Heteroatom effects toward isomerization of intermediates in Wittig reactions of non-stabilized phosphonium ylides bearing a phosphaheteratriptycene skeleton with benzaldehyde

Article abstract of DOI:10.1002/hc.21473

Isomerization of intermediates, cis- and trans-1,2-oxaphosphetanes, in Wittig reactions of non-stabilized phosphonium ylides bearing a phosphaheteratriptycene skeleton containing group 14 (PhSi, PhGe, PhSn, n-BuSn) and 15 (P, As, Sb, and Bi) elements with benzaldehyde (PhCHO) was investigated by variable-temperature (VT)³¹P{¹H} NMR spectroscopy. The isomerization from the cis-1,2-oxaphosphetane to the trans-form occurred at lower temperatures as the row number of the same group elements increases. Wittig reactions under the same conditions gave the (Z)-olefin as a major product in the cases of period 3 elements (PhSi and P) and the (E)-olefin as a major product in the cases of elements from period 4 and below (PhGe, PhSn, n-BuSn, As, Sb, and Bi). The selectivity of olefin formation is considered to depend on the isomerization temperature of the intermediates, because each olefin must be obtained from the corresponding 1,2-oxaphosphetane. The VT-³¹P{¹H} NMR spectra showed that the cis-1,2-oxaphosphetanes were the kinetic products in the first step of Wittig reactions and the trans-forms were the thermodynamically stable products formed by isomerization from the cis-forms via ring-opening and ring-closing reactions of phosphonium ylides with PhCHO. Density functional theory (DFT) calculations indicated that cis-1,2-oxaphosphetanes were less stable than the trans-forms by ~2?kcal/mol, supporting thermodynamically favorable isomerization from cis-forms to trans-forms, as observed by VT-³¹P{¹H} NMR spectroscopy. Heteroatoms at the bridgehead position of the phosphaheteratriptycene skeleton significantly affected the isomerization temperature as well as the phosphorus-31 signals in the ³¹P{¹H} NMR spectra, which were observed at lower field as row number of the same group element increases.

