small pieces were added to 250 mL of distilled ammonia until
no more solid was present, the Ph2Pꢀ ions now being ready for
use (orange solution), and t-BuOH (1 mmol) was added
to neutralize the amide ions formed. The substrate exo-2-
bromonorbornane (1 mmol) was added to the solution and
the reaction mixture irradiated. Next, the reaction was
quenched with an excess of methyl iodide and the ammonia
allowed to evaporate. The residue was dissolved in water and
then extracted with diethyl ether. The products were isolated
by column chromatography. In the other experiments, the
products were quantified by GLC using the internal standard
method.
128.44, 128.45, 128.52, 128.57, 128.62, 130.57 (d), 130.88,
130.91, 130.95, 130.97, 131.00, 131.03, 131.26, 131.29, 131.32,
131.34, 131.39 (d), 132.03 (d), 134.0 (d). endo—1H-NMR
d 1.21–1.32 (m, 2H), 1.34–1.40 (m, 1H), 1.48–1.53 (m, 2H),
1.68–1.77 (m, 2H), 2.27–2.31 (m, 1H), 2.35–2.39 (b, 1H),
2.36–2.40 (b, 1H), 2.55–2.60 (m, 1H) 7.52–7.39 (m, 6H)
7.70–7.84 (m, 4H). 13C-NMR d 25.23 (d), 29.21, 30.16, 37.58
(CH, d), 39.52 (d), 39.57, 41.28 (d). HRMS [MH]+ calc. for
C19H21OP 297.1408; found: 297.1407.
2-Norborylphenylsulfide (2). exo—GC-MS (EI+) m/z (%):
206 (2), 205 (4), 204 (M+) (33), 110 (24), 109 (8), 96 (9), 95
(100), 79 (14), 67 (34), 65 (11). endo— GC-MS (EI+) m/z (%):
206 (1), 205 (3), 204 (M+) (20), 110 (20), 109 (6), 96 (7), 95
(100), 79 (6), 67 (29), 65 (9). exo—1H-NMR d 1.03 (ddd
J1 = 2, J2 = 6, J3 = 12, 1H), 1.22–1.31 (m, 1H), 1.33–1.42
(m, 1H), 1.40–1.44 (t, J = 1.91 2H), 1.50–1.59 (m, 1H),
1.96–2.05 (m, 1H), 2.08–2.17 (m, 1H), 2.28 (t, J = 4.35,
1H), 2.38 (t, J = 2, 1H), 3.51–3.59 (m, 1H), 7,14 (tt, J1 = 2,
J2 = 7, 1H), 7.22–7.29 (m, 2H), 7.32 (ddd, J1 = 1.2, J2 = 9,
2H). 13C-NMR: d 23.23, 29.81, 37.04, 38.16, 39.15, 40.84,
47.83, 125.52, 128.74, 129.53, 137.60. endo—1H-NMR:
d 1.12–1.32 (m, 1H), 1.32–1.47 (m, 3H), 1.48–1.64 (m, 1H),
1.65–1.74 (m, 1H), 1.76–1.84 (m, 1H), 2.30 (b, 1H), 2.32 (b,
1H), 3.16–3.22 (m, 1H), 7.14 (m, 1H), 7.22–7.29 (m, 2H), 7.32
(m, 2H). 13C-NMR: d 28.70, 28.91, 35.61, 36.52, 38.63, 42.33,
48.16, 125.52, 128.78, 128.97, 137.60. HRMS [MH]+ calc.
C13H16S 205.1021; found: 205.1046.
Photostimulated reactions of endo- and exo-3-chloro-2-
norbornanone with PhSꢀ ions in liquid ammonia. The following
procedure is representative of these reactions. PhSH (5 mmol)
and t-BuOH (5.1 mmol) were added to 250 mL of distilled
ammonia, the PhSꢀ ions now being ready for use. The
substrates endo- and exo-3-chloro-2-norbornanone (1 mmol)
were added to the solution, and the reaction mixture irradiated.
Next, the reaction was quenched with an excess of methyl
iodide and the ammonia allowed to evaporate. The residue
was dissolved in water and then extracted with diethyl ether.
The products were isolated by column chromatography. In the
other experiments, the products were quantified by GLC using
the internal standard method.
