7426 J . Org. Chem., Vol. 66, No. 22, 2001
Allen et al.
due to 4 and the appearance of new absorptions at 2108 and
2124 cm-1 attributed to 2 (lit.2j 2117, 2128 cm-1; lit.2d 2149
cm-1, 12 K). Similar photolysis for 40 s of a 6 × 10-5 M solution
of 4 in isooctane led to the disappearance of the UV band of 4
at 395 nm and the formation of new bands due to 2 at 251 nm
(ꢀ ) 2.2 × 104) and 307 nm (ꢀ ) 5.6 × 103) assuming complete
conversion (lit.2i 250 nm, ꢀ ) 1.6 × 104 and 310 nm, ꢀ ) 5.4 ×
103).
Rea ction of 2 w ith TEMP O. A solution of 4 (52 mg, 0.31
mmol) in 30 mL of hexane and TEMPO (99 mg, 0.64 mmol)
was irradiated for 18 min with 300 and 350 nm lamps. The
solvent was evaporated, and 1H NMR analysis indicated the
presence of 4, 27, 28, and 29 in relative yields of 4, 14, 41,
and 41%, respectively. Chromatography (1/1 hexane/ether)
gave indenone 29 (81 mg, 0.26 mmol, 85%), which was
recrystallized from pentane/ether to give orange needles, mp
92-93 °C. 29: 1H NMR (CDCl3) δ 1.14 (s, 6, 2 CH3), 1.25 (s, 6,
2 CH3), 1.58-1.83 (m, 6, 3 CH2), 6.48 (s, 1, CdCH), 7.31-7.79
(m, 4, aryl); 13C NMR (CDCl3) δ 13.8, 17.7, 28.8, 36.0, 57.4,
120.3, 120.5, 126.6, 127.2, 127.3, 131.3, 139.0, 145.6, 160.2,
193.7; IR (CDCl3) 1744, 1716, 1604 cm-1; EIMS m/z 313 (M+,
0.7), 298 (16), 156 (100); HREIMS m/z calcd for C19H23NO3
313.1678, found 313.1685.
color that faded with time. The solvent was evaporated, and
the 1H NMR spectrum showed the presence of unreacted 14
and the product 31 in a 50/50 ratio. Chromatography (15/85
EtOAc/hexane) gave 31 (4 mg, 0.006 mmol, 32%): 1H NMR
(CD2Cl2, -20 °C) δ 0.26, 0.52, 0.58,1.06 (each s, 3, CH3), 1.2-
1.6 (m, 6, CH2), 5.99 (d, 1, J ) 7.8 Hz), 6.62 (t, 1, J ) 7.6, 7.3
Hz), 7.03 (t, 1, J ) 7.3 Hz), 7.32 (d, 1, J ) 7.3 Hz), 7.41, (t, 1,
J ) 7.3 Hz), 7.49 (t, 1, J ) 7.3 Hz), 7.61 (d, 1, J ) 7.3 Hz),
8.39 (d, 1, J ) 7.8 Hz); 13C NMR (CD2Cl2, -22 °C) δ 16.9 (CH2),
19.7 (CH3) 20.1 (CH3), 31.3 (CH3), 31.6 (CH3), 39.2 (CH2), 39.5
(CH2), 60.4, 60.8. 65.5, 118.7, 119.5, 125.7, 126.0, 126.7, 128.1,
128.9, 130.3, 141.3, 141.8, 142.6, 143.8, 171.8; IR (CDCl3) 1756
cm-1; UV λmax (hexane) 211 (ꢀ 7.3 × 104), 270 (ꢀ 2.7 × 104),
304 (ꢀ 4000); EIMS m/z 697 (0.2), 382 (14), 192 (15), 164 (17),
140 (100); HREIMS m/z calcd for C46H53N2O4 (MH+) 697.4005,
found 697.4015. A crystal was used for X-ray analysis.11
Rea ction of Di-ter t-bu tylfu lven on e 16 w ith TEMP O.
