Synthesis, structure, and reactivity of a symmetrically substituted 9-Phosphatriptycene oxide and Its derivatives

Article abstract of DOI:10.1002/hc.20038

Novel 9-phosphatriptycenes were synthesized by utilizing ortho-lithiation of a triarylphosphine oxide as a key step. The structural analysis of the 9-phosphatriptycene oxide revealed its highly distorted structure around the phosphorus atom, which is consistent with the up-field shift in the ³¹P NMR spectrum. The 9-phosphatriptycene and its chalco-genides were synthesized by ordinary methods, and the spectral comparisons of these chalcogenides indicated the large s-character of the lone-pair orbital or the phosphorus-chalcogen σ bonds of those species. The 9-phosphatriptycene oxide was reacted with lithium naphthalenide to give the ring-opened products.

Full text of DOI:10.1002/hc.20038

Heteroatom Chemistry
Volume 15, Number 6, 2004
Synthesis, Structure, and Reactivity
of a Symmetrically Substituted
9-Phosphatriptycene Oxide and Its Derivatives
Tomohiro Agou, Junji Kobayashi, and Takayuki Kawashima
Department of Chemistry, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo,
Bunkyo-ku, Tokyo 113-0033, Japan
Received 13 May 2004
[1]. For example, its Caryl P Caryl angle is narrowed
ABSTRACT: Novel 9-phosphatriptycenes were syn-
compared to that of triphenylphosphine, which is
thesized by utilizing ortho-lithiation of a triarylphos-
revealed by the X-ray crystallographic analysis of 2-
phine oxide as a key step. The structural analysis of
(t-butyl)-9-phosphatriptycene [2,3]. Such a distorted
the 9-phosphatriptycene oxide revealed its highly dis-
structure around the phosphorus atom is suggested
torted structure around the phosphorus atom, which
in the solution as well as in the solid by the up-field
is consistent with the up-field shift in the 31P NMR
shifted signal in the 31P NMR spectrum.
spectrum. The 9-phosphatriptycene and its chalco-
The key step of the synthetic route to 9-
genides were synthesized by ordinary methods, and
phosphatriptycene reported by Bickelhaupt is the
the spectral comparisons of these chalcogenides indi-
intramolecular nucleophilic attack of the carban-
cated the large s-character of the lone-pair orbital or
ion to the benzyne generated by ortho-lithiation of
the phosphorus–chalcogen σ bonds of those species.
aryl chloride followed by elimination of chloride
The 9-phosphatriptycene oxide was reacted with
anion (Scheme 1). However, it is difficult to apply
lithium naphthalenide to give the ring-opened prod-
this method to the synthesis of 9-phosphatriptycenes
ꢀ
C
ucts.
2004 Wiley Periodicals, Inc. Heteroatom Chem
with various substituents on the aromatic rings be-
cause of difficulties in the preparation of starting ma-
terials. On the other hand, several heterotriptycenes
were synthesized utilizing ortho-metalation as a key
step [4].
15:437–446, 2004; Published online in Wiley InterScience
(www.interscience.wiley.com). DOI 10.1002/hc.20038
INTRODUCTION
Recently we reported the synthesis of a 9-
phosphatriptycene oxide utilizing ortho-lithiation of
a triarylphosphine oxide, and its structure was re-
vealed by the X-ray crystallographic analysis [5].
The large s-characters of the lone pair or the
phosphorus–chalcogen σ bond were also elucidated
by the NMR spectroscopy. Here we describe the syn-
thesis of 9-phosphatriptycenes as well as the struc-
tures of the multisubstituted 9-phosphatriptycene
oxides and the spectroscopic properties of the 9-
phosphatriptycene chalcogenides. Some reactions of
the 9-phosphatriptycene oxide are also described. A
part of this work has been communicated [5].
Heterotriptycenes have attracted great interest of
organic and inorganic chemists because of their
unique structures and spectroscopic properties. 9-
Phosphatriptycene, which was first synthesized by
Bickelhaupt in 1974, has interesting characteristics
Correspondence to: Takayuki Kawashima; e-mail: chem.s.u-
tokyo.ac.jp.
Contract grant sponsor: The Ministry of Education, Culture,
Sports, Science and Technology of Japan.
2004 Wiley Periodicals, Inc.
c
ꢀ
437

438 Agou, Kobayashi, and Kawashima
from o-dichlorobenzene and white phosphorus [6].
This synthesis, however, has several problems in
an application to the synthesis of multisubstituted
diphosphatriptycenes, because of the low regioselec-
tivity, as well as high reaction temperature and low
yield. As shown in Scheme 3, multisubstituted 9,10-
diphosphatriptycene oxide 5 was synthesized from
2 in 2 steps. The lithio-derivative of 2 was treated
with (PhO)3P to give phosphonite 4, the generation
of which was confirmed by the characteristic dou-
blet signals at δP 162.9 and 29.4, corresponding to
diaryl arylphosphonite and triarylphosphine oxide
fragments, respectively. Because the isolation of 4
was difficult due to its low stability against oxygen
and water, the mixture containing 4 was treated with
an excess amount of LDA to give 5 in 6% yield from
2. The reason of the low yield is probably side reac-
tions caused by the nucleophilic attack of LDA to the
phosphonite.
SCHEME 1
RESULTS AND DISCUSSION
Syntheses of 9-Phosphatriptycene Oxide and
9,10-Diphosphatriptycene Oxide
The synthesis of 9-phosphatriptycene oxide 1 is
shown in Scheme 2. Although the ortho-lithiation
of tris(3-methoxyphenyl)phosphine oxide (2) was ac-
complished with t-BuLi or lithium diisopropylamide
(LDA), the reactivity of the lithio-derivatives against
carbon electrophiles were dramatically changed by
the difference of base. When LDA was used as a base,
the reactivity of the carbanion decreased and the re-
action with carbonates did not proceed at all. The
coordination of (i-Pr)2NH to the carbanion probably
hampered the reaction. On the other hand, the an-
ion generated with t-BuLi reacted with (PhO)2CO or
ClCO2Me to give phenoxycarbonyl derivative 3. Mul-
tisubstituted 9-phosphatriptycene oxide (1) was ob-
tained by treatment of 3 with 2 equiv of LDA in 51%
yield. The overall yield of 1 is 33% from 2, which can
be easily obtained quantitatively from commercially
available 3-bromoanisole. So this synthetic method-
ology of the 9-phosphatriptycene derivative has an
advantage in both yield and number of steps com-
pared to the reported methods.
