Synthesis of a Quintet Tetraphenoxyl Tetraradical
J . Org. Chem., Vol. 62, No. 22, 1997 7583
74% yield as pale yellow crystals: GC/MS, 50-250 °C, 10 °C/
min, m/z 466 (M+) at 24.1 min; 1H NMR, CDCl3, δ ) 1.42 ppm,
s, 36H; 3.76, s, 6H; 7.43, s, 4H; FTIR, KBr, ν ) 1655 cm-1
(CdO); mp ) 165-167 °C (lit.52 mp 165 °C).
ppm, s, 8H; 13C NMR, d8-THF, δ ) 28.5, 31.1, 35.3, 50.6, 126.1,
135.3, 137.1, 138.5, 153.3, 155.0; FTIR, NaCl, ν ) 3641, 3618
(sharp, OH) cm-1; UV/vis, λmax ) 241 nm; mp > 360 °C. Anal.
Calcd for C66H96O4: C, 83.14; H, 10.15; O, 6.71. Found: C,
83.25; H, 10.21; O, 6.24.
Bis(3,5-d i-ter t-b u t yl-4-m et h oxyp h en yl)m et h ylh yd r a -
zon e (11).35,36 Anhydrous H2NNH2 (2.8 mL, 0.087 mol), 10
(4.08 g, 0.00874 mol), and a few drops of glacial AcOH were
added to absolute EtOH (100 mL). After being refluxed for
12 h, the mixture was cooled to room temperature and the
solvent removed. Recrystallization from MeOH gave diaryl-
hydrazone 11 (3.99 g, 0.00831 mol) in 95% yield as pale yellow
crystals: GC/MS, 50-250 °C, 10 °C/min, m/z 480 (M+) at 28.0
min; 1H NMR, CDCl3, δ ) 1.38 ppm, s, 18H; 1.44, s, 18H; 3.71,
s, 3H; 3.77, s, 3H; 5.2 broad s, 2H; 7.20, s, 2H; 7.43, s, 2H;
FTIR, NaCl, ν ) 1590 cm-1 (CdN).
P r ep a r a tion of 1.5 M CH3SLi/HMP A.40 Under an argon
atmosphere, 125 mL of HMPA was distilled from BaO (75 °C,
0.4 Torr) onto LiH (4.58 g, 0.576 mol). This mixture was cooled
with an ice bath, and CH3SH (35.3 mL, 0.188 mol, collected
at -78 °C) was added via cannula. After being stirred at room
temperature for 12 h, the mixture was vacuum filtered through
a Schlenk line fine glass sinter. The concentration (1.50 (
0.01 M) was determined by titration with 0.1501 M potassium
hydrogen pthalate.
Bisga lvin ol 7.4-16,41 Tetraphenol 3 (0.287 g, 0.000301 mol)
was stirred in benzene (50 mL) and purged thoroughly with
argon. A solution of Bu4NOH/MeOH (1.0 M, 3.6 mL, 0.0036
mol) was added, and the mixture was allowed to stir until 3
had dissolved completely, about 5 min. A solution of I2 in
benzene (0.0301 M, 20.3 mL, 0.000612 mol) was added via
syringe, resulting immediately in a dark blue-purple color. The
reaction was stirred for an additional 10 min and then
quenched by carefully adding half-saturated NH4Cl (20 mL).
The organic layer was dried and reduced to a brown solid. The
residue was purified by column chromatography using 1-10%
Et2O/petroleum ether as eluant to give bisgalvinol 7 (0.237 g,
0.249 mmol) in 83% yield as a bright orange solid. A portion
of this was recrystallized from MeOH for X-ray analysis: 58
Bisep isu lfid e 13.22,35-38 A mixture of 11 (2.59 g, 0.00539
mol), freshly activated HgO (2.85 g, 0.0132 mol), NaSO4 (1.22
g, 0.00862 mol), 5 drops of saturated KOH/absolute EtOH
solution, and Et2O (100 mL) was stirred under a drying tube
for 45 min. The intensely purple mixture was vacuum filtered
through a fine glass sinter. The purple residue after solvent
removal was presumably bis(3,5-di-tert-butyl-4-methoxyphe-
nyl)diazomethane (see Scheme 1: TLC, violet spot at Rf 0.7,
no stain, 33% Et2O/petroleum ether; FTIR, NaCl, ν ) 2031
(NdN), 1590, (CdN) cm-1). This residue (2.58 g, 0.00539 mol)
and 1222,52 (0.464 g, 0.00269 mol) were added to Et2O (50 mL).