A solution of 15 (9 mg, 0.040 mmol) in 50 mL of hexane was
photolyzed with 300 and 350 nm light for 6 min, a solution of
TEMPO (26 mg, 0.17 mmol) in 0.04 mL hexane was added,
and the solution stirred overnight. The solvent was evaporated,
1
and H NMR examination revealed the presence of the fulvene
23 and a mixture of the dimers 24a and 24b. The product was
combined with another prepared from 15 (11 mg, 0.046 mmol)
and TEMPO (0.037 g, 0.24 mmol) and chromatographed with
CH2Cl2 to give 23 and a 37/63 mixture of 24a and 24b which
by HPLC (Porasil column, 99/1 hexanes/EtOAc) showed well-
resolved peaks at 9 and 10 min for 24b and 24a , respectively.
These were not isolated separately but were identified by their
spectral data. 24a : 1H NMR (CDCl3) δ 0.8-1.8 (m, CH3 and
CH2), 1.16 (s, 9, t-Bu), 1.25 (s, 9, t-Bu), 4.26 (d, 2, J ) 1.3 Hz,
CH), 6.22 (d, 2, 1.5 Hz); 13C NMR (CDCl3) δ 63.0, 129.4, 131.4,
152.2, 153.7, 170.2. 24b: 1H NMR (CDCl3) δ 1.17, 1.21, 1.23,
1.29 (each s, 9, t-Bu), 2.88 (d, 1, J ) 23.4 Hz, CHH), 3.04 (d,
1, J ) 23.6 Hz, CHH), 4.48 (d, 1, J ) 1.6 Hz, CH), 6.20 (d, J
) 1.6 Hz); 13C NMR (CDCl3) δ 44.3, 62.5, 129.7, 130.9, 132.6,
148.0, 149.4, 150.6, 154.4, 158.3, 167.4, 170.4; these peaks were
assigned by DEPT, COSY, HSQC, and HMBC, and others were
at δ 16.6, 16.8, 20.7, 21.5, 30 0, 30.9, 31.0, 31.2, 32.0, 32.3,
33.3, 34.0, 34.1, 34.2, 34.3, 34.5, 35.6, 39.2, 40.6, 59.9, 60.0,
60.3; IR (CDCl3) 1759, 1727 cm-1; UV λmax (pentane) 273 nm
(ꢀ ) 9900).
Kin etics of Rea ction s of 3 a n d 16 w ith TEMP O. A 1.9
× 10-3 M solution of 14 was irradiated for 1 min with 350 nm
light to form 3, 10 µL of this solution was injected into a
solution of TEMPO in isooctane ((3.76-17.6) × 10-5 M), and
the decrease in the absorption of 3 at 226 nm was observed.
Isosbestic points at 213, 248, and 257 nm were noted. The
second-order rate constant was obtained as the slope of a plot
of kobs vs [TEMPO]. A nonzero intercept due to reaction of 3
with H2O was observed, and this was confirmed by measuring
the rate constant for reaction of 3 in isooctane without TEMPO
and by observing the UV spectrum for the resulting acid from
this reaction.
A solution of 4 (11 mg, 0.064 mmol) in 50 mL of hexane
was irradiated with 350 nm light with stirring for 3 min to
form 2, and then TEMPO (20 mg, 0.13 mmol) in 50 µL hexane
was added and the solvent was evaporated at 15 °C. Analysis
by 1H NMR revealed the presence of 4, 27, 28, and 29 in
relative yields of 4, 74, 4, and 18%, respectively. Spectra of 27
were obtained from this and similar mixtures: 1H NMR
(CDCl3) δ 1.03 (s, 3, CH3), 1.10 (s, 3, CH3), 1.13 (s, 3, CH3),
1.17 (s, 3, CH3), 1.23 (s, 3, CH3), 1.26 (s, 3, CH3), 1.33 (s, 3,
CH3), 1.46 (s, 3, CH3), 1.5-1.8 (m, 12, 6 CH2), 5.51 (s, 1, CHO),
7.20-7.40 (m, 2, aryl), 7.60-7.63 (m, 2, 1 aryl H and 1 vinyl
H), 7.96 (d, 1, J ) 7 Hz, aryl H); 13C NMR (CDCl3) 17.5, 17.6,
20.6, 20.9, 21.2, 21.4, 32.4, 32.44, 34.5, 34.6, 39.5, 40.6, 59.9,
60.7, 61.8, 87.2, 123.1, 124.4, 126.8, 129.1, 133.2, 139.4, 143.3,
146.7, 164.3; the 1H and 13C signals of the carboxy indene
moiety were assigned by COSY, HMBC, and HSQC NMR
