Stratakis et al.
7.22-7.35 (m, 5H), 6.96 (t, 1H, J ) 7.5 Hz), 3.76 (s, 3H), 3.56
(d, 2H, J ) 7.5 Hz), 1.99 (s, 3H). 3b: 7.21-7.34 (m, 5H), 6.84
(t, 1H, J ) 7.5 Hz), 3.76 (s, 3H), 2.78 (t, 2H, J ) 7.5 Hz), 2.52
(m, 2H), 1.81 (s, 3H). 3c: 7.19-7.32 (m, 5H), 6.81 (t, 1H, J )
7.5 Hz), 3.77 (s, 3H), 2.67 (t, 2H, J ) 8.0 Hz), 2.23 (m, 2H),
1.84 (s, 3H), 1.82 (m, 2H). 3d : 7.19-7.32 (m, 5H), 6.78 (t, 1H,
J ) 7.0 Hz), 3.76 (s, 3H), 2.67 (t, 2H, J ) 8.0 Hz), 2.23 (m,
2H), 1.85 (s, 3H), 1.68 (m, 2H), 1.52 (m, 2H). 3e: 6.82 (t, 1H,
J ) 7.0 Hz), 3.76 (s, 3H), 2.09 (t, 2H, J ) 7.0 Hz), 1.85 (s, 3H),
1.66-1.75 (m, 4H), 1.43 (m, 1H), 1.15-1.30 (m, 4H), 0.96 (m,
2H). 3f: 6.78 (t, 1H, J ) 7.0 Hz), 3.76 (s, 3H), 2.20 (m, 2H),
1.85 (s, 3H), 1.65-1.75 (m, 5H), 1.15-1.36 (m, 6H), 0.92 (m,
2H). 3g: 6.78 (t, 1H, J ) 7.0 Hz), 3.76 (s, 3H), 2.16 (m, 2H),
1.85 (s, 3H), 1.65-1.73 (m, 7H), 1.14-1.27 (m, 6H), 0.88 (m,
2H).
F IGURE 1. Conformational changes through the simulta-
neous coordination of the sodium ion with the phenyl group
and alkene double bond.
substituted substrates 6e-d , the coordination of the Na+
to the alkene double bond affords similar conformations
for the allylic methylene hydrogen atoms and, therefore,
they are approximately equally reactive. This is also
corroborated by the fact that the twix/ twin reactivity
ratio is the same for all cyclohexyl-substituted alkenes.
The change in the twix/ twin ratio with the remoteness
of the phenyl group in alkenes 6a -d is difficult to
rationalize. It certainly has to do with the conformational
changes of each specific alkene after confinement within
Na-Y.
In conclusion, we have presented in this study evidence
that cation-π interactions have conformational conse-
quences on the alignment of the allylic hydrogen atoms
for ene reaction. This coordination significantly influences
the regioselectivity of the dye-sensitized intrazeolite
photooxygenation of trisubstituted alkenes. The most
important finding is that a phenyl group at a remote
position with respect to the double bond can significantly
affect the regioselectivity of the intrazeolite singlet
oxygen ene reaction.
R ed u ct ion of r,â-Un sa t u r a t ed E st er s t o t h e Allylic
Alcoh ols-d 2 (4a -g). In a flame-dried, two-necked flask were
added 15.0 mmol of LiAlD4 and 15 mL of dry ether. The flask
was cooled to 0 °C, and 5.0 mmol of anhydrous AlCl3 was added
in portions. The resulting slurry was stirred for an additional
20 min, followed by the dropwise addition of the R,â-unsatur-
ated ester 3a -g (25.0 mmol). The reaction mixture was stirred
for 1-2 h and then treated with 2 mL of water. After extraction
with ether, the deuterated allylic alcohols were isolated in 85-
1
95% yield. The following are the H NMR data of the alcohols
4b-g. 4b: 7.22-7.33 (m, 5H), 5.49 (t, 1H, J ) 7.0 Hz), 2.70
(t, 2H, J ) 8.0 Hz), 2.39 (m, 2H), 1.65 (s, 3H), 1.45 (br. s., 1H).
4c: 7.20-7.32 (m, 5H), 5.46 (t, 1H, J ) 7.0 Hz), 2.66 (t, 2H, J
) 8.0 Hz), 2.11 (m, 2H), 1.73 (m, 2H), 1.68 (s, 3H), 1.45 (br. s.,
1H). 4d : 7.20-7.32 (m, 5H), 5.43 (t, 1H, J ) 7.0 Hz), 2.65 (t,
2H, J ) 8.0 Hz), 2.09 (m, 2H), 1.65 (s, 3H), 1.65 (m, 2H), 1.44
(m, 2H), 1.30 (br. s., 1H). 4e: 5.46 (t, 1H, J ) 7.5 Hz), 1.95 (t,
2H, J ) 7.0 Hz), 1.65-1.75 (m, 5H), 1.68 (s, 3H), 1.15-1.35
(m, 5H), 0.91 (m, 2H). 4f: 5.43 (t, 1H, J ) 7.5 Hz), 2.06 (m,
2H), 1.65-1.75 (m, 6H), 1.69 (s, 3H), 1.15-1.28 (m, 6H), 0.91
(m, 2H). 4g: 5.43 (t, 1H, J ) 7.0 Hz), 2.02 (m, 2H), 1.65-1.74
(m, 6H), 1.69 (s, 3H), 1.38 (m, 2H), 1.14-1.27 (m, 6H), 0.89
(m, 2H).