The 31P NMR spectrum of 1 showed the signal
at δP 2.1, which was up-field shifted by 28 ppm com-
pared to that of 2 (δP 30.3). This phenomenon is at-
tributable to the distortion around phosphorus atom
of 1, which was confirmed by the X-ray crystallo-
graphic analysis of 1. The signal of the hydroxy pro-
1
ton of 1 was observed at δH 6.18 in H NMR, in-
dicating the existence of intramolecular hydrogen
bond between the hydroxy group and the methoxy
group at the peri-position, compared to that of tris(2-
methoxyphenyl)methanol (δH 5.44). This intramolec-
ular hydrogen bond also affected the reactivity of the
hydroxy group; that is, the H–D exchange of the hy-
droxy proton did not occur with D2O, and a stronger
acid, DCl/D2O, was necessary for the exchange reac-
tion. As shown in Scheme 4, the hydroxy group could
not be methylated with MeI, because of the steric
hindrance by the three methoxy groups at the peri-
positions as well as the stabilization of the anionic
species by intramolecular chelating of the counter
This synthetic route to a phosphatriptycene
framework could be applied to the synthesis of a mul-
tisubstituted 9,10-diphosphatriptycene oxide. 9,10-
Diphosphatriptycene was synthesized by Weinberg
SCHEME 2
SCHEME 3

Synthesis, Structure, and Reactivity of a Symmetrically Substituted 9-Phosphatriptycene Oxide and Its Derivatives 439
SCHEME 4
cation. The methyl derivative 6 was obtained in 94%
yield by the use of a more powerful methylating
reagent, Me2SO4.
The 31P NMR spectrum of 5 showed the dou-
blet signals at δP −134.7 and 7.6, corresponding to
the triarylphosphine and the triarylphosphine ox-
ide fragments, respectively. The signal due to the
phosphine site of 5 was up-field shifted compared
to those of 9,10-diphosphatriptycene (δP −43). This
phenomenon is attributed to the steric compression
effect caused by the three methoxy groups at peri-
positions to the phosphorus atom. Because these
methoxy groups protect the phosphorus atom steri-
cally, 5 is unreactive against oxygen in both the solid
and the solution states. Neither the reactions of 5
with elemental sulfur and selenium at 75◦C nor that
with H2O2 at room temperature in CDCl3 proceeded
at all.
FIGURE 1 ORTEP drawing of 6 (50% probability). Hydro-
gen atoms and solvent molecules are omitted for clarity. Se-
◦
˚
lected bond lengths (A) and angles ( ): P(1) O(1) 1.4855(11),
P(1) C(1) 1.7798(13), P(1) C(2) 1.7714(13), P(1) C(3)
1.8009(14), C(1) P(1) C(2) 100.32(6), C(2) P(1) C(3)
98.10(6), C(1) P(1) C(3) 99.72(6).
Syntheses of a 9-Phosphatriptycene and its
Chalcogenides
In order to evaluate orbital hybridization and elec-
tronic state of phosphorus atoms in 9-phosphatri-
ptycene derivatives, the 9-phosphatriptycene and its
chalcogenides (Ch = S, Se) were synthesized from 1
(Scheme 5).
X-ray Crystallographic Analysis of
9-Phosphatriptycene Oxide
The single crystal of 6 was obtained by recrystal-
lization from CH2Cl2/MeOH, and the X-ray crystallo-
graphic analysis was performed. The ORTEP draw-
ing is shown in Fig. 1. The Caryl P Caryl angles of
6 [98.10(6), 99.72(6), and 100.32(6)] were also sub-
stantially narrowed as well as those of 1. The struc-
tural difference between 1 and 6 was observed in
the Caryl C10 Caryl angles. The differences between
the three Caryl C10 Caryl angles of 6 [104.76(9),
104.50(9), and 111.41(9)] are bigger than those of
1 [106.2(4), 105.6(2), and 109.0(4)], which suggest
the deviation from the C3v symmetry of the phospha-
triptycene framework of 6 due to the steric repul-
sion between the methyl group at C10 and the three
methoxy groups at the peri-positions.
The sulfurization of 1 proceeded by treatment of
1 with an excess amount of Lawesson’s reagent al-
1
most quantitatively estimated by H and 31P NMR
spectra; however, the isolated yield was low due to
poor solubility of 9-phosphatriptycene sulfide 7. 9-
Phosphatriptycene 8 was obtained by desulfuriza-
tion of 7 with (n-Bu)3P. 8 was also obtained by the
direct reduction of 1 with PhSiH3. The 31P NMR spec-
trum of 8 showed the signal at δP −68.7, which is
largely up-field shifted compared to that of tris(3-
methoxyphenyl)phosphine (δP −2.6) and nearly the
same as that of 9-phosphatriptycene (δP −64.8), in-
dicating the increase of magnetic shielding against
the phosphorus nuclei caused by distortion around
them. The PhSiH3 reduction could be applied to
6 and tetramethoxy-9-phosphatriptycene 9 was ob-
tained quantitatively. On the other hand, when
HSiCl3 was used for the reduction of 1, demethylated
derivative 10 was obtained [4e]. Further demethy-
lated products were not observed in this reaction,
even when the large excess amount of HSiCl3 was
The decrease in the bond angles around bridge-
head phosphorus atom is also observed in 9-phos-
phatriptycene (95.0◦) and its analogs, 9,10-azaphos-
phatriptycene (93.5◦) and 9,10-diphosphatriptycene
(97.0◦), revealed by X-ray crystallographic analyses
[7,8].

440 Agou, Kobayashi, and Kawashima
The Caryl P Caryl angles of the 9-phosphatri-
ptycene chalcogenides are thought to be narrower
than those of tris(3-methoxyphenyl)phosphine cha-
lcogenides, as shown in the X-ray crystallographic
analysis of 1. The deviation of the Caryl P Caryl an-
gles from that of tetrahedral structure (109.5◦) makes
it difficult for the phosphorus atom to take sp3 hy-
bridization in 9-phosphatriptycene chalcogenides.
