4212 J . Org. Chem., Vol. 64, No. 11, 1999
Notes
Ta ble 2. Dea llyla tion of Ar yl Allyl Eth er s w ith
Electr ogen er a ted Nick el
carried out under an argon atmosphere at a constant current of
10 mA/cm2 at 0 °C until 965 coulombs of electricity had passed
to produce a black suspension containing the active nickel.
Gen er a l P r oced u r e for Dea llyla tion of Allyl Ar yl Eth er s.
The nickel-DMF suspension was added to an allyl aryl ether
(0.5 mmol) and NaOAc (2.5 mmol) using a syringe under an
argon atmosphere. The mixture was stirred for 18 h at room
temperature. Then 2 M HCl (10 mL) was added to the reaction
mixture. After the addition of Et2O (20 mL) to the solution, the
mixture was filtered through a Celite pad. The aqueous layer
was extracted with Et2O (10 mL × 3), and the ethereal layers
were combined. The ethereal layer was washed with H2O (20
mL × 3), dried over MgSO4, and evaporated under reduced
pressure. The residue was purified by recrystallization or
distillation.
Meth yl 4-h yd r oxyben zoa te (2a ): colorless needles from
Et2O-hexane; mp 124-125 °C (lit.7 mp 127 °C); 1H NMR (CDCl3/
TMS) δ 3.90 (s, 3 H), 6.77 (br, 1 H), 6.90 (d, J ) 8.8 Hz, 2 H),
7.95 (d, J ) 8.8 Hz, 2 H); IR ν (KBr) cm-1 3300, 1690; MS m/z
152 (M+).
Meth yl 3-h yd r oxyben zoa te (2b): colorless plates from
1
Et2O-hexane; mp 69-71 °C (lit.7 mp 73 °C); H NMR (CDCl3/
TMS) δ 3.92 (s, 3 H), 6.81 (br, 1 H), 7.07-7.11 (m, 1 H), 7.30 (t,
J ) 7.7 Hz, 1 H), 7.58-7.61 (m, 2H); IR ν (KBr) cm-1 3370, 1700;
MS m/z 152 (M+).
Meth yl 2-Hyd r oxyben zoa te (2c): colorless liquid; bp 40-
50 °C/3 mmHg (lit.7 mp 222 °C/760 mmHg); 1H NMR (CDCl3/
TMS) δ 3.95 (s, 3 H), 6.88 (dt, J ) 8.0, 1.1 Hz, 1 H), 6.98 (dd, J
) 1.1, 8.5 Hz, 1 H), 7.46 (ddd, J ) 8.5, 8.0, 1.6 Hz, 1 H), 7.84
(dd, J ) 8.0, 1.6 Hz, 1 H), 10.76 (s, 1 H); IR ν (KBr) cm-1 3200,
1680; MS m/z 152 (M+).
4-Hyd r oxyben zon itr ile (2d ): colorless plates from Et2O-
hexane; mp 109-110 °C (lit.7 mp 112 °C); 1H NMR (CDCl3/TMS)
δ 6.91 (d, J ) 8.2 Hz, 2 H), 7.55 (d, J ) 8.2 Hz, 2 H); IR ν (KBr)
cm-1 3290, 2230; MS m/z 119 (M+).
Sch em e 1. Dea llyla tion of P r im a r y a n d
Secon d a r y Allyloxy Su bstr a tes
4-Hyd r oxya cetop h en on e (2e): colorless prisms from Et2O-
hexane; mp 106-107 °C (lit.7 mp 110 °C); 1H NMR (CDCl3/TMS)
δ 2.57 (s, 3 H), 6.91 (d, J ) 8.8 Hz, 2 H), 7.91 (d, J ) 8.8 Hz,
2H); IR ν (KBr) cm-1 3310, 1660; MS m/z 136 (M+).
4-Hyd r oxyben za ld eh yd e (2f): colorless prisms from Et2O-
hexane; mp 110-112 °C (lit.7 mp 118 °C); 1H NMR (CDCl3/TMS)
δ 7.00 (d, J ) 8.5 Hz, 2 H), 7.83 (d, J ) 8.5 Hz, 2 H), 9.85 (s, 1
H); IR ν (KBr) cm-1 3170, 1670; MS m/z 122 (M+). Anal. Calcd
for C7H6O2: C, 68.85; H, 4.95. Found: C, 68.76; H, 5.05.
