5582 J . Org. Chem., Vol. 62, No. 16, 1997
Nakamura et al.
Tr a p p in g Exp er im en ts. A solution of 1 (0.040 M) and 2
2-(2-ter t-Bu toxy-1-p h en yleth oxy)-1,1,3,3-tetr a m eth yl-
2,3-d ih yd r o-1H-isoin d ole (6a ):13 δC (CDCl3) 145.6, 145.3,
142.2, 128.1, 127.8, 127.7, 127.0, 121.6, 121.4, 88.9, 73.1, 68.4,
66.9, 65.6, 29.5, 29.4, 27.6, 25.4; m/z 390 (M + Na)+, 368 (M +
H)+.
2-[2-(ter t-P en tyloxy)-1-ph en yleth oxy]-1,1,3,3-tetr am eth -
yl-2,3-d ih yd r o-1H-isoin d ole (6b): δH (CDCl3) 7.44-6.94
(9H), 4.87 (dd, J ) 8.4, 4.1 Hz, 1H), 3.78 (dd, J ) 10.0, 8.4 Hz,
1H), 3.38 (dd, J ) 10.0, 4.1 Hz, 1H), 1.52 (q, J ) 7.5 Hz, 2H),
1.69 (s, 3H), 1.51 (s, 3H), 1.26 (s, 3H), 1.16 (s, 3H), 1.15 (s,
3H), 0.88 (t, J ) 7.5 Hz, 3H), 0.77 (s, 3H); δC (CDCl3) 145.6,
145.3, 142.3, 128.0, 127.8, 127.7, 127.0, 121.6, 121.4, 88.7, 75.1,
68.3, 66.9, 65.1, 33.0, 29.6, 29.4, 25.3, 25.0, 24.8, 8.4; m/z 404
(M + Na)+, 382 (M + H)+.
2-[2-(ter t-Hexyloxy)-1-ph en yleth oxy]-1,1,3,3-tetr a m eth -
yl-2,3-d ih yd r o-1H-isoin d ole (6c): δH (CDCl3) 7.45-6.94
(9H), 4.87 (dd, J ) 8.4, 4.1 Hz 1H), 3.80 (dd, J ) 10.0, 8.4 Hz,
1H), 3.40 (dd, J ) 10.0, 4.1 Hz, 1H), 1.70 (s, 3H), 1.52 (s, 3H),
1.50-1.24 (m, 4H), 1.28 (s, 3H), 1.18 (s, 3H), 1.16 (s, 3H), 0.91
(t, J ) 7.0 Hz, 3H), 0.78 (s, 3H); δC (CDCl3) 145.6, 145.4, 142.3,
128.1, 127.9, 127.7, 127.6, 127.1, 121.7, 121.4, 88.7, 75.0, 68.4,
66.9, 65.1, 43.1, 29.6, 29.4, 25.5, 25.3, 17.3, 14.8; m/z 418 (M
+ Na)+, 396 (M + H)+.
2-(1-P h en ylb u t oxy)-1,1,3,3-t et r a m et h yl-2,3-d ih yd r o-
1H-isoin d ole (10b): δH (CDCl3) 7.40-6.94 (9H), 4.68 (dd, J
) 8.1, 6.1 Hz, 1H), 2.21-2.03 (m, 1H), 1.86-1.67 (m, 1H), 1.5-
1.2 (m, 2H), 1.63 (s, 3H), 1.45 (s, 3H), 1.24 (s, 3H), 0.94 (t, J )
7.3 Hz, 3H), 0.72 (s, 3H); δC (CDCl3) 145.5, 145.2, 143.9, 128.0,
127.7, 127.4, 127.1, 127.0, 121.7, 121.3, 88.0, 68.0, 66.9, 38.3,
30.2, 29.3, 25.7, 25.2, 19.5, 14.2; m/z 346 (M + Na)+, 324 (M +
H)+.
(0.040 M) in freshly distilled styrene was degassed by three
successive freeze-pump-thaw cycles to 10-4 mmHg).
A
relatively low concentration of 2 was used in order to study
the competitive reaction of alkyl radicals with styrene. How-
ever, under the conditions of the reaction, 2 is still present in
excess because of the low conversion (<15%) and the <100%
efficiency of generation of radicals from 1.12 The reaction
vessel was then sealed under vacuum and heated at 60 ( 0.1
°C for 1.0 h. The majority (ca. 90%) of excess monomer was
then removed under reduced pressure prior to analysis by
reversed-phase HPLC with methanol/water mixtures as the
eluent. The HPLC-separated products were identified by
electrospray mass spectrometry. Products 4, 7, 8, 9b,c, and
11 were also identified by cochromatography with authentic
samples. New compounds were isolated by preparative HPLC
and characterized by NMR.