Because of the decrease in the extent of the hy-
bridization in 9-phosphatriptycene chalcogenides,
the P Caryl bonds consist of more 3p orbitals of
the phosphorus atom and the P Ch σ bond con-
sists of more 3s orbitals than those of usual tri-
arylphosphine chalcogenides do. Absolute value of
1 JAB reflects participation of s orbital to σ bond be-
tween atom A and atom B. Taking into account these
1
theoretical considerations, the trends in JPC and
1 JPSe values are quite reasonable [9]. On the other
hand, the up-field shift in 31P NMR spectra are at-
tributed to the fact that the bonding electron pair has
more population near the phosphorus atom and the
magnetic shielding against the phosphorus nuclei
strengthens, because the P Ch σ bonds have large
phosphorus 3s character in 9-phosphatriptycene
selenide.
SCHEME 5
used. When 8 was allowed to react with elemental se-
lenium, the corresponding 9-phosphatriptycene se-
lenide 11 was obtained. Although the H and 31P
1
The 77Se NMR spectrum of 11 showed a signifi-
cantly up-field shifted signal at δSe −601.3 compared
to that of 13 (δSe −256). Although the reason for this
up-field shift is ambiguous, the calculated 77Se NMR
chemical shift of 11 (δSe −524) is close to the experi-
mental value [10–13].
NMR spectra showed that 8 was converted to 11
quantitatively, the low solubility of 11 decreased
its isolated yield, unfortunately. The spectroscopic
property of 9-phosphatriptycene chalcogenides 1, 7,
and 11 is discussed in the next section.
So it is revealed that the narrow Caryl P Caryl an-
gles in the 9-phosphatriptycene chalcogenides affect
the hybridization of the phosphorus atoms signifi-
cantly and the lone pair or the P Ch σ bonds have
large 3s character of the phosphorus atoms.
Spectroscopic Comparisons of
9-Phosphatriptycene Chalcogenides
The selected NMR spectral data of 1, 7, and 11 are
summarized in Table 1. The spectral data of tris(3-
methoxyphenyl)phosphine chalcogenides 2, 12, and
13 are also listed for comparisons. For 1, 7, and 11,
the 31P NMR spectra showed up-field signals with a
decrease in the 1 JPC values for 1, 7, and 11, compared
with those of the reference compounds 2, 12, and
13, respectively (Fig. 2). On the other hand, the 1 JPSe
value of 11 is larger than that of 13.
Reaction of 9-Phosphatriptycene Oxide with
Lithium Naphthalenide
The cyclic voltammogram of 6 was shown in Fig. 3.
The oxidation peak at 1.71 V may correspond to the
TABLE 1 Selected NMR Data of 9-Phosphatriptycene
Chalcogenides and Tris(3-methoxyphenyl)phosphine Chalco-
genides
δP
1JPC (Hz)
1JPSe (Hz)
1
7
11
2
12
13
2.1
10.0
3.9
30.3
44.6
38.1
93.0
75.9
67.8
103.1
84.3
76.0
—
—
827
—
—
732
FIGURE 2 The 9-Phosphatriptycene Chalcogenides and
Tris(3-methoxyphenyl)phosphine Chalcogenides.

Synthesis, Structure, and Reactivity of a Symmetrically Substituted 9-Phosphatriptycene Oxide and Its Derivatives 441
SCHEME 6
crystallographic analyses. The Cbridgehead Caryl bond
cleavage occurred by the reduction of the 9-phos-
phatriptycene oxide.
FIGURE 3 Cyclic voltammogram of 6.
EXPERIMENTAL
oxidation of aromatic ꢀ systems of 6. On the other
hand, the oxidation peak at 0.97 V should be at-
tributed a new species generated by reduction of 6,
because this peak appeared not in the first anodic
sweep but in the second sweep. So the chemical re-
duction with lithium naphthalenide (LiNaph) was
examined in order to obtain information about the
reduction process of 6.
As shown in Scheme 6, the reaction of 6 with 2
equiv of LiNaph gave 9,10-dihydroacridophosphine
oxides 14 and 15 that were obtained by the C10 Caryl
bond cleavage of 6.
General Information
All melting points are uncorrected. Solvents were pu-
rified before use by reported methods. All reactions
were carried out under dry argon atmosphere un-
less otherwise noted. H and 13C NMR spectra were
1
recorded on Bruker DRX500 and JEOL AL-400 spec-
trometers. 31P NMR spectra were recorded on JEOL
The plausible reaction mechanism was shown
in Scheme 7. The anion radical generated by one-
electron reduction of 6 undergoes the C10 Caryl bond
cleavage, and the 9,10-dihydroacridophosphine ox-
ide anion radical 16 is generated. The anionic frag-
ment in 16 is stabilized by the coordination of the
phosphoryl group and methoxy group to the lithium
atom, and the radical fragment is stabilized by the
mesomeric effect of the two aryl groups. 16 ab-
stracts hydrogen from the solvent successively to give
the corresponding anion 17. When 17 is quenched
by proton sources, 14 is obtained. Alternatively, the
further reduction of 17 causes the C10 OMe bond
cleavage, which is the usual benzyl ether cleavage,
and radical 18 is generated. 15 is obtained by hydro-
gen abstraction of 18 from the solvent followed by
protonation.
In summary, we have reported the synthesis
of the symmetrically multisubstituted 9-phosphatri-
ptycene oxide. The advantages of this method are
the decreased number of steps, the moderate yield,
and the ease of the introduction of many sub-
stituents into the aromatic rings. The NMR data
of the 9-phosphatriptycene chalcogenides indicated
the large s-character of the P Ch σ bond due to
the narrow C P C angle, indicated by the X-ray
SCHEME 7

442 Agou, Kobayashi, and Kawashima
(1.0 mL, 0.19 mmol) at −75◦C, which was freshly
Excalibur 270 and JEOL AL-400 spectrometers. 77Se
NMR spectra were recorded on a Bruker DRX500
spectrometer. All NMR spectra were recorded in
CDCl3 at 300 K, unless, otherwise mentioned. Chem-
ical shifts are reported in δ value, downfield posi-
i
prepared from Pr2NH (0.26 mL, 1.9 mmol) and n-
BuLi (1.63 M, hexane solution) (1.2 mL, 1.9 mmol)
in THF (10 mL), and the reaction mixture was stirred
for 5 h at −75◦C. The reaction mixture was grad-
ually warmed to room temperature, and the mix-
ture was treated with aqueous NH4Cl and extracted
with CHCl3. The extracts were dried over anhydrous
MgSO4. After removal of the solvent, the residue was
subjected to column chromatography on silica gel
using AcOEt as elutant to give 1 as colorless solids
(16.7 mg, 52%).
tive, and relative to tetramethylsilane for 1H and 13
C
NMR, 85% H3PO4 for 31P NMR, or dimethylselenide
for 77Se NMR. High-performance liquid chromatog-
raphy (HPLC) was performed by LC-918 and LC-908
C60 with JAIGEL 1H + 2H columns (Japan Analyti-
cal Industry) with chloroform as solvent. EI-MS and
FAB-MS were recorded on Shimadzu QP-5000 and
JEOL JMS-700P, respectively.
