Copper(II) Triflate as a Source of Triflic Acid
FULL PAPERS
strong acids (TfOH, Tf2NH, …) were used as catalysts, they
were added at the very end to the reaction mixture under
vigorous stirring to avoid the formation of polymer. Then,
the reaction mixture was vigorously stirred and heated at
0.4 mL) and added over degassed DCPD (1.1ꢂ10À4 mol,
15.0 mg) or degassed NB (1.1ꢂ10À4 mol, 10.0 mg) in a ESR
tube. The mixture was heated to 708C for the given time
period and EPR spectra were recorded at room tempera-
ture.
1
1008C. The conversion was determined by H NMR analysis
of aliquots sampled over regular time periods. When the re-
action was completed, the mixture was cooled to room tem-
1
perature and analyzed by H NMR and GC-MS. The crude
reaction mixture was diluted in pentane (ca. 50 mL) and
washed with 1M aqueous NaOH. The organic layer was
dried over MgSO4 and filtered through celite. Volatiles were
removed under vacuum to give impure DCPOMA as a
brown oil (yield: ca. 90%). This crude product was purified
by column chromatography on silica gel (heptane/ethyl ace-
tate: 6/1; Rf =0.75) to give DCPOMA as a pale yellow oil
(isolated yield: 85%).
Acknowledgements
This work was gratefully supported by Total Co. (post-doc
grant to MT).
References
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DCPOMA
1H NMR (500 MHz, 258C, CDCl3): d=6.15 (s, 1H, H-15),
5.89 (m, 1H, H-5), 5.59 (s, 1H, H-15), 5.47 (m, 1H, H-4),
3
4.28 (br t, J=5 Hz, 2H, H-12), 3.66 (m, 2H, H-11), 3.46 (m,
1H, H-8), 2.70–2.40 (m, 2H, H-3, H-6), 2.2–1.8 (m, 4H, H-1,
H-2, H-3, H-7), 1.96 (s, 3H, H-16), 1.8–1.55 (m, 1H, H-9),
1.45–1.10 (m, 3H, H-9, H-10); 13C NMR (125 MHz, 258C,
CDCl3): d=167.40, 136.25, 132.49, 132.13, 132.12 131.15,
126.61, 82.80 , 82.15 , 66.19 , 66.15 , 64.09, 55.24, 51.28,
47.62, 44.97, 43.10, 41.70, 39.28, 39.25, 39.16, 28.41, 28.31,
18.32; MS (EI): m/z=224 (M+).
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exo-NBOMA
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1H NMR (500 MHz, 258C, CDCl3): d=6.13 (s, 1H, H-12),
3
5.57 (m, 1H, H-12), 4.26 (t, J=5 Hz, 2H, H-9), 3.63 (m,
3
3
2H, H-8), 3.39 (d, J=6.8 Hz,1H, H-1), 2.32 (d, J=4.7 Hz,
1H, H-4), 2.23 (br. s, 1H, H-7), 1.95 (s, 3H, H-13), 1.60–1.35
(m, 5H, H-3, H-5, H-6, H-2), 1.12–0.92 (m, 3H, H-5, H-6,
H-7); 13C NMR (125 MHz, 258C, CDCl3): d=167.37 (C-10),
136.25 (C-11), 125.58 (C-12), 82.84 (C-1), 65.96 (C-9), 64.09
(C-8), 40.35 (C-4), 39.49 (C-7), 35.12 (C-2), 34.83 (C-3),
28.53 (C-5), 24.51 (C-6), 18.31 (C1-3); MS (EI): m/z=262
(M+).
For experiments conducted in the presence of phenylhy-
drazine, the latter reagent was added directly onto solid Cu-
ACHTUNGTRENNUNG(OTf)2. The resulting brown solid was mixed for ten mi-
nutes, and then NB and HEMA were added. The reaction
mixture was vigorously stirred for 2 h at room temperature
and then heated at 1008C.
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ESR Studies
In a typical experiment, in the glove box, Cu
ACHTUNGRTENN(UNG OTf)2 (2.7ꢂ
10À5 mol, 10.0 mg) was dissolved in degassed CH3CN (ca.
Adv. Synth. Catal. 2009, 351, 2496 – 2504
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2503