P r od u ct An a lysis. Analytical HPLC studies were carried
out with a Shimadzu LC-9A liquid chromatograph fitted with
either a Waters Nova-Pak C18 6 mm, 100 × 8 mm ODS
analytical column or a Rainin Instruments Dynamax-60A 8
mm 250 × 4.6 mm C18 analytical column, connected to a
Shimadzu UV spectrophotometric detector set at 270 nm and
a CR-6A computing integrator.
Peak areas were determined by integration of HPLC chro-
matograms. Allowance for differing chromophores was made
either by determining the extinction coefficients at 270 nm of
the isolated products or by the reinjection of solutions of known
concentration to assess peak response ratios for the UV
detector. The adjusted peak areas were converted into relative
product yields and normalized to 100%.
The reaction products were isolated using preparative
reversed-phase HPLC on a Rainin Instruments Dynamax-60A
8 µm 250 × 21.4 mm C18 preparative column. Compounds
were detected by a Soma UV detector S-310A fitted with a 1.0
mm preparative cell. Solvent flow rates were variable depend-
ing upon the methanol-water ratio and the back pressure,
which was kept less than 2500 psi by a Gilson 303 pump fitted
with a 25 cm3 min-1 preparative head and 803C manometric
module.
NMR spectra were recorded on a Varian Gemini-200 (200
MHz) spectrometer, using deuterated chloroform as solvent.
Chemical shifts for 1H NMR spectra are relative to residual
CHCl3 (δ 7.24 ppm) and for 13C NMR spectra are relative to
the central peak of the triplet resonance due to CDCl3 (δ 77.0
ppm).
2-[(1-P h en ylpen tyl)oxy]-1,1,3,3-tetr am eth yl-2,3-dih ydr o-
1H-isoin d ole (10c): δH (CDCl3) 7.40-6.94 (9H), 4.66 (dd, J
) 8.2, 6.1 Hz, 1H), 2.24-2.04 (m, 1H), 1.88-1.68 (m, 1H), 1.63
(s, 3H), 1.5-1.1 (m, 4H), 1.45 (s, 3H), 1.23 (s, 3H), 0.89 (t, J )
7.0 Hz, 3H), 0.72 (s, 3H); δC (CDCl3) 145.5, 145.1, 144.0, 128.0,
127.7, 127.4, 127.1, 127.0, 121.7, 121.4, 88.2, 68.0, 67.0, 35.7,
30.2, 29.3, 28.4, 25.7, 25.2, 22.9, 14.1; m/z 360 (M + Na)+, 338
(M + H)+.
2-[(6-H yd r oxy-6-m et h yl-1-p h en ylh ep t yl)oxy]-1,1,3,3-
tetr a m eth yl-2,3-d ih yd r o-1H-isoin d ole (12): δH (CDCl3)
7.40-6.94 (9H), 4.66 (dd, J ) 8.2, 6.2 Hz, 1H), 2.24-2.04 (m,
1H), 1.88-1.68 (m, 1H), 1.63 (s, 3H), 1.6-1.1 (m, 6H), 1.45 (s,
3H), 1.23 (s, 3H), 1.20 (s, 6H), 0.73 (s, 3H); δC (CDCl3) 145.4,
145.1, 143.8, 128.0, 127.7, 127.5, 127.1, 127.0, 121.7, 121.4,
88.2, 71.0, 68.0, 67.0, 43.9, 36.0, 30.3, 29.3, 26.8, 25.7, 25.3,
24.5; m/z 418 (M + Na)+, 396 (M + H)+.
HPLC-electrospray mass spectra were obtained with a
single quadrupole VG Platform II mass spectrometer, coupled
to a MassLynx data system.
Rea ction of ter t-Bu toxyl Ra d ica ls w ith Styr en e in th e
P r esen ce of 2. The reaction of di-tert-butyl peroxyoxalate
(0.040 M) with styrene in the presence of 2 (0.090 M)
was carried out at 60 °C for 1.5 h in the same manner as
above.
The new compounds and a known compound 6a (13C NMR
data not previously reported) were isolated by preparative
HPLC and characterized by the NMR data listed below.
2-(3,3-Dim et h yl-1-p h en ylb u t oxy)-1,1,3,3-t et r a m et h yl-
2,3-d ih yd r o-1H-isoin d ole (5): δH (CDCl3) 7.44-6.92 (9H),
4.73 (dd, J ) 10.4, 3.3 Hz, 1H), 2.18 (dd, J ) 13.6, 3.3 Hz,
1H), 1.96 (dd, J ) 13.6, 10.4 Hz, 1H), 1.65 (s, 3H), 1.43 (s,
3H), 1.18 (s, 3H), 0.82 (s, 9H), 0.64 (s, 3H); δC (CDCl3) 145.6,
145.1, 144.7, 129.0, 127.9, 127.6, 127.1, 121.7, 121.4, 85.6, 67.9,
66.9, 48.8, 30.6, 30.4, 29.1, 25.9, 25.3; m/z 374 (M + Na)+, 352
(M + H)+.
Ack n ow led gm en t. We thank NOF Corporation,
Griffith University, and the Australian Research Coun-
cil for financial assistance.
J O9707489