1: Colorless solids; mp 330–332◦C (dec.); 1H
NMR (500 MHz, CDCl3) δ 3.86 (s, 9H), 6.18 (s, 1H),
6.95 (d, J = 7.8 Hz, 3H), 7.20 (td, J = 7.8, 3.4 Hz,
Tris(3-methoxyphenyl)phosphine, oxide 2, and
sulfide 12 were prepared according to the reported
methods [14,15].
1
3H), 7.62 (dd, J = 12.3, 7.8 Hz, 3H); 13C{ H} NMR
(125 MHz, CDCl3) δ 57.66 (s), 83.69 (d, J = 23.1 Hz),
117.11 (d, J = 1.9 Hz), 120.62 (d, J = 5.0 Hz), 127.69
(d, J = 14.1 Hz), 134.76 (d, J = 93.0 Hz), 137.75 (d,
Synthesis of Bis(3-methoxyphenyl)-
2-phenoxycarbonylphenylphosphine Oxide (3)
1
J = 7.3 Hz), 157.16 (d, J = 13.5 Hz); 31P{ H} NMR
t-BuLi (2.65 M, pentane solution) (6.0 mL, 16 mmol)
was added dropwise to a stirred solution of 2 (3.8 g,
10 mmol) in THF (300 mL) at −75◦C and the reac-
tion mixture was stirred for 2 h at −75◦C. After the
addition of a solution of (PhO)2CO (3.4 g, 16 mmol)
in THF (30 mL), the reaction mixture was warmed to
0◦C and stirred overnight. The mixture was treated
with aqueous NH4Cl and extracted with CHCl3. The
extracts were dried over anhydrous MgSO4. After re-
moval of the solvent, the residue was subjected to
column chromatography on silica gel using 3:1 mix-
ture of AcOEt/hexane as elutant to give a fraction
containing 3, which was further purified by recrys-
tallization from AcOEt (1.54 g, 31%). 3 was also ob-
tained in 60% yield by the use of ClCO2Me instead of
(PhO)2CO.
(109 MHz, CDCl3) δ 2.0; HRMS (FAB+, m-NBA):
m/z calcd for C22H20O5P 395.1048, found 395.1031
([M + H+]).
Synthesis of 9,10-Diphosphatriptycene Oxide (5)
To a solution of 1 (492.0 mg, 1.3 mmol) in THF
(100 mL) was added t-BuLi (2.65 M, pentane
solution) (0.73 mL, 1.9 mmol) at −75◦C, and the
reaction mixture was stirred at −75◦C for 2 h. After
the addition of (PhO)3P (0.50 mL, 1.9 mL) to this
mixture, the mixture was warmed to 0◦C and stirred
overnight at 0◦C. After the generation of 4 was
confirmed by 31P NMR, the mixture was cooled to
−75◦C and LDA (0.39 M, THF solution) (10 mL, 3.9
mmol), which was freshly prepared from (i-Pr)2NH
(0.54 mL, 3.9 mmol) and n-BuLi (1.63 M, hexane
solution) (2.4 mL, 3.9 mmol) in THF (10 mL), was
added. After the reaction mixture was warmed
to room temperature gradually, the mixture was
treated with aqueous NH4Cl and extracted with
CHCl3. The extracts were dried over anhydrous
MgSO4. After the removal of the solvent, the residue
was recrystallized from CHCl3/EtOH to give 5 as
colorless solids (28.6 mg, 6%).
3: Colorless solids; mp 141–143◦C; 1H NMR (500
MHz, CDCl3δ 3.71 (s, 6H), 3.92 (s, 3H), 6.89 (ddd,
J = 12.5, 7.5, 0.5 Hz, 1H), 7.03 (dt, J = 8.5, 1.3 Hz,
1
2H), 7.12–7.20 (m, 5H), 7.26–7.41 (m, 8H); 13C{ H}
NMR (125 MHz, CDCl3) δ 55.17 (s), 56.15 (s), 114.90
(s), 116.50 (d, J = 10.8 Hz), 118.17 (d, J = 2.1 Hz),
121.76 (s), 124.16 (d, J = 10.1 Hz), 124.47 (d, J =
10.0 Hz), 125.44 (s), 127.09 (d, J = 7.4 Hz), 128.93
(s), 129.38 (d, J = 14.6 Hz), 130.25 (d, J = 13.9
Hz), 131.21 (d, J = 100.1 Hz), 133.34 (d, J = 104.5
Hz), 150.81 (s), 157.21 (d, J = 12.6 Hz), 159.30 (d,
5: Colorless solids; mp 368–370◦C (dec.); 1H
NMR (500 MHz, CDCl3) δ 3.90 (s, 9H), 6.87 (dd,
J = 7.8, 5.2 Hz, 3H), 7.35 (td, J = 7.8, 4.0 Hz, 3H),
1
J = 15.1 Hz), 164.63 (d, J = 4.8 Hz); 31P{ H} NMR
(106 MHz, CDCl3) δ 30.4; HRMS (FAB+, m-NBA):
m/z calcd for C28H26O6P 489.1467, found 489.1440
([M + H+]).