Slight warming and gas evolution was observed. Upon stirring
overnight, the color went from deep purple to light gold. The
solid precipitated by cooling to 0 °C was collected by vacuum
filtration and washed with a minimum of cold Et2O. Drying
gave bisepisulfide 13 (2.17 g, 0.00202 mol) in 75% yield as a
white powder: 90 MHz 1H NMR, CDCl3, δ ) 0.46, ppm, s, 3H;
0.66, s, 3H; 0.95, s, 3H; 1.21, s, 3H; 1.40, s, 72H; 3.61, s, 12H;
7.74, s, 8H. Anal. Calcd for C70H104O4S2: C, 78.30; H, 9.76;
S, 5.97. Found: C, 78.03; H, 10.01; S, 5.87.
HRMS, FAB, found MW
) 952.731600, calcd MW )
952.730862, for MH+ ) C66H95O4; 1H NMR (see also Figure
8), acetone-d6 with slight excess of LiOD, δ ) 1.15 ppm, s, 36H;
1.30, s, 36H; 1.52, s, 6H; 2.16, s, 6H; 6.93, s, 4H; 7.11, s, 4H;
FTIR, NaCl, ν ) 3636 (sharp, OH) 1602 (CdO) cm-1; UV/vis,
neutral, λmax ) 395 nm, ꢀ ) 36 950; dianion, λmax ) 602 nm, ꢀ
) 110 830; mp ) 175-176 °C. Anal. Calcd for C66H94O4: C,
83.32; H, 9.96; O, 6.73. Found: C, 83.02; H, 10.07; O, 6.79.
1,1-Dim eth yl-2,2-bis(3,5-di-ter t-bu tyl-4-m eth oxyph en yl)-
eth ylen e.56,57 Benzophenone 10 (2.17 g, 0.00465 mol) was
dissolved in THF (50 mL) and cooled to 0 °C. To this was
added isopropylmagnesium chloride (2.0 M, 2.3 mL, 0.0047
mol). After the solution was stirred for 2 h at room temper-
ature, the reaction was cooled with an ice water bath and
quenched by carefully adding H2O (10 mL), and the alcohol
intermediate was dehydrated by adding concentrated HCl (10
mL). This mixture was extracted with Et2O, dried, filtered,
and reduced to a solid. Recrystallization of the residue from
MeOH gave the bisanisole precursor to 15 (2.06 g, 0.00418 mol)
in 92% yield as white crystals: GC/MS, 50-250 °C, 10 °C/
min, m/z 492 (M+) at 22.4 min; 1H NMR, CDCl3, δ ) 1.33 ppm,
s, 36H; 1.81, s, 6H; 3.63, s, 6H;, 6.94, s, 4H; 13C NMR, CDCl3,
δ ) 23, 33, 37, 65, 129, 130, 138, 143, 158 ppm.
Activa tion of HgO.39 Mercury(II) oxide (5.0 g, 0.023 mol)
was dissolved, with stirring, in concentrated HClO4. After the
mixture was cooled in an ice bath, 50% NaOH was added
dropwise until the mixture was basic. The orange precipitate
was collected by vacuum filtration and dried to give activated
HgO (4.9 g, 0.023 mol).
1,3-Bis(bis(3,5-d i-ter t-bu tyl-4-m eth oxyp h en yl)m eth yl-
en e)-2,2,4,4,-tetr a m eth ylcyclobu ta n e (14).22 Bisepisulfide
13 (1.35 g, 0.00126 mol) and triphenylphosphine (0.66 g, 0.0025
mol) were added to 100 mL of benzene and refluxed for 48 h.