4-Ch lor op h en ol (2g): colorless viscous liquid; bp 50-60 °C/3
mmHg (lit.7 bp 220 °C/760 mmHg); 1H NMR (CDCl3/TMS) δ 5.81
(br, 1 H), 6.77 (d, J ) 8.8 Hz, 2 H), 7.18 (d, J ) 8.8 Hz, 2 H); IR
ν (KBr) cm-1 3340; MS m/z 128 (M+).
the electrogenerated nickel has a high reactivity for the
oxidative addition of the iodo group (Table 2, entry 2).
As for the deallylation of aliphatic allyoxy substrates, the
deprotection of primary (1o) and secondary (1p ) allyloxy
substrates with 8 equiv of electrogenerated nickel also
gave the corresponding alcohols in 69 and 70% yields,
although the deallylation with 4 equiv of nickel produced
low yields (37% and 57%, respectively) (Scheme 1).
In summary, the deallylation of the allyl aryl ethers
using a highly reactive nickel-DMF suspension, which
was easily prepared by electrolysis, proceeds in the
presence of NaOAc under mild conditions without affect-
ing the various functional groups.
4-Br om op h en ol (2h ): colorless prisms; mp 63-64 °C (lit.7
1
mp 66 °C); H NMR (CDCl3/TMS) δ 5.07 (br, 1 H), 6.73 (d, J )
8.8 Hz, 2 H), 7.34 (d, J ) 8.8 Hz, 2 H); IR ν (KBr) cm-1 3350;
MS m/z 172 (M+).
4-Iod op h en ol (2i): colorless prisms from Et2O-hexane; mp
91-93 °C (lit.7 mp 94 °C); 1H NMR (CDCl3/TMS) δ 5.09 (br, 1
H), 6.63 (d, J ) 8.8 Hz, 2 H), 7.51 (d, J ) 8.8 Hz, 2 H); IR ν
(KBr) cm-1 3360; MS m/z 220 (M+).
4-Meth oxyp h en ol (2j): colorless plates from Et2O-hexane;
mp 49-51 °C (lit.7 mp 55-57 °C); 1H NMR (CDCl3/TMS) δ 3.76
(s, 3H), 4.79 (br, 1H), 6.78-6.82 (m, 4H); IR ν (KBr) cm-1 3380;
MS m/z 124 (M+). Anal. Calcd for C7H9O2: C, 67.73; H, 6.50.
Found: C, 67.62; H, 6.48.
4-(Ben zyloxy)p h en ol (2k ): colorless plates from Et2O-
hexane; mp 119-120 °C (lit.8 mp 122 °C); 1H NMR (CDCl3/TMS)
δ 4.44 (s, 1 H), 5.01 (s, 2 H), 6.76 (d, J ) 9.1 Hz, 2H), 6.86 (d, J
) 9.1 Hz, 2 H), 7.34-7.41 (m, 5 H); IR ν (KBr) cm-1 3400; MS
m/z 200 (M+).
Exp er im en ta l Section
All melting points and boiling points are uncorrected. The IR
spectra were measured on a J ASCO IR-810 spectrophotometer.
1H NMR spectra were recorded on a Varian Gemini 2000 (300
MHz). Chemical shifts are expressed in δ (ppm) values with
tetramethylsilane (TMS) as the internal reference, and coupling
constants are expressed in hertz (Hz). The mass spectra (MS)
and high-resolution mass spectra (HRMS) were recorded on
J MS-DX303 and J MS-AX500 instruments, respectively.
4-Hyd r oxyp h en yl 4-m eth yl-1-ben zen esu lfon a te (2l): col-
1
orless solid; bp 205-215 °C/3 mmHg; H NMR (CDCl3/TMS) δ
2.45 (s, 3 H), 6.70 (d, J ) 8.8 Hz, 2 H), 6.83 (d, J ) 8.8 Hz, 2 H),
7.31 (d, J ) 8.5 Hz, 2 H), 7.69 (d, J ) 8.5 Hz, 2 H); IR ν (KBr)
P r ep a r a tion of Electr ogen er a ted Nick el. A platinum
sheet (1 × 2 cm2) as the cathode and a nickel sheet (1 × 2 cm2)
as the anode were placed in a 15 mL H-shaped undivided cell
that contained 0.3 M Et4NBF4-DMF (8 mL). Electrolysis was
(7) Pouchert, C. J .; Behnke J . The Aldrich Library of 13C and 1H
FT-NMR Spectra 2; Aldrich Chemical Commpany Inc.: New York,
1993; p 253, 254, 861, 943, 1250-1253, and 1520.
(8) Leznoff, C. C.; Dixit, D. M. Can. J . Chem. 1977, 55, 3351.