1
7.75 (dd, J = 10.7, 7.8 Hz, 3H); 13C{ H} NMR (125
MHz, CDCl3) δ 55.93 (s), 112.41 (s), 122.39 (d, J = 7.6
Hz), 129.56 (s), 130.10 (d, J = 13.6 Hz), 139.97 (d,
1
J = 104.0 Hz), 161.74 (dd, J = 21.0, 13.1 Hz); 31P{ H}
Synthesis of 9-Phosphatriptycene Oxide (1)
NMR (162 MHz, CDCl3) δ −134.7 (d, J = 17.0 Hz),
7.6 (d, J = 17.0 Hz); HRMS (FAB+, m-NBA): m/z
calcd for C21H18O4P2 396.0680, found 396.0688 (M+).
To a solution of 3 (39.9 mg, 82 ꢁmol) in THF
(1 mL) was added LDA (0.19 M, THF solution)

Synthesis, Structure, and Reactivity of a Symmetrically Substituted 9-Phosphatriptycene Oxide and Its Derivatives 443
added (n-Bu)3P (50 ꢁl, 0.20 mmol) at room temper-
ature. After a few freeze-pump-thaw cycles, the tube
was sealed in vacuo and the suspension was heated
at 130◦C for 5 d. After confirmation of disappearance
of 7 by 31P NMR spectroscopy, the sealed tube was
opened and the solvent was removed under reduced
pressure. The crude products were separated by
HPLC to afford 8 as colorless solids (11.4 mg, 71%).
H–D Exchange Reaction of 1
In a 5-mm diameter NMR tube, D2O or DCl/D2O was
added to a solution of 1 (5.0 mg, 13 ꢁmol) in CDCl3
(0.75 mL) at room temperature. The reaction was
monitored by 1H NMR spectroscopy.
Synthesis of 9-Phosphatriptycene Oxide (6)
A suspension of 1 (133 mg, 0.34 mmol) and NaH
(60 wt % in mineral oil, 0.10 g, 2.5 mmol) in THF
(20 mL) was stirred for 10 min at room tempera-
ture. To this mixture was added Me2SO4 (0.10 mL,
1.1 mmol), and the mixture was refluxed overnight.
The mixture was treated with aqueous NH4Cl and
extracted with CHCl3. The extracts were dried over
anhydrous MgSO4. After removal of the solvent, the
residue was subjected to HPLC to give 6 as colorless
solids (130.4 mg, 94%).
Reduction of 1 with PhSiH3
A suspension of 1 (43.3 mg, 0.11 mmol) in PhSiH3
(8.0 mL) was refluxed overnight, and the quantitative
conversion of 1 to 8 was confirmed by 31P NMR spec-
troscopy. The excess PhSiH3 was removed under re-
duced pressure to give 8 as colorless solids (40.1 mg,
96%).
8: Colorless solids; mp 235–238◦C; 1H NMR (500
MHz, CDCl3) δ 3.89 (s), 6.33 (s, 1H), 6.86 (d, J = 7.7
Hz, 3H), 7.03 (td, J = 7.7, 2.3 Hz, 3H), 7.39 (dd, J =
6: Colorless solids; mp 318–322◦C (dec.); 1H
NMR (500 MHz, CDCl3) δ 3.86 (s, 3H), 3.88 (s, 9H),
6.96 (d, J = 7.7 Hz, 3H), 7.21 (td, J = 7.7, 3.0 Hz,
1
10.9, 7.7 Hz, 3H); 13C{ H} NMR (125 MHz, CDCl3) δ
57.88 (s), 88.65 (s), 116.26 (s), 125.73 (d, J = 38.8
Hz), 126.81 (d, J = 14.6 Hz), 128.49 (d, J = 12.0
1
3H), 7.65 (dd, J = 12.5, 7.7 Hz, 3H); 13C{ H} NMR
(125 MHz, CDCl3) δ 57.12 (s), 58.70 (s), 87.90 (d, J =
21.6 Hz), 119.09 (s), 121.24 (d, J = 4.5 Hz), 127.78
(d, J = 14.3 Hz), 135.55 (d, J = 93.8 Hz), 136.93 (d,
Hz), 132.09 (d, J = 9.9 Hz), 157.43 (s); 31P{ H} NMR
1
(109 MHz, CDCl3) δ −68.7; HRMS (FAB+, m-NBA):
m/z calcd for C22H20O4P 379.1099, found 379.1088
([M+H+]).
1
J = 6.8 Hz), 156.55 (d, J = 13.4 Hz); 31P{ H} NMR
(109 MHz, CDCl3) δ 2.1; HRMS (FAB+, m-NBA): m/z
calcd for C23H21O5P 408.1127, found 408.1129 (M+).
Reduction of 1 with HSiCl3
Synthesis of 9-Phosphatriptycene Sulfide (7)
In a 5-mm-diameter NMR tube, to the suspension
of 1 (19.2 mg, 49 ꢁmol) in toluene-d8 (1.0 mL)
were added HSiCl3 (0.20 mL, 2.0 mmol) and NEt3
(0.30 mL, 2.2 mmol). After a few freeze-pump-thaw
cycles, the tube was sealed in vacuo and the suspen-
sion was heated at 120◦C for 2 d. After confirmation
of disappearance of 1 by 31P NMR spectroscopy, the
sealed tube was opened. The mixture was treated
with degassed ice-water and extracted with CHCl3.
The extracts were dried over anhydrous MgSO4. The
solvents were removed under reduced pressure to
give 10 as colorless solids (17.6 mg, 99%).
A suspension of 1 (45.7 mg, 0.12 mmol) and Lawes-
son’s reagent (234.5 mg, 0.58 mmol) in toluene (10
mL) was refluxed overnight. After removal of the sol-
vent, the residue was subjected to HPLC to give a
fraction containing 7, which was further purified by
recrystallization from CHCl3/EtOH to give 7 as col-
orless solids (17.1 mg, 36%).