Photostimulated reactions of endo- and exo-3-chloro-2-
norbornanone with PhSꢀ ions in DMSO. The following procedure
is representative of these reactions. To 5 mL of dry and de-gassed
DMSO under nitrogen were added t-BuOK (5.1 mmol) and
PhSH (5 mmol). After 15 min, endo- and exo-3-chloro-2-
norbornanone (1.0 mmol) were added and the reaction mixture
irradiated. The reaction was quenched with an excess of methyl
iodide. The residue was dissolved in water and then extracted
with diethyl ether. Finally, HNO3 was added to the water phase
up to pH 5–6. The water phase was then extracted with diethyl
ether. The products were isolated by column chromatography. In
similar experiments, the products were quantified by GLC using
the internal standard method.
1,7,7-Trimethyl-3-(phenylthio)bicyclo[2.2.1]heptan-2-one (7).
exo—GC-MS (EI+) m/z (%): 260 (M+) (34), 232 (5), 149
(100), 123 (35), 116 (16), 83 (8), 81 (11). endo—GC-MS (EI+)
m/z (%): 260 (44), 232 (6), 150 (11), 149 (100), 147 (11), 134
(5), 123 (37), 116 (16), 115 (10), 109 (6), 81 (12), 65 (6), 55 (12).
endo—1H-NMR: d 0.92 (s, 3H), 0.96 (s, 3H), 1.03 (s, 3H), 1.7
(m, 4H), 2.0 (m, 1H), 2.28 (m, 1H), 3.92 (d, 1H), 7.33–7.17 (m,
3H), 7.43–7.56 (m, 2H). 13C-NMR d 9.68, 19.37, 19.67, 21.47,
30.81, 46.03, 48.66, 56.75, 58.64, 126.87, 130.06 (2C), 130.93
(2C), 135.72, 215.94. exo—1H-NMR d 0.96 (s, 3H), 0.98 (s,
3H), 1.02 (s, 3H), 1.7 (m, 4H), 2.0 (m, 1H), 2.28 (m, 1H), 3.33
(d, 1H), 7.17–7.33 (m, 3H), 7.43–7.56 (m, 2H). 13C-NMR d
9.57, 19.37, 19.83, 21.51, 30.92, 46.7, 51.3, 57.71, 58.06, 126.57,
128.97 (2C), 130.10 (2C), 135.77, 216.89. HRMS [MH]+ calc.
for C16H20OS 261.1313; found: 261.1308.
Reactions in the dark. The procedure was similar to that for
the previous reaction, except that the reaction flask was
wrapped with aluminium foil prior to substrate addition.
Inhibited reactions. The procedure was similar to that for the
previous reaction, except that 20 mol% of p-DNB was added
to the solution of nucleophile prior to substrate addition.
Computational procedures
These calculations were performed using Gaussian 03.15 The
characterization of stationary points was performed by
Hessian matrix calculations. Exploration of the potential
surface was carried out within the functional B3LYP,12 and
varying the selected coordinate with full optimization for the
remaining degrees of freedom.
Isolation and identification of the products
2-Norbornyldiphenylphosphine oxide (1). exo—GC-MS
(EI+) m/z (%): 296 (24), 295 (61), 230 (15), 229 (100), 202
(60), 201 (29), 155 (19), 125 (8), 77 (18). endo—GC-MS (EI+)
m/z (%): 296 (39), 295 (15), 230 (18), 229 (100), 202 (89), 201
(23), 155 (14), 125 (8), 77 (16). exo—1H-NMR (400.16 MHz,
CDCl3, 25 1C): d 1.17 (d, J = 9.8, 1H), 1.23–1.33 (m, 2H),
1.54–1.62 (m, 2H), 1.82–1.88 (m, 1H), 1.88–2.00 (m, 1H), 2.29
(t, J = 7.7, 1H), 2.34–2.37 (b, 1H), 2.49 (b, 1H), 7.52–7.39 (m,
6H) 7.70–7.84 (m, 4H). 13C-NMR d 28.67, 31.42 (d), 32.13 (d),
36.44 (CH, d), 37.30, 38.15, 39.89. exo and endo—128.41,
Acknowledgements
This work was supported in part by ACC, CONICET,
SECYT and ANPCyT. J. G. U. gratefully acknowledges
receipt of a fellowship from CONICET.
ꢁc
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2010 New J. Chem., 2010, 34, 2006–2012 | 2011