5440
A. P. da Silva et al. / Tetrahedron 62 (2006) 5435–5440
after each application. The anode should be polished before
electrolysis. For experiments involving Ni bpy as mediator,
Acknowledgements
0
II
the precursor [Ni (bpy)]Br was prepared separately accord-
2
We would like to acknowledge CNPq, FINEP/CTPETRO
and Petrobras for financial support.
2
2
ing to the literature. The electrolytic cell was charged un-
der nitrogen with 15.0 mL DMF containing NaI (4.0 mmol)
and 1,2-dibromoethane (1.4 mmol). A pre-electrolysis was
initiated under 150 mA constant current, during 30 min.
The substrate (1.5 mmol) was mixed with mediator
0.3 mmol) (FeSO , NiBr , and [Ni (bpy)]Br ) in 5.0 mL
References and notes
II
(
4
2
2
of solvent and then added to the cell. A 100 mA constant
current was applied until full consumption of the starting
reagent. The product yield was determined on a 0.5 mL
aliquot of the reaction solution. Water (2.0 mL) was added
to the aliquot and the products were extracted with 2.0 mL
of ethyl acetate (hexane for cyclohexene and 1,3-cyclohexa-
diene substrates) containing 0.067 mmol of toluene, used as
internal standard. The product yields were determined by
GC analysis. Toluene was used as internal standard to quan-
tify products and reagents. GC–MS analysis were obtained
with a Varian 3380 GC or Finnigan MAT-GCQ instrument,
fitted with a 30 m capillary CP-SPL5CB Chrompack col-
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ꢃ
ꢃ
ꢂ1
umn, using 60–200 C temperature range (20 C min ).
Comparisons with authentic sample were performed to iden-
tify hydrogenation products and reagents and confirmed by
GC–MS. Electrochemical efficiency of the process can be
calculated by equations relating current (I), time (t), charge
ꢂ
(
(
Q), electrons (e ) involved and mole number of hydrogen
n) promoted in the process: Q¼I (A)ꢁt (s)¼e ꢁnꢁF,
ꢂ
ꢂ1
where F¼96,487 C mol
.
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1
997, 185, 147.
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1
and 3ꢁ10.0 mL of diethyl ether. It was identified by H
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4.1. trans-5-Benzol[1,3]dioxol-5-yl-1-piperidin-1-yl-
pent-3-en-1-one [23512-55-2]
1
2. Caetano, V. F.; Demnitz, F. W. J.; Diniz, F. B.; Mariz, R. M., Jr.;
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1
H NMR (300 MHz, CDCl ): d 1.55 (m, J¼6.6 Hz, 4H),
3
1
.62 (m, J¼4.5 Hz, 2H), 3.20 (d, J¼5.1 Hz, 2H), 3.35 (d,
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J¼5.4 Hz, 2H), 3.30–3.60 (4H), 5.64 (m, 1H), 5.91 (s,
2
H), 6.64 (m, 1H), 6.67–6.74 (m, 3H). m/e 287 (53), 204
(
(
35), 174 (35), 152 (44), 135 (30), 112 (73), 84 (53), 69
100).
15. Durandetti, M.; Meignein, C.; P e´ richon, J. Org. Lett. 2003, 5,
3
17.
4.2. cis-5-Benzol[1,3]dioxol-5-yl-1-piperidin-1-yl-pent-
3-en-1-one
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8. Petrier, C.; Luche, J.-L. Tetrahedron Lett. 1987, 28, 2351.
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H NMR (300 MHz, CDCl ): d 1.55 (m, J¼6.6 Hz, 4H),
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3
1
.62 (m, J¼4.5 Hz, 2H), 3.12 (d, J¼6.3 Hz, 2H), 3.29 (d,
J¼3.9 Hz, 2H), 3.30–3.60 (4H), 5.63 (m, 1H), 5.91 (s,
2
H), 6.64 (m, 1H), 6.66–6.74 (m, 3H). m/e 287 (53), 204
(
(
35), 174 (35), 152 (44), 135 (30), 112 (73), 84 (53), 69
100).
22. Uchino, M.; Asagi, K.; Yamamoto, A.; Ikeda, S. J. Organomet.
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