7: Colorless solids; mp 325–327◦C (dec.); 1H
NMR (500 MHz, CDCl3) δ 3.91 (s, 9H), 6.26 (s, 1H),
6.97 (d, J = 8.0 Hz, 3H), 7.21 (td, J = 8.0, 3.7 Hz,
1
3H), 7.69 (dd, J = 14.8, 8.0 Hz, 3H); 13C{ H} NMR
10: Colorless solids; mp 245–248◦C; 1H NMR
(500 MHz, CDCl3) δ 3.91 (s, 6H), 6.73 (d, J = 7.8 Hz,
1H), 6.86 (d, J = 7.7 Hz, 2H), 6.98 (td, J = 7.8, 1.8
Hz, 1H), 7.04 (td, J = 7.7, 1.7 Hz, 2H), 7.26 (ddd,
J = 10.6, 7.8, 1.8 Hz, 1H), 7.39 (ddd, J = 10.5, 7.7,
(125 MHz, CDCl3) δ 57.69 (s), 116.98 (s), 121.27 (d,
J = 8.8 Hz), 127.43 (d, J = 13.1 Hz), 134.68 (d, J =
75.9 Hz), 136.58 (d, J = 4.3 Hz), 157.00 (d, J = 12.0
1
Hz); 31P{ H} NMR (109 MHz, CDCl3) δ 10.0; HRMS
(FAB+, m-NBA): m/z calcd for C22H20O4PS 411.0820,
found 411.0808 (M + H+).
1
1.7 Hz, 2H), 8.06 (s, 1H), 11.00 (s, 1H); 13C{ H}
NMR (125 MHz, CDCl3) δ 57.44 (s), 90.00 (d, J =
1.9 Hz), 115.25 (s), 119.02 (s), 123.51 (d, J = 37.9
Hz), 126.05 (d, J = 38.3 Hz), 127.00 (d, J = 14.1
Hz), 127.49 (d, J = 14.4 Hz), 130.62 (d, J = 2.8 Hz),
136.50 (d, J = 3.3 Hz), 139.11 (d, J = 5.8 Hz), 142.20
The signal of the bridgehead carbon of 7 could
not be observed because of the low solubility.
Desulfurization of 7
1
In a 5-mm-diameter NMR tube, to a suspension of
7 (17.1 mg, 42 ꢁmol) in toluene-d8 (0.75 mL) was
(d, J = 8.8 Hz), 155.72 (s), 156.42 (s); 31P{ H} NMR
(109 MHz, CDCl3) δ −68.4; LRMS (EI): m/z 364 (M+).

444 Agou, Kobayashi, and Kawashima
13: Colorless solids; mp 141–143◦C. 1H NMR
(500 MHz, CDCl3) δ 3.78 (s, 9H), 7.00 (dq, J = 7.9, 1.1
Hz, 3H), 7.16 (ddd, J = 12.9, 7.9, 1.1 Hz, 3H), 7.29–
Synthesis of 9-Phosphatriptycene 9
A suspension of 6 (530.4 mg, 1.3 mmol) in PhSiH3
(2.0 mL) was refluxed overnight. After confirmation
of quantitative conversion of 6 to 9 by 31P NMR spec-
troscopy, the solvent was removed under reduced
pressure. The residue was separated by HPLC to give
9 as colorless solids (169 mg, 33%).
1
7.38 (m, 6H); 13C{ H} NMR (125 MHz, CDCl3) δ 55.23
(s), 117.38 (s), 117.79 (d, J = 13.0 Hz), 124.47 (d, J =
10.0 Hz), 129.38 (d, J = 14.5 Hz), 132.73 (d, J = 76.0
1
Hz), 159.29 (d, J = 15.8 Hz); 31P{ H} NMR (109 MHz,
1
1
CDCl3) δ 38.1 (s, satellite, JPSe = 733 Hz); 77Se{ H}
9: Colorless solids; mp 218–220◦C; 1H NMR (400
MHz, CDCl3) δ 3.87 (s, 9H), 3.89 (s, 3H), 6.86 (d,
J = 7.6 Hz, 3H), 7.03 (td, J = 7, 6, 2.0 Hz, 3H), 7.41
1
NMR (95 MHz, CDCl3) δ −256 (d, JPSe = 733 Hz);
HRMS (FAB+, m-NBA): m/z calcd for C21H22O3P80Se
433.0472, found 433.0459 ([M+H+]).
1
(dd, J = 11.1, 7.6 Hz, 3H); 13C{ H} NMR (125 MHz,
CDCl3) δ 56.94 (s), 58.99 (s), 92.33 (s), 118.38 (s),
126.41 (d, J = 39.3 Hz), 126.76 (d, J = 14.8 Hz),
127.40 (d, J = 15.8 Hz), 131.48 (d, J = 9.4 Hz),
Reduction of 6 with Lithium Naphthalenide
To a solution of 6 (67.5 mg, 0.17 mmol) in THF
(10 mL) at −75◦C was added LiNaph (1.0 M THF
solution) (0.33 mL, 0.33 mmol), which was prepared
according to the reported method [16], and the reac-
tion mixture was warmed to 0◦C. After the mixture
was stirred at 0◦C for 1 h, it was treated with aque-
ous NH4Cl and extracted with CHCl3. The extracts
were dried over anhydrous MgSO4. After removal of
the solvent, the residue was separated by HPLC and
column chromatography on silica gel using AcOEt
as elutant to give 14 (7.8 mg, 11%) and 15 (43.3 mg,
67%) as colorless solids.
1
156.85 (s); 31P{ H} NMR (162 MHz, CDCl3) δ −64.8;
HRMS (FAB+, m-NBA) m/z calcd for C23H21O4P
392.1177, found 392.1121 (M+).
Synthesis of 9-Phosphatriptycene Selenide (11)
In a 5-mm-diameter NMR tube, to a suspension of
8 (11.3 mg, 30 ꢁmol) in CDCl3 (0.75 mL) was added
elemental selenium (28.3 mg, 0.36 mmol). After a
few freeze-pump-thaw cycles, the tube was sealed in
vacuo and heated at 75◦C for 5 h. After confirmation
of disappearance of 8 by 31P NMR, the sealed tube
was opened. The residual elemental selenium was
filtered off, and the solvent was removed under re-
duced pressure. The residue was subjected to HPLC
to give 11 as colorless solids (4.9 mg, 33%).