Full text of DOI:10.1002/hc.21473

Received: 29 September 2018
DOI: 10.1002/hc.21473
Revised: 21 November 2018
Accepted: 21 November 2018
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S P E C I A L I S S U E : A T R I B U T E T O P R O F E S S O R
N A O M I C H I F U R U K AWA O N T H E O C C A S I O N O F
H I S 8 2 N D B I R T H D AY - B Y I N V I T AT I O N O N LY
Heteroatom effects toward isomerization of intermediates in
Wittig reactions of non-stabilized phosphonium ylides bearing a
phosphaheteratriptycene skeleton with benzaldehyde
Yosuke Uchiyama
|
Suguru Kuniya
|
Ryo Watanabe
|
Takemaru Ohtsuki
Department of Chemistry, School of
Science, Kitasato University, Sagamihara,
Kanagawa, Japan
Abstract
Isomerization of intermediates, cis- and trans-1,2-oxaphosphetanes, in Wittig reactions
of non-stabilized phosphonium ylides bearing a phosphaheteratriptycene skeleton con-
taining group 14 (PhSi, PhGe, PhSn, n-BuSn) and 15 (P, As, Sb, and Bi) elements with
Correspondence
Yosuke Uchiyama, Department of
Chemistry, School of Science, Kitasato
University, Sagamihara, Kanagawa, Japan.
Email: yosuke@kitasato-u.ac.jp
31
1
benzaldehyde (PhCHO) was investigated by variable-temperature (VT) P{ H} NMR
spectroscopy. The isomerization from the cis-1,2-oxaphosphetane to the trans-form
occurred at lower temperatures as the row number of the same group elements in-
creases. Wittig reactions under the same conditions gave the (Z)-olefin as a major prod-
uct in the cases of period 3 elements (PhSi and P) and the (E)-olefin as a major product
in the cases of elements from period 4 and below (PhGe, PhSn, n-BuSn, As, Sb, and
Bi). The selectivity of olefin formation is considered to depend on the isomerization
temperature of the intermediates, because each olefin must be obtained from the cor-
Funding information
Ministry of Education, Culture, Sports,
Science, and Technology of Japan, Grant/
Award Number: 16750041 and 18750037;
Ogasawara Foundation for Oversea
Visiting Researchers; Mikiya Foundation
for Oversea Visiting Researchers; Kitasato
University Research Grant for Young
Researchers; Murata Science Foundation
31
1
responding 1,2-oxaphosphetane. The VT- P{ H} NMR spectra showed that the cis-
,2-oxaphosphetanes were the kinetic products in the first step of Wittig reactions and
1
the trans-forms were the thermodynamically stable products formed by isomerization
from the cis-forms via ring-opening and ring-closing reactions of phosphonium ylides
with PhCHO. Density functional theory (DFT) calculations indicated that cis-1,2-
oxaphosphetanes were less stable than the trans-forms by ~2 kcal/mol, supporting
thermodynamically favorable isomerization from cis-forms to trans-forms, as observed
31
1
by VT- P{ H} NMR spectroscopy. Heteroatoms at the bridgehead position of the
phosphaheteratriptycene skeleton significantly affected the isomerization temperature
31
1
as well as the phosphorus-31 signals in the P{ H} NMR spectra, which were ob-
served at lower field as row number of the same group element increases.
Dedicated to Professor Naomichi Furukawa on the occasion of his 82nd birthday.
Contract grant sponsor: Murata Science Foundation
Contract grant sponsor: Ministry of Education, Culture, Sports, Science, and Technology of Japan
Contract grant number: 16750041
Contract grant number: 18750037
Contract grant sponsor: Ogasawara Foundation for Oversea Visiting Researchers
Contract grant sponsor: Mikiya Foundation for Oversea Visiting Researchers
Contract grant sponsor: Kitasato University Research Grant for Young Researchers
Heteroatom Chemistry. 2018;e21473.
https://doi.org/10.1002/hc.21473
wileyonlinelibrary.com/journal/hc
© 2018 Wiley Periodicals, Inc.
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2
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UCHIYAMA et Al.
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1
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INTRODUCTION
1,2-oxaphosphetanes, which have been predicted by theoret-
[
15]
ical calculations, were evidenced by isolation of these in-
[16]
Numerous mechanistic studies on the Wittig reaction have in-
dicated that the 1,2-oxaphosphetanes, which are regarded as a
termediates and reported by Akiba et al for the first time.
In contrast to the role of a bidentate ligand to stabilize
highly coordinate 1,2-oxaphosphetanes, a tridentate ligand
based on a phosphastibatriptycene skeleton did not show any
stabilization of the intermediates, but resulted in the pro-
motion of isomerization from the cis-1,2-oxaphosphetane
to the trans-form in the Wittig reaction of a non-stabilized
[
2 + 2] cycloadduct constructed by a phosphonium ylide with
a carbonyl compound, are detectable and isolatable intermedi-
[1–4] 31
ates.
P NMR spectroscopy has been used as a powerful
[
5]
investigative tool to detect intermediates since Vedejs and
[3,6]
Maryanoff
observed signals due to 1,2-oxaphosphetanes in
[17–19]
Wittig reactions of a non-stabilized triphenylphosphonium ylide
phosphonium ylide with PhCHO.
The Wittig reac-
[5–7]
with a carbonyl compound.
However, 1,2-oxaphosphetanes
tion yielded the (E)-olefin as a major product, with the cis-
1,2-oxaphosphetane being observed only in the initial step
of this reaction, when monitored by variable-temperature
with π-conjugated substituents, such as phenyl and carbonyl
groups, at the 3-position in the triphenylphosphine system
31
31
1
have never been detected by P NMR spectroscopy; these are
regarded as intermediates in the reactions of a semi-stabilized
phosphonium ylide or a stabilized phosphonium ylide with a
carbonyl compound. These substituents at the neighboring po-
sition of phosphorus in the phosphonium ylides promote the
decomposition of 1,2-oxaphosphetane due to its slightly polar
(VT) P{ H} NMR spectroscopy. This indicated that cis-
1,2-oxaphosphetane had been isomerized to the trans-form,
because (Z)- and (E)-olefins were produced from cis- and
trans-1,2-oxaphosphetanes, respectively. This isomerization
is known as the stereochemical drift in Wittig reactions of
non-stabilized phosphonium ylides with a carbonyl com-
pound, and shows the difference between the isomer ratio
of the initial intermediates and that of the resulting ole-
[
8]
transition state in the second step of the Wittig reaction.
Since 1,2-oxaphosphetanes have a trigonal bipyramidal
TBP) structure, bidentate ligands that enable the forma-
[
3,6,20,21]
(
fins.
The stereochemical drift has been reported to
tion of a five-membered ring stabilize such a TBP structure
thermodynamically by occupying the apical and equatorial
depend on the substituent groups, such as phenyl and n-butyl
[3,6,20]
groups, on the phosphorus of the 1,2-oxaphosphetane.
[
9]
positions. For example, Vedejs et al developed a novel
dibenzophosphole system to stabilize the 1,2-oxaphosphetane
with a vinyl group at the 3-position and observed its sig-
The phosphastibatriptycene system significantly affected the
stereochemical drift unlike the tri-n-butylphosphine system,
resulting in the selective formation of (E)-olefin in the Wittig
reaction of non-stabilized phosphonium ylide with PhCHO.
Wehavebeeninterestedinheteroatomeffectsatthebridge-
head position of the phosphaheteratriptycenes; these are the
group 14 (PhSi, PhGe, PhSn, n-BuSn) and group 15 (P, As,
3
1
[10,11]
nal by P NMR spectroscopy.
The Martin bidentate
ligand has been used to stabilize highly coordinate hetero-
[
12,13]
atom compounds.
Kawashima et al reported the isola-
tion and crystal structure of the 1,2-oxaphosphetane with a
methoxycarbonyl group at the 3-position bearing the Martin
[22,23]
Bi) element analogues of the phosphastibatriptycene.
In
[
14]
bidentate ligand. They claimed that the compound recog-
nized as a formal [2 + 2] cycloadduct of a stabilized phos-
phorus ylide and a carbonyl compound could be obtained as
a stable compound and that the methoxycarbonyl group at
the 3-position accelerated the olefin formation reaction. In
the same bidentate ligand system, O-apical and O-equatorial
this paper, we report heteroatom effects on the isomerization
from cis-1,2-oxaphosphetanes to the trans-forms in Wittig
reactions of non-stabilized phosphonium ylides bearing the
phosphaheteratriptycene skeleton with PhCHO. We also
3
1
1
report the P{ H} NMR spectra of the related compounds
based on the experimental and theoretical results.
SCHEME 1 Synthesis of ethylphosphonium iodides 9-16 and non-stabilized phosphonium ylides 17-24 bearing the phosphaheteratriptycene
skeleton

