Vol. 24, No. 2, 2013
Sodré et al.
217
organic layer was separated and evaporated to give the
pure 2-halostyrene.
(E)-2-Bromo-p-chlorostyrene
1H NMR (200 MHz, CDCl3) d 6.79-6.72 (d, 1H,
J 14.01 Hz), 7.09-7.02 (d, 1H, J 14.03 Hz), 7.32-7.19 (m,
4H); 13C NMR (50 MHz, CDCl3) d 107.4, 127.5, 129.2,
134.3, 134.6, 136.2; MS (70 eV) m/z 220 (M+ + 4), 218
(M+ + 2), 216 (M+), 137 (100%), 102, 101, 75.
(E)-2-Chlorostyrene
1H NMR (200 MHz, CDCl3) d 6.66-6.60 (d, 1H,
J 13.67 Hz), 6.87-6.80 (d, 1H, J 13.67 Hz), 7.25-7.33 (m,
10H); 13C NMR (50 MHz, CDCl3) d 118.9, 126.3, 128.4,
129.0, 133.5, 135; MS (70 eV) m/z 140 (M+ + 2), 138 (M+),
103 (100%), 77, 51.
Computational details
All calculations were carried out using the B3LYP
functional and 6-31++G** basis set. Minima on the
potential energy surface were characterized by absence
of the harmonic frequencies of the respective optimized
structures, while the transition state presents a single
imaginary frequency after vibrational analysis. Further
IRC analysis confirmed that the transition state connects
the π-complex to the final decarboxylated products. All
energy differences correspond to enthalpy differences at
298.15 K and 1 atm. The calculations include solvation
using the IEFPCM(H2O) model.21 All calculations were
carried out using the Gaussian 09 package.22
(E)-2-Bromostyrene
1H NMR (200 MHz, CDCl3) d 6.72-6.79 (d, 1H,
J 13,99 Hz), 7.06-7.13 (d, 1H, J 13,99 Hz), 7.29 (m, 5H);
13C NMR (50 MHz, CDCl3) d 106.7, 126.3, 128.5, 129.0,
136.1, 137.4; MS (70 eV) m/z 184 (M+ + 2), 182 (M+), 103
(100%), 77, 51.
(E)-2-Chloro-p-methoxystyrene
1H NMR (200 MHz, CDCl3) d 3.77 (s, 3H), 6.50-6.43
(d, 1H, J 13.62 Hz), 6.78-6.71 (d, 1H, J 13.67 Hz),
6.85-6.81 (d, 2H), 7.22-7.17 (d, 2H); 13C NMR (50 MHz,
CDCl3) d 55.4, 114.4, 116.5, 127.5, 127.8, 132.9, 159,8; MS
(70 eV) m/z 170 (M+ + 2), 168 (M+, 100%), 153, 125, 89.
Acknowledgments
(E)-2-Bromo-p-methoxystyrene
The authors thank the Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq) and
the Fundação de Amparo à Pesquisa do Estado do Rio de
Janeiro (FAPERJ) for financial support. L. R. S. thanks
PIBIC/UFRJ and FAPERJ for fellowships.
1H NMR (200 MHz, CDCl3) d 3.80 (s, 3H), 6.63-6.56
(d, 1H, J 13.94 Hz), 6.87-6.83 (d, 2H), 7.07-7.00 (d, 1H,
J 13.95 Hz), 7.25-7.20 (d, 2H); 13C NMR (50 MHz, CDCl3)
d 55.5, 104.2, 114.4, 127.6, 129.0, 136.8, 159.9; MS (70 eV)
m/z 214 (M+ + 2), 212 (M+, 100%), 199, 197, 133, 118, 90.
References
(E)-2-Chloro-p-methylstyrene
1H NMR (200 MHz, CDCl3) d 2.33 (s, 3H), 6.60-6.54
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7.24-7.09 (m, 4H); 13C NMR (50 MHz, CDCl3) d 21.4,
117.9, 126.2, 129.7, 132.3, 133.3, 138.3; MS (70 eV) m/z
154 (M+ + 2), 152 (M+), 117 (100%), 115, 91.
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