7.71-7.69 (2H, m, ArH), 7.41-7.35 (3H, m, ArH), 6.34 (1H, dd, J6,5 5.8Hz, J6,7 3.0Hz,
H6) 6.08 (1H, dd, J5,6 5.5Hz, J5,4 3.2Hz, H5), 5.40 (2H, m, H2,3(t)), 5.34 (2H, m,
H2,3(c)), 5.18 (1H, m, H6 isoxazoline), 4.97 (1H, dd, J7a71.2Hz, J7a3a 8.2Hz, H7a), 3.86 (1H,
m, H5 isoxazoline), 3.76 (1H, dd, J3a7a 8.2Hz, J3a4 0.6Hz, H3a), 3.26 (1H, d, J77a 1.3Hz, H7),
3.14 (1H, d, J43a 0.6Hz, H4), 2.96 (2H, m, H1,4(c)), 2.71 (2H, m, H1,4(t)) ,1.99 (1H, m,
H7’(c/t)), 1.63 (2H, s H8,), 1.14 (1H, m, H7’(c/t)); C 159.0 (C5a
isoxazoline),
155.6 (C3),
139.8 (PhCH), 135.2 (PhCH), 134.8 (C2,3(c/t)), 133.8 (C2,3(cc)), 132.6 (C2,3(tt)), 123.3
(C2,3(tc)), 129.6 (PhCH), 128.9 (PhC), 128.5 (C6), 126.4 (C5), 89.2 (C7a), 87.3
(C6isoxazoline), 57.4 (C3a), 50.1 (C5 isoxazoline), 49.7 (C7), 48.6 (C1,4(tc)), 48.2 (C1,4(tt)), 47.6
(C7(cc)), 46.6 (C7(tc/ct)), 45.6 (C7(tt)), 44.9 (C4), 42.9 (C8), 38.7 (C7(cc)), 35.3 (C7(c/t)),
35.1(C7(tt)).
(Polymeric isoxazoline shifts in bold)
3.6.2.2
R.O.M.P. of exo-3-Phenyl-3a,4,7,7a-tetrahydro-4,7methano-benzo[d]isoxazole (50)
Exo-3-Phenyl-3a,4,7,7a-tetrahydro-4,7-methano-benzo[d]isoxazole (32) was used for
ROMP as described above though no hex-1-ene was used. The product was afforded
as a grey polymeric solid, yield 0.13g, (87%), H (200MHz, CDCl3), 7.70 (2H, m,
ArH), 7.36 (3H, m, ArH), 5.50 (2H, m, H2,3), 4.82 (1H, m, H6isoxazoline), 3.81 (1H, m,
H5isoxazoline), 2.70 (2H, m, H 1.4), 1.90 (1H, m, H 7'(c/t)), 1.62 (2H, m, H5,6), 1.26 (1H, m,
H7(c/t)).
C - Unable to interpret spectra.
3.6.3
R.O.M.P.