UCHIYAMA et Al.
3 of 17
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2
2
RESULTS AND DISCUSSION
|
.1
Ethylation of phosphaheteratriptycenes
|
and generation of non-stabilized phosphonium
ylides
Phosphaheteratriptycenes 1-8 containing group 14 and 15 el-
ements, which were synthesized by the same method as phos-
[
24]
[25,26]
phasilatriptycene and phosphastibatriptycene 7,
were
reacted with ethyl iodide in CHCl to give ethylphosphonium
3
iodides 9-16 (Scheme 1). These ethylphosphonium iodides
9
-16 were identified by (a) the phosphorus-31 signals that
were detected at lower field than those of phosphaheteratrip-
tycenes 1-8, (b) proton signals of the CH CH group observed
3
2
in the alkyl region, and (c) their H–H and P–H couplings.
Non-stabilized phosphonium ylides 17-24 bearing the phos-
phaheteratriptycene skeleton were generated in a yellow THF
solution by the deprotonation of ethylphosphonium iodides
9
-16 with (TMS) NNa at 0°C (Scheme 1). Non-stabilized
2
phosphonium ylides 17-24 generated in THF were examined
1
31
1
in situ by H and P{ H} NMR spectroscopy. Unfortunately,
the characteristic ylidic proton signals could not be observed
due to the THF solvent signals, which were much larger than
those of the desired phosphonium ylides 17-24. However, the
3
1
1
phosphorus-31 signals in the P{ H} NMR spectra of 17-
2
4 in THF were at notably higher field than those of 9-16
in CDCl , whose chemical shifts were compared in differ-
3
ent solvents because of their solubility in THF (Scheme 1,
Table 1, and Figure 1). Wittig reactions were conducted by
the addition of PhCHO to the yellow solutions below −90°C.
The color change from yellow to colorless indicated that the
Wittig reactions started at −90°C and the formation of inter-
mediates also proceeded at the same temperature (Scheme 2,
Table 1, and Figure 1).
2
.2
P-Si and P-Sn coupling
|
constants of phosphasilatriptycenes, Sn-
phenylphosphastannatriptycenes, and Sn-n-
butylphosphastannatriptycenes
The P-Si coupling constant of ethyl phosphonium salt 9
(
56.6 Hz), which depended on the oxidation state of phos-
phorus, was observed to be ~8 times larger number than
2
9
that of phosphasilatriptycene 1 (7.15 Hz) in Si NMR
spectra. The P-Sn coupling constants of 11 and 12 (302.6
and 237.9 Hz, respectively) were ~5 times larger than
1
19
those of 3 and 4 (65.0 and 48.8 Hz, respectively) in Sn
NMR spectra. Similarly, the coupling constants of 11 and
1
2 were 302.4 and 237.9 Hz, respectively, and those of 3
31
and 4 were 64.0 and 50.0 Hz, respectively, in the P NMR
spectra, indicating the presence of oxidized phosphorus
atoms in these compounds. Non-stabilized phosphonium
3
1
ylide 20 and trans-1,2-oxaphosphetane 28b in the P NMR