experiments as those from δ 87.2 and lower field; CIMS m/z
455 (0.2, MH+), 439, 411, 157 (54), 142 (100); HREIMS calcd
for C28H42N2O3 m/z 454.3195, found 454.3190. Addition of 1.4
µL of HOAc led to complete conversion of 27 to 29 on standing
overnight at 5 °C. Addition of Et3N (2 µL, 0.014 mmol) to a
similar mixture led to almost complete isomerization to 28:
1H NMR (CDCl3) δ 0.90, 0.92, 1.01, 1.02, 1.06, 1.09,1.26 1.28,
1.2-1.8 (m), 4.36 (s, 1, CHCO), 5.70 (s, 1, CdC), 7.15-7.70
(m, 4, aryl), plus Et3N peaks; 13C NMR (CDCl3) δ 17.6, 17.8,
20.9, 21.0, 21.1, 21.2, 32.4, 32.6, 33.4, 33.9, 39.7, 39.8, 40.4
(2), 51.4, 60.7, 60.8, 61.1, 61.2, 101.5, 118.9, 125.0, 126.6, 127.9,
139.3, 141.0, 162.3, 172.2. Using COSY and HSQC, the carbons
of the indenyl carboxy moiety were assigned as those at δ 51.4
and 101.5.
Kin etics of th e Rea ction of 2 w ith TEMP O. For each
run, 0.5 mL of a stock solution of 1.42 × 10-4 M 2 in isooctane
in a 1 mL UV cell was photolyzed for 40 s with 350 nm light
to form 2. Then 20 µL of this solution was injected into 2 mL
of a TEMPO solution in isooctane in a UV cell, the change in
the UV absorption was monitored at 250 nm, and isosbestic
points were observed at 206 and 234 nm. The plot of kobs versus
[TO•] gave a nonzero intercept attributed to reaction of 2 with
traces of moisture, as has been confirmed in another example.16
Rea ction of Diben zop en ta fu lven on e 3 w ith TEMP O.
A solution of 14 (8 mg, 0.038 mmol) in 50 mL of hexane was
photolzyed 100 s with 350 nm light, and TEMPO (6 mg, 0.038
mmol) in 0.03 mL hexane was added, giving an intense yellow
For the reaction of 16, 1.0 mL of a 2.6 × 10-4 M solution of
15 was irradiated for 4 min with 300 and 350 nm light, and
the resulting solution of 16 was concentrated to 0.08 mL. A
20 µL portion of this solution was injected into 2 mL of a
solution of TEMPO in isooctane, and the decrease in the
absorption of 16 at 270 nm or the increase at 310 nm was
monitored. Isosbestic points at 230 and 281 nm were noted.
Good first-order plots were observed.
Ack n ow led gm en t. Financial support by the Natu-
ral Sciences and Engineering Research Council of
Canada and the use of the ANALEST Laboratory
supported by Perkin-Elmer is gratefully acknowledged.
(17) Gaussian 94W, Revision E.1: Frisch, M. J .; Trucks, G. W.;
Schlegel, H. B.; Gill, P. M. W.; J ohnson, B. G.; Robb, M. A.; Cheeseman,
J . R.; Keith, T.; Petersson, G. A.; Montgomery, J . A.; Raghavachari;
K.; Al-Laham, M. A.; Zakrzewski, U. G.; Ortiz, J . V.; Foresman, J . B.;
Cioslowski, J .; Stefanov, B. B.; Nanayakkara, A.; Challacombe, M.;
Peng, C. Y.; Ayala, P. W.; Chen, W.; Wong, M. W.; Andres, J . L.;
Replogle, E. S.; Gomperts, R.; Martin, R. L.; Fox, D. J .; Binkley, J . S.;
Defrees, D. J .; Baker, J .; Stewart, J . P.; Head-Gordon, J .; Gonzales,
C.; Pople, J . A. Gaussian Inc., Pittsburgh, PA, 1995.
Su p p or tin g In for m a tion Ava ila ble: Experimental and
computational details, NMR spectra, and X-ray crystallo-
graphic data. This material is available free of charge via the
Internet at http://pubs.acs.org.
J O010601O