of
3-ethoxycarbonyl-3a,4,7,7a-tetrahydro-4,7-
methano-benzo[d]isoxazole (51)
3-ethoxycarbonyl-3a,4,7,7a-tetrahydro-4,7-methano-benzo[d]isoxazole (34) and 10%
hex-1-ene were used for ROMP as described above, yielding a non-viscous brown oil,
yield 0.094 g,(62.7%), H (200MHz, CDCl3) 6.28 (1H, dd, J6,55.8Hz, J6,73.0Hz, H6),
6.07 (2H, m, H2,3(t)), 6.02 (2H, m, H2,3(c)), 6.00 (1H, dd, J5,65.7Hz, J5,43.2Hz, H5),
5.40 (1H, m, H6 isoxazoline) , 4.97 (1H, dd, J7a71.3Hz, J7a3a8.4Hz, H7a) 4.36-4.21 (2H, m,
OCH2CH3), 3.91 (1H, m, H5 isoxazoline), 3.53 (1H, dd, J3a7a8.3Hz, J3a40.6Hz, H3a), 3.41
(2H, m, H1,4(c)), 3.32 (2H, m, H1,4(t)), 3.25 (1H, d, J77a1.3Hz, H7), 3.20 (1H, d,
J43a0.6Hz, H4), 1.78 (1H, m, H7’(c/t)), 1.60 (2H, s H8,), 1.60 (2H, s, H8), 1.36-1.30 (2H,
m, OCH2CH3), 1.24 (1H, m, H7(c/t)); C 160.5 (CO2), 160.4 (CO2), 151.9(C5a), 150.9
(C3), 140.3 (C6), 135.7 (C2,3(t)), 134.9 (C2,3(c)), 134.6 (C5), 133.57 (C2,3(c)), 129.4
(C2,3(t)), 91.7 (C7a), 89.6 (C6 isoxazoline), 61.7 (OCH2CH3), 56.0 (C3a), 55.4 (C5 isoxazoline),
49.7 (C7), 46.8 (C1,4(tc)), 46.5 (C1,4(tt)), 46.3 (C1,4(cc)), 45.1 (C1,4(c/t)) 45.0, (C4), 42.7,
(C8), 35.9 (C7(cc)), 35.4 (C7'(tc/ct)), 35.3 (C7(tt)), 13.9 (OCH2CH3).
(Polymeric isoxazoline shifts in bold)
Softening temperatures of polymeric isoxazolines to be determined.
3.6.4
R.O.M.P of copolymer (52)
NMR data under review.
3.7
Ring opening of Isoxazolines
5
4
Ph
3
O
7
[H]
1
O
Cat.
HO
4
3
2
7a
N
3.7.1
3a
8
6
8
5
7
6
7a
Ring opening using Palladium on charcoal as catalyst (53)
3-phenyl-3a,4,5,6,7,7a-hexahydro-4,7-methano-benzo[d]isoxazole (28) (0.047 g, 0.19
mmol) and Boric acid (0.072 g, 1.16 mmol) were dissolved in methanol (15 ml) and
water (3 ml). 10% Palladium-on-charcoal (3 spatula tips) was added and the mixture
degassed using a water pump and hydrogen flushed five times, then left to stir
vigorously under a hydrogen atmosphere (H2 filled balloon) for 18h. The mixture was
filtered through cellite and evaporated in vacuo (no heating). Methanol was added and
evaporated several times to remove the excess boric acid as the volatile
trimethylborate. TLC analysis indicated the presence of unreacted isoxazoline and a
more polar component. The reaction was set up again with the same quantities of
reagents and left to stir vigorously for a further 20 h. Work up above afforded, after
preparative TLC (60% ether in hexane), unreacted isoxazoline which did not stain
with Brady’s reagent indicating the absence of the ketone.
NMR data (13CNMR) confirmed retrieval of starting material and most notably no
peak at approximately 210 ppm (C=O shift).
3.6.2
Ring opening using Raney nickel as catalyst (54)
3-Phenyl-3a,4,5,6,7,7a-hexahydro-4,7-methano-benzo[d]isoxazole (28) (0.011g, 0.05
mmol, 1 eq), Raney Ni (3 spatula tips) and boric acid (20 mg, 0.3 mmol, 6 eq) were
stirred in methanol (5 ml) and water (1 ml). THF (ca. 3 ml) was added dropwise until
the solid present dissolved. The solution was degassed with a water pump and flushed
several times with hydrogen before leaving to stir vigorously under a hydrogen
atmosphere (H2 filled balloon). The reaction was monitored by TLC and after all the
starting material had been consumed (ca. 24-48 hrs) the solution was filtered through
a celite pad and the solvent removed in vacuo. Methanol was added and evaporated
off several times to remove any remaining boric acid as the volatile trimethyl borate
ester. The product, which was obtained as an oil, was identified as mostly starting
material; however there were presence of some other peaks in the 13C NMR most
notably at 195 pmm which is in the vicinity for a carbonyl shift. IR spectroscopy
revealed a peak at 1679.4 cm-1 which is the frequency of a carbonyl stretch.