 84, 525–
543; d) C. D. Ritchie, Can. J. Chem. 1986, 64, 2239–2250; e)
C. F. Bernasconi, M. Panda, J. Org. Chem. 1987, 52, 3042–
3050; f) Z. Rappoport, A. Topol, J. Org. Chem. 1989, 54, 5967–
5977; g) N. S. Nudelman, J. Phys. Org. Chem. 1989, 2, 1–14; h)
C. F. Bernasconi, M. W. Stronach, J. Am. Chem. Soc. 1991,
113, 2222–2227; i) J. P. Richard, T. L. Amyes, T. Vontor, J. Am.
Chem. Soc. 1992, 114, 5626–5634; j) C. F. Bernasconi, A. E.
Leyes, J. Am. Chem. Soc. 1993, 115, 7513–7514; k) L. García-
Río, E. Iglesias, J. R. Leis, M. E. Peña, A. Ríos, J. Chem. Soc.
Perkin Trans. 2 1993, 29–37; l) C. K. M. Heo, J. W. Bunting, J.
Chem. Soc. Perkin Trans. 2 1994, 2279–2290; m) B. Varghese,
S. Kothari, K. K. Banerji, Int. J. Chem. Kinet. 1999, 31, 245–
252; n) A. D. Allen, T. T. Tidwell, J. Org. Chem. 1999, 64, 266–
271; o) M. R. Crampton, J. Delaney, L. C. Rabbitt, J. Chem.
Soc. Perkin Trans. 2 1999, 2473–2480; p) J. P. Richard, M. M.
Toteva, J. Crugeiras, J. Am. Chem. Soc. 2000, 122, 1664–1674;
q) H. K. Oh, J. H. Yang, H. W. Lee, J. Org. Chem. 2000, 65,
5391–5395; r) I.-H. Um, J.-S. Min, J.-A. Ahn, H.-J. Hahn, J.
Org. Chem. 2000, 65, 5659–5663; s) C. F. Bernasconi, C. White-
sell, R. A. Johnson, Tetrahedron 2000, 56, 4917–4924; t) E. A.
Castro, M. G. Ruiz, J. G. Santos, Int. J. Chem. Kinet. 2001, 33,
281–287; u) N. C. de Lucas, J. C. Netto-Ferreira, J. Andraos,
J. C. Scaiano, J. Org. Chem. 2001, 66, 5016–5021; v) D. Rajar-
athnam, T. Jeyakumar, P. A. Nadar, Int. J. Chem. Kinet. 2002,
34, 366–373; w) H. K. Oh, T. S. Kim, H. W. Lee, I. Lee, Bull.
Korean Chem. Soc. 2003, 24, 193–196; x) P. M. Mancini, G. G.
Fortunato, L. R. Vottero, J. Phys. Org. Chem. 2004, 17, 138–
147; y) H. K. Oh, I. K. Kim, H. W. Lee, I. Lee, J. Org. Chem.
2004, 69, 3806–3810; z) M. R. Crampton, T. A. Emokpae, C.
Isanbor, J. Phys. Org. Chem. 2006, 19, 75–80.
a) C. G. Swain, C. B. Scott, J. Am. Chem. Soc. 1953, 75, 141–
147; b) C. D. Ritchie, Acc. Chem. Res. 1972, 5, 348–354; c)
C. D. Ritchie, R. J. Minasz, A. A. Kamego, M. Sawada, J. Am.
Chem. Soc. 1977, 99, 3747–3753; d) C. D. Ritchie, C. Kubisty,
G. Y. Ting, J. Am. Chem. Soc. 1983, 105, 279–284.
H. Mayr, M. Patz, Angew. Chem. 1994, 106, 990–1010; Angew.
Chem. Int. Ed. Engl. 1994, 33, 938–957.
a) S. Minegishi, H. Mayr, J. Am. Chem. Soc. 2003, 125, 286–
295; b) F. Brotzel, Y. C. Chu, H. Mayr, J. Org. Chem. 2007, 72,
3679–3688.
a) H. Mayr, T. Bug, M. F. Gotta, N. Hering, B. Irrgang, B.
Janker, B. Kempf, R. Loos, A. R. Ofial, G. Remennikov, H.
Schimmel, J. Am. Chem. Soc. 2001, 123, 9500–9512; b) R. Lu-
cius, R. Loos, H. Mayr, Angew. Chem. 2002, 114, 97–102; An-
gew. Chem. Int. Ed. 2002, 41, 91–95; c) H. Mayr, B. Kempf,
A. R. Ofial, Acc. Chem. Res. 2003, 36, 66–77; d) H. Mayr,
A. R. Ofial, Pure Appl. Chem. 2005, 77, 1807–1821; e) H. Mayr,
A. R. Ofial, J. Phys. Org. Chem. 2008, 21, 584–595.
cedures. 2,2,2-Trifluoroethylamine (2), tert-butylamine (3), iso-
propylamine (4), ethanolamine (5), benzylamine (6), allylamine (7),
n-propylamine (8), n-butylamine (9), bis(2-methoxyethyl)amine
(10), di-n-propylamine (11), diethylamine (12), morpholine (13),
piperidine (14), and pyrrolidine (15) were purchased and purified
by distillation prior to use. 1H (300 or 400 MHz), 13C (75.5 or
100 MHz), and 19F NMR (282 MHz) spectra were recorded a
Bruker ARX 300 or Varian Inova 400 instrument. Mass spectra
were recorded with a MAT 95 Q instrument.