Mesyla tion of th e Allylic Alcoh ols-d 2 (5a -g). The allylic
alcohols-d2 4a -g (10.0 mmol) were placed into a flask charged
with 30.0 mmol of dry triethylamine and 30 mL of dry
dichloromethane. Subsequently, 11.0 mmol of methanesulfonyl
chloride was added dropwise at 0 °C. Immediate precipitation
of triethylammonium chloride was observed. After 25 min, the
solids were removed by filtration, and the organic layer was
washed with 5% HCl (until pH was acidic), then with saturated
solution of NaHCO3 (until pH was slightly basic), and finally
with 50 mL of brine. Prolonged reaction time leads to the
transformation of the initially formed mesylates to the corre-
sponding allylic chlorides. The allylic mesylates do not persist
and were used immediately in the next step without purifica-
tion. The following are the 1H NMR data of the mesylates 5a -
g. 5a : 7.19-7.33 (m, 5H), 5.84 (t, 1H, J ) 7.0 Hz), 3.44 (d,
2H, J ) 7.0 Hz), 3.00 (s, 3H), 1.68 (s, 3H). 5b: 7.21-7.34 (m,
5H), 5.68 (t, 1H, J ) 7.0 Hz), 2.95 (s, 3H), 2.73 (t, 2H, J ) 7.5
Hz), 2.44 (m, 2H), 1.70 (s, 3H). 5c: 7.19-7.32 (m, 5H), 5.66 (t,
1H, J ) 7.0 Hz), 3.02 (s, 3H), 2.65 (t, 2H, J ) 8.0 Hz), 2.13 (m,
2H), 1.74 (m, 2H), 1.73 (s, 3H). 5d : 7.17-7.30 (m, 5H), 5.62
(t, 1H, J ) 7.0 Hz), 2.99 (s, 3H), 2.61 (t, 2H, J ) 7.5 Hz), 2.10
(m, 2H), 1.72 (s, 3H), 1.65 (m, 2H), 1.43 (m, 2H). 5e: 5.67 (t,
1H, J ) 7.5 Hz), 3.02 (s, 3H), 1.98 (t, 2H, J ) 7.0 Hz), 1.74 (s,
3H), 1.65-1.75 (m, 5H), 1.15-1.35 (m, 4H), 0.94 (m, 2H). 5f:
5.63 (t, 1H, J ) 7.0 Hz), 3.01 (s, 3H), 2.08 (m, 2H), 1.74 (s,
3H), 1.65-1.75 (m, 5H), 1.15-1.35 (m, 6H), 0.90 (m, 2H).
Exp er im en ta l Section
Nuclear magnetic resonance spectra were obtained on a 500-
MHz instrument. Isomeric purities were determined by 1H
NMR and by GC analysis on a 60-m capillary column. All
spectra reported herein were taken in CDCl3.
The general procedures for the preparation of the labeled
alkenes 6a -g are as follows.
P r ep a r a tion of th e Ald eh yd es (2b-g). Except phenyl-
acetaldehyde (2a ), which is commercially available, the rest
of the aldehydes were prepared by pyridinium chlorochromate
(PCC) oxidation of the corresponding alcohols in 65-75% yield.
1
The following are the H NMR data of 2b-g. 2b: 9.86 (s, 1H),
7.22-7.34 (m, 5H), 2.99 (t, 2H, J ) 7.5 Hz), 2.82 (t, 2H, J )
7.5 Hz). 2c: 9.79 (s, 1H), 7.19-7.33 (m, 5H), 2.69 (t, 2H, J )
7.5 Hz), 2.48 (t, 2H, J ) 7.5 Hz), 2.01 (m, 2H). 2d : 9.78 (s,
1H), 7.20-7.34 (m, 5H), 2.68 (t, 2H, J ) 7.5 Hz), 2.49 (m, 2H),
1.71 (m, 4H). 2e: 9.86 (s, 1H), 2.30 (d, 2H, J ) 6.5 Hz), 1.00-
1.85 (m, 11 H). 2f: 9.77 (s, 1H), 2.44 (t, 2H, J ) 7.5 Hz), 1.63-
1.72 (m, 4H), 1.53 (m, 2H), 1.10-1.23 (m, 4H), 0.90 (m, 2H).
2g: 9.77 (d, 1H, J ) 1.2 Hz), 2.42 (dt, 2H, J 1 ) 7.0 Hz, J 2
)
1.2 Hz), 1.62-1.75 (m, 6H), 1.15-1.27 (m, 7H), 0.91 (m, 2H).
P r ep a r a tion of th e r,â-Un sa tu r a ted Ester s (3a -g). In
a one-necked flask were placed 80 mL of dry CH2Cl2 and 36.0
mmol of methyl(triphenylphosphoranylidene)propionate. Sub-
sequently, 30.0 mmol of the appropriate aldehyde was added
and the solution was stirred overnight. Most of the solvent
was removed by evaporation and then 50 mL of hexane was
added. The solid residue was washed with hexane (4 × 50 mL),
the hexane was evaporated, and the oily residue was distilled
at reduced pressure. The R,â-unsaturated esters were isolated
in 60-80% yield and in >92% purity of the E diastereomer.
The following are the 1H NMR data of the esters 3a -g. 3a :
P r ep a r a tion of th e Alk en es-d 3 (6a -g). The crude mesy-
lates 5a -g (10.0 mmol) dissolved in 5 mL of dry ether were
added dropwise at 0 °C to a flame-dried flask charged with a
suspension of 4.0 mmol of LiAlD4 and 10 mL of ether. The
reaction mixture was stirred overnight, during which the
mesylate had been transformed to the alkene-d3. After treat-
ment with 2 mL of water and extraction with ether, the
alkenes 6a -g were purified by flash silica gel chromatography
8762 J . Org. Chem., Vol. 67, No. 25, 2002