14: Colorless solids; mp 194–196◦C; 1H NMR
(500 MHz, CDCl3) δ 3.18 (s, 3H), 3.71 (s, 3H), 3.93
(s, 6H), 6.51 (s, 1H), 6.89 (dd, J = 7.9, 2.1 Hz, 1H),
7.11 (d, J = 7.6 Hz, 2H), 7.22 (td, J = 7.9, 3.9 Hz,
1H), 7.30–7.35 (m, 2H), 7.48 (td, J = 7.6, 3.0 Hz,
11: Colorless solids; mp 336–338◦C (dec.); 1H
NMR (500 MHz, CDCl3) δ 3.92 (s, 9H), 6.30 (s, 1H),
6.98 (d, J = 7.7 Hz, 3H), 7.21 (tdd, J = 7.7, 4.0, 1.0
1
2H), 7.81 (dd, J = 11.3, 7.6 Hz, 2H); 13C{ H} NMR
(125 MHz, CDCl3) δ 55.25 (s), 55.84 (s), 56.52 (s),
63.36 (d, J = 10.8 Hz), 114.10 (d, J = 2.3 Hz), 115.85
(d, J = 12.4 Hz), 117.45 (d, J = 2.6 Hz), 123.51 (d,
J = 5.6 Hz), 123.61 (d, J = 10.6 Hz), 129.63 (d, J =
9.6 Hz), 129.25 (d, J = 15.0 Hz), 129.91 (d, J = 13.1
Hz), 132.59 (d, J = 99.1 Hz), 136.22 (d, J = 107.6
Hz), 157.20 (d, J = 13.8 Hz), 159.08 (d, J = 15.9 Hz);
Hz, 3H), 7.71 (ddd, J = 15.6, 7.7, 1.0 Hz, 3H); 13C{ H}
1
NMR (125 MHz, CDCl3) δ 57.76 (s), 117.14 (s), 122.50
(d, J = 10.4 Hz), 127.37 (d, J = 16.1 Hz), 133.55
(d, J = 67.8 Hz), 136.31 (d, J = 2.9 Hz), 156.91 (d,
1
J = 11.3 Hz); 31P{ H} NMR (202 MHz, CDCl3) δ 4.7
1
(s, satellite, 1 JPSe = 828 Hz); 77Se{ H} NMR (95 MHz,
1
31P{ H} NMR (109 MHz, CDCl3) δ 11.6; HRMS (FAB+,
CDCl3) δ −601.3 (d, 1 JPSe = 828 Hz); HRMS (FAB+, m-
NBA): m/z calcd for C22H20O4P80Se 459.0264, found
459.0277 ([M+H+]).
m-NBA): m/z calcd for C23H23O5P 410.1283, found
410.1265 (M+).
15: Colorless solids; mp 250–254◦C; 1H NMR
(500 MHz, CDCl3) δ 3.58 (dd, J = 22.0, 3.3 Hz, 1H),
3.75 (s, 3H), 3.92 (s, 6H), 4.63 (dd, J = 22.0, 2.4 Hz,
1H), 6.89–6.96 (m, 2H), 7.03 (d, J = 7.9 Hz, 2H), 7.13
(dd, J = 13.7, 1.2 Hz, 1H), 7.20 (td, J = 8.0, 3.5 Hz,
1H), 7.39 (td, J = 7.9, 2.8 Hz, 2H), 7.60 (dd, J = 11.6,
The signal of the bridgehead carbon could not be
observed because of the low solubility of 9.
Synthesis of Tris(3-methoxyphenyl)phosphine
Selenide (13)
1
7.9 Hz, 2H);13C{ H} NMR (125 MHz, CDCl3) δ 22.72
A suspension of tris(3-methoxyphenyl)phosphine
(213.0 mg, 0.61 mmol) and elemental selenium
(180.0 mg, 2.3 mmol) in CHCl3 (10 mL) was refluxed
for 7 h. The residual elemental selenium was filtered
off, and the solvent was removed under reduced pres-
sure to give 11 as colorless solids (225.0 mg, 85%).
(d, J = 10.8 Hz), 55.33 (s), 55.59 (s), 112.71 (s),
115.75 (d, J = 11.3 Hz), 117.15 (s), 122.42 (d, J = 6.4
Hz), 122.94 (d, J = 10.4 Hz), 127.89 (d, J = 13.4 Hz),
129.25 (d, J = 10.5 Hz), 129.611 (d, J = 13.8 Hz),
129.612 (d, J = 102.0 Hz), 136.20 (d, J = 106.3
Hz), 156.29 (d, J = 13.9 Hz), 159.37 (d, J = 15.1 Hz);

Synthesis, Structure, and Reactivity of a Symmetrically Substituted 9-Phosphatriptycene Oxide and Its Derivatives 445
1
31P{ H} NMR (109 MHz, CDCl3) δ 11.2; HRMS (FAB+,
Union Road, Cambridge CB2 1EZ, UK (fax: +44 1223
336 033; e-mail: deposit@ccdc.cam.ac.uk).
m-NBA): m/z calcd for C22H21O4P 380.1177, found
380.1171 (M+).
Computational Methods
Cyclic Voltammetry of 6
Structural optimizations were performed using the
B3LYP functional theory with the 6-31G(d) basis set
[10,11]. The NMR shielding tensors were computed
with the GIAO methods at the B3LYP/6-31G(d) level
of theory [12]. All calculations were performed using
GAUSSIAN03 program package [13].
The cyclic voltammetry of 6 was performed under
dry argon atmosphere at room temperature using
an ALS 617A voltammetric analyzer. Conditions: sol-
vent, degassed CH2Cl2 with 0.1 M (n-Bu)4NClO4as the
supporting electrolyte; working electrode, glassy car-
bon; counter electrode, Pt wire; reference electrode,
Ag/0.01 M AgNO3/0.1 M (n-Bu)4NClO4/CH3CN; scan
rate, 30 mVs−1.
ACKNOWLEDGMENTS
We thank Tosoh Finechem Corporation and Shin-
etsu Chemical Corporation for the generous gifts of
alkyllithiums and silanes, respectively.
Crystallographic Studies of 6
The intensities of reflection were collected at 120
K on a RIGAKU MSC Mercury CCD diffractometer
with a graphite monochromated Mo-Kꢂ radiation
(ꢃ = 0.71069 A) using CrystalClear (Rigaku Corp.).
REFERENCES
˚
[1] Jongsma, C.; De Kleijn, J. P.; Bickelhaupt, F. Tetrahe-
dron 1974, 30, 3465.
[2] Daly, J. J. J Chem Soc 1964, 3799.
[3] Van der Putten, N.; Stam, C. H. Acta Crystallogr 1980,
B36, 1250.