Reactions: The product of the reaction of trifluoroethylamine (2)
with the benzhydrylium salt 1hBF4 was synthesized by the addition
of 2 (70 µL, 0.88 mmol) to a mixture of 1hBF4 (0.15 g, 0.44 mmol)
and K2CO3 (0.6 g, 4 mmol) in acetonitrile (8 mL) at 20 °C. Diethyl
ether was added and the solution was washed with 2 NaOH,
dried, filtered, and the solvents evaporated in vacuo. The products
of the reactions of the amines 3–9 with the benzhydrylium salt
1hBF4 were synthesized by the addition of the amines (0.60 mmol)
to stirred solutions of the benzhydrylium salt (0.10 g, 0.30 mmol)
in acetonitrile (8 mL) at 20 °C. Diethyl ether was added and the
solutions were washed with 2 NaOH, dried, filtered, and the sol-
vents evaporated in vacuo. The products of the reactions of the
amines 12–15 with the benzhydrylium salt 1hBF4 were synthesized
by dropwise addition of acetonitrile solutions (3 mL) of the amines
(ca. 0.7 mmol) to stirred solutions of the benzhydrylium salt (ca.
0.07 g, 0.2 mmol) in acetonitrile (10 mL) at 20 °C. The solvent was
removed under reduced pressure, the remaining solid was extracted
with diethyl ether, and the solvent was evaporated in vacuo. For
details and characterization of the products see the Supporting In-
formation.
[2]
Kinetics: The kinetics of the reactions of the benzhydrylium ions
with the amines were followed by UV/Vis spectrophotometry by
using work-stations similar to those described previously.[5a,23] For
slow reactions (τ1/2 Ͼ 10 s) the UV/Vis spectra were collected at
different times by using a J&M TIDAS diode array spectrophotom-
eter connected to a Hellma 661.502-QX quartz Suprasil immersion
probe (5 mm light path) by fiber optic cables with standard SMA
connectors. All the kinetic measurements were carried out in
Schlenk glassware with the exclusion of moisture. The temperature
of the solutions during the kinetic studies was maintained to within
Ϯ0.1 °C by using circulating bath cryostats and monitored with
thermocouple probes that were inserted into the reaction mixture.
Stopped-flow spectrophotometer systems (Applied Photophysics
SX.18MV-R or Hi-Tech SF-61DX2) were used to investigate fast
[3]
[4]
[5]
reactions of benzhydrylium ions with nucleophiles (10 ms Ͻ τ1/2
Ͻ
10 s). The kinetic runs were initiated by mixing equal volumes of
acetonitrile solutions of the amines and the benzhydrylium salts.
Concentrations and rate constants for the individual kinetic experi-
ments are given in the Supporting Information.
[6]
[7]
[8]
T. B. Phan, C. Nolte, S. Kobayashi, A. R. Ofial, H. Mayr, J.
Am. Chem. Soc. 2009, 131, 11392–11401.
T. B. Phan, M. Breugst, H. Mayr, Angew. Chem. 2006, 118,
3954–3959; Angew. Chem. Int. Ed. 2006, 45, 3869–3874.
a) W. P. Jencks, Chem. Soc. Rev. 1981, 10, 345–375; b) J. P.
Richards, in: Advances in Carbocation Chemistry (Ed.: X. Cre-
ary), JAI Press, Greenwich, London, 1989, vol. 1, pp. 121–169;
c) T. L. Amyes, M. M. Toteva, J. P. Richard, in: Reactive Inter-
mediate Chemistry (Eds.: R. A. Moss, M. S. Platz, M.
Jones Jr.), Wiley-Interscience, Hoboken, NJ, 2004, pp. 41–68;
d) J. P. Richard, T. L. Amyes, M. M. Toteva, Y. Tsuji, Adv.
Phys. Org. Chem. 2004, 39, 1–26.
Supporting Information (see also the the footnote on the first page
of this article): Preparative procedures, product characterization
and details of the individual runs of the kinetic experiments are
available.
Acknowledgments
[9]
a) R. A. McClelland, N. Banait, S. Steenken, J. Am. Chem.
Soc. 1989, 111, 2929–2935; b) R. A. McClelland, V. M. Kana-
gasabapathy, N. S. Banait, S. Steenken, J. Am. Chem. Soc.
1992, 114, 1816–1823; c) R. A. McClelland, in: Reactive Inter-
mediate Chemistry (Eds.: R. A. Moss, M. S. Platz, M.
Jones Jr.), Wiley-Interscience, Hoboken, NJ, 2004, pp. 3–40.
a) J. Bartl, S. Steenken, H. Mayr, R. A. McClelland, J. Am.
Chem. Soc. 1990, 112, 6918–6928; b) J. Bartl, S. Steenken, H.
We thank Dr. Thomas Ruppert for preliminary studies on the reac-
tions of amines with quinone methides. We are grateful to the
Deutsche Forschungsgemeinschaft (DFG) and the Fonds der
Chemischen Industrie for financial support.
[10]
[1] a) W. P. Jencks, M. Gilchrist, J. Am. Chem. Soc. 1968, 90, 2622–
2637; b) B. Schreiber, H. Martinek, P. Wolschann, P. Schuster,
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