The residue after solvent removal was boiled for 10 min in 50
mL of a 1:1 solution of CCl4 and 95% EtOH. After removing
this solvent, the residue was washed with 95% EtOH and dried
to give tetraanisole 14 (1.21 g, 0.00120 mol) in 95% yield as a
white powder: HRMS, found MW ) 1008.7924, calcd MW )
1008.7935, for M+ ) C70H104O4; 1H NMR, CDCl3, δ ) 0.97 ppm,
s, 12H; 1.44, s, 72H; 3.74, s, 12H; 6.95, s, 8H; 13C NMR, CDCl3,
δ ) 27.7, 32.2, 35.5, 49.6, 64.2, 127.1, 136.4, 136.9, 142.2, 154.3,
157.8 ppm; mp > 360 °C. Anal. Calcd for C70H104O4: C, 83.28;
H, 10.38; O, 6.34. Found: C, 83.39; H, 10.26; O, 6.29.
1,3-Bis(bis(3,5-d i-ter t-bu tyl-4-h yd r oxyp h en yl)m eth yl-
en e)-2,2,4,4,-tetr a m eth ylcyclobu ta n e (3).40 Under an ar-
gon atmosphere, 9.6 mL (0.014 mol) of 1.5 M CH3SLi/HMPA
was added to tetraanisole 14 (1.21 g, 0.00120 mol). (Note: O2
and H2O must be rigorously excluded.) The mixture was
heated to 85 °C. Because the final product cannot be easily
purified from methoxy intermediates, the reaction was run
until no methoxy compounds were visible by TLC (removal of
each methyl results in spots at successively lower Rfs),
although this resulted in some product decomposition. After
10 d, the reaction, which had turned green, was quenched with
H2O (10 mL), stirred for 5 min, and then stirred for 1 h with
concentrated HCl (20 mL) to destroy the HMPA. The mixture
was extracted with CH2Cl2, dried, filtered, and reduced to a
solid. The residue was washed on a fine glass sinter with 500
mL each of boiling H2O and boiling CH3CN. Drying gave
tetraphenol 3 (0.686 g, 0.000719 mol) in 60% yield as a white
powder: TLC, blue grey spot at Rf 0.25, molybdate stain, 5%
EtOAc/petroleum ether; HRMS, FAB, found MW ) 952.731600,
calcd MW ) 952.730862 for M+ ) C66H96O4; 1H NMR, d8-THF,
δ ) 0.97 ppm, s, 12H; 1.37 ppm, s, 72H; 5.90 ppm, s, 4H; 7.11
1,1-Dim eth yl-2,2-bis(3,5-di-ter t-bu tyl-4-h ydr oxyph en yl)-
eth ylen e (15).54 Ethanethiol (2.3 mL, 0.044 mol) was added
to a stirred suspension of NaH (1.15 g, 0.0479 mol) in DMF
(75 mL). After the bubbling ceased, 1,1-dimethyl-2,2-bis(3,5-
di-tert-butyl-4-methoxyphenyl)ethylene (see above, 1.48 g,
0.00318 mol) was added and the mixture was heated to 100
°C for 2 days. The reaction, which had turned dark brown,
was quenched by carefully adding H2O (10 mL), stirred for 5
min, and stirred for 1 h with 6 M HCl (100 mL). The mixture
was poured into H2O, extracted with Et2O, dried, and reduced
to a solid. Recrystallization of the residue from MeOH gave
bisphenol 15 (0.753 g, 0.00162 mol) in 51% yield as air-
sensitive white microcrystals (these slowly turned yellow even
in a glovebox): GC/MS, 50-250 °C, 10 °C/min, m/z 464 (M+)
1
at 23.8 min; H NMR, CDCl3, δ ) 1.41 ppm, s, 36H; 1.81, s,
6H;, 5.06, s, 2H; 6.96, s, 4H; 13C NMR, CDCl3, δ ) 22.9, 30.5,
24.4, 108, 126.3, 129.5, 134.7, 151.5 ppm. Anal. Calcd for
(56) Hoye, T. R.; Martin, S. J .; Peck, D. R. J . Org. Chem. 1982, 47,
331-337.
(57) Carey, F. A.; Sundberg, R. J . Advanced Organic Chemistry;
Plenum: New York, 1990; Part A, p 454.
(58) The author has deposited atomic coordinates for structure 7
with the Cambridge Crystallographic Data Centre. The coordinates
can be obtained, on request, from the Director, Cambridge Crystal-
lographic Data Centre, 12 Union Road, Cambridge, CB2 1EZ, U.K.