The data were corrected for Lorentz polarization ef-
fects. The crystallographic and experimental data
are listed in Table 2. The structures were solved
by the direct method (SIR 97) and expanded using
Fourier techniques. The structures were refined by
full-matrix least squares on F2 (SHELXS-97) [17].
The nonhydrogen atoms were refined anisotropi-
cally, and hydrogen atoms were refined isotropically.
Coordinates and other crystallographic infor-
mation were deposited with Cambridge Crystallo-
graphic Database Centre as supplementary publi-
cation No. CCDC-237879. Copies of data can be
obtained free of charge on application to CCDC, 12
[4] (a) Ishii, A.; Kodachi, M.; Nakayama, J.; Hoshino,
M. J Chem Soc, Chem Commun 1991, 751; (b)
Takahashi, M.; Hatano, K.; Kawada, Y.; Koga, G.;
Tokitoh, N.; Okazaki, R. J Chem Soc, Chem Com-
mun 1993, 1850; (c) Ishi, A.; Tsuchiya, T.; Nakayama,
J.; Hoshino, M. Tetrahedron Lett 1993, 34, 2347; (d)
Ishii, A.; Takaki, I.; Nakayama, J.; Hoshino, M. Tetra-
hedron Lett 1993, 34, 8255; (e) Ishii, A.; Yoshioka, R.;
Nakayama, J.; Hoshino, M. Tetrahedron Lett 1993,
34, 8259; (f) Dam, M. A.; Akkerman, O. S.; de Kanter,
F. J. J.; Bickelhaupt, F.; Veldman, N.; Spek, A. L. Chem
Eur J 1996, 2, 1139; (g) Ishii, A.; Nakayama, J. Rev
Heteroatom Chem 1994, 11, 1.
[5] Kobayashi, J.; Agou, T.; Kawashima, T. Chem Lett
2003, 32, 1144.
[6] Weinberg, K. G. J Org Chem 1975, 40, 3586.
[7] Hellwinkel, D.; Schenk, W.; Blaicher, W. Chem Ber
1978, 111, 1798.
[8] Schomburg, D.; Sheldrick, W. S. Acta Crystallogr
1975, B31, 2427.
[9] Tolman, C. A. Chem Rev 1977, 77, 313.
[10] (a) Becke, A. D. J Chem Phys 1993, 98, 5648. (b) Lee,
C.; Yang, W.; Parr, R. G. Phys Rev 1988, B37, 785.
[11] (a) For H, C, and O: Hariharan, P. C.; Pople, J. A. Theor
Chim Acta 1973, 28, 213; (b) For P and S: Francl,
M. M.; Pietro, W. J.; Hehre, W. J.; Binkley, J. S.;
DeFrees, D. J.; Pople, J. A.; Gordon, M. S. J Chem
Phys 1982, 77, 3654; (c) For Se: Rassolov, V. A.;
Ratner, M. A.; Pople, J. A.; Redfern, P. C.; Curtiss, L. A.
J Comp Chem 2001, 22, 976.
[12] (a) London, F. J Phys Radium, Paris 1937, 8, 397; (b)
McWeeny, R. Phys Rev 1962, 126, 1028; (c) Ditchfield,
R. Mol Phys 1974, 27, 789; (d) Dodds, J. L.; McWeeny,
R.; Sadlej, A. J. Mol Phys 1980, 41, 1419; (e) Wolinski,
K.; Hilton, J. F.; Pulay, P. J Am Chem Soc 1990, 112,
8251.
TABLE 2 Crystallographic Data of 6
Formula
C24H25O5P
120 K
Temperature
Crystal system
Space group
Triclinic
¯
P 1
˚
a (A)
8.320(3)
10.071(3)
13.903(6)
70.146(12)
88.178(17)
68.718(13)
˚
b (A)
˚
c (A)
α (degree)
β (degree)
γ (degree)
3
˚
V (A )
1015.4(7)
2
Z
Calculated density
Reflection collected
Unique
R1 (I > 2.00 σ(I ))
wR2 (all data)
1.441 g cm−3
7630
4331
0.0349
0.0931
1.065
Goodness-of-Fit

446 Agou, Kobayashi, and Kawashima
[13] Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria,
G. E.; Robb, M. A.; Cheeseman, J. R.; Montgomery,
J. A., Jr.; Vreven, T.; Kudin, K. N.; Burant, J. C.;
Millam, J. M.; Iyengar, S. S.; Tomasi, J.; Barone,
V.; Mennucci, B.; Cossi, M.; Scalmani, G.; Rega, N.;
Petersson, G. A.; Nakatsuji, H.; Hada, M.; Ehara,
M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.;
Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Klene,
M.; Li, X.; Knox, J. E.; Hratchian, H. P.; Cross, J. B.;
Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann,
R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli,
C.; Ochterski, J. W.; Ayala, P. Y.; Morokuma, K.; Voth,
G. A.; Salvador, P.; Dannenberg, J. J.; Zakrzewski, V.
G.; Dapprich, S.; Daniels, A. D.; Strain, M. C.; Farkas,
O.; Malick, D. K.; Rabuck, A. D.; Raghavachari, K.;
Foresman, J. B.; Ortiz, J. V.; Cui, Q.; Baboul, A. G.;
Clifford, S.; Cioslowski, J.; Stefanov, B. B.; Liu, G.;
Liashenko, A.; Piskorz, P.; Komaromi, I.; Martin, R.
L.; Fox, D. J.; Keith, T.; Al-Laham, M. A.; Peng, C.
Y.; Nanayakkara, A.; Challacombe, M.; Gill, P. M. W.;
Johnson, B.; Chen, W.; Wong, M. W.; Gonzalez, C.;
Pople, J. A. GAUSSIAN03, Revision B.10; Gaussian,
Inc., Pittsburgh PA, 2003.
[14] Sinou, D.; Maillard, D.; Pozzi, G. Eur J Org Chem
2002, 269.
[15] Grindley, T. B.; Johnson, K. F.; Kaack, H.; Katritzky,
A. R.; Schiemenz, G. P.; Topsom, R. D. Aust J Chem
1975, 28, 327.
[16] Jutzi, P.; Hielscher, B. Organometallics 1986, 5, 1201.
[17] Sheldrick, G. M. SHELXL 97: Program for Crys-
tal Structure Refinement; University of Go¨ttingen:
Gottingen, Germany, 1997.