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UCHIYAMA et Al.
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1
-8
3
3-40
25-32
9-16
17-24
17
Group 14
M = PhSi
33
34
35
9
1
2
25b
25a
M = PhGe
M = PhSn
10 18
26b
26a
11
19
3
27b
27a
M = n-BuSn
Group 15
36
12 20
4
28b
28a
[ppm]
50
0
–50
M = P
37 13
21
5
29b
29a
M = As
38 14
22
6
30b
30a
M = Sb
M = Bi
39
15 23
8
7
31b
31a
40 16
24
32b
32a
[ppm]
50
0
–50
FIGURE 1 Systematic comparison of the 31P NMR chemical shifts of phosphorus compounds
SCHEME 2 Wittig reactions of non-stabilized phosphonium ylides 17-24 with PhCHO
spectra had P-Sn coupling constants of 237.2 and 236.7 Hz,
respectively, similar to that of ethylphosphonium salt 12.
However, the P–Sn coupling constant of phosphine oxide 36
was 267.0 Hz, which was somewhat larger than that of 12,
3 and 11 showed larger P-Sn coupling constants than the
n-butyl derivatives 4 and 12, demonstrating the substituent
effect on the tin atom. The results indicated that substitu-
ents on the heteroatom at the bridgehead position affected
the phosphorus atom and its oxidation state (in other words,
the difference in the s-character of the bond), and directly
induced the large change from the pyramidal structure of
2
0, and 28b. The P-Sn coupling constants were almost the
same when the oxidation state and substituents on the phos-
phorus atom were the same. However, phenyl derivatives

UCHIYAMA et Al.
5 of 17
|
(
A)
2
.3
X-ray crystallographic analysis of Sn-
|
phenylphosphastannatriptycenes
In order to investigate the structure around the phospho-
rus atom, X-ray analysis was carried out on the single
crystals of phenylphosphastannatriptycenes 3 and 11 ob-
tained from CHCl -acetone and CH Cl -benzene, re-
C9
C7
3
2
2
spectively (Figure 2 and Table 3). The results showed
that the pyramidal geometry around phosphorus atom in
Figure 2A changed to a tetrahedral geometry upon eth-
ylation of Sn-phenylphosphastannatriptycene 3, as shown
in Figure 2B. That is, the P–C bonds of 11 are somewhat
shorter than those of 3, whereas the C–P–C angles of 11 are
somewhat larger than those of 11. On the other hand, Sn-
phenylphosphastannatriptycene 3 has a tetrahedral structure
around tin atom with the Sn–C bonds and C–Sn–C angles
described in Figure 2A. These are similar to those of the
ethylphosphonium derivative 11 having Sn–C bonds and
C–Sn–C angles, as shown in Figure 2B. These bond lengths
and angles around the phosphorus and tin atoms affected the
spatial distances between phosphorus and tin, P···Sn (3.293
and 3.180 Å), as well as in the reported structures of phos-
phastibatriptycenes 7 and 15 having P···Sb distances, 3.482
and 3.349 Å.[
C4
C8
Sn1
C6
P1
C5
C3
(
B)
C9
C7
17]
C4
C8
Sn1
2.4
Wittig reactions of non-stabilized
|
C6
I1
C5
phosphonium ylides with PhCHO
P1
C2
Wittig reactions of non-stabilized phosphonium ylides 17-
C3
C1
24 with PhCHO at −90°C gave (Z)- and (E)-olefins through
1
,2-oxaphosphetanes 25-32 as intermediates, which were
observed at temperatures between −90°C and 25°C by VT-
3
1
1
P{ H} NMR spectroscopy (Scheme 2). Wittig reactions at
90°C provided the (Z)-olefin as a major product in the cases
−
of period 3 elements (PhSi and P) and (E)-olefin as a major
product in the cases of elements from period 4 and below
(PhGe, PhSn, n-BuSn, As, Sb, and Bi) in moderate yields to-
gether with phosphine oxides 33-40 (Scheme 2 and Table 2).
The selectivity in Wittig reactions at 0°C agreed with that at
FIGURE 2 Crystal structure of phenylphosphatriptycenes 3
and 11, selected bond lengths (Å) of 3 are P1–C3; 1.855(2), P1–C4;
1
.860(2), P1–C5; 1.855(2), Sn1–C6; 2.134(2), Sn1–C7; 2.131(2),
Sn1–C8; 2.134(2), Sn1-C9; 2.116(2), P1···Sn1; 3.293, selected bond
angles (°) of 3 are C3–P1–C4; 101.55(7), C3–P1–C5; 100.60(7), C4–
P1–C5; 102.04(7), C6–Sn1–C7; 96.95(6), C6–Sn1–C8; 97.14(6), C6–
Sn1–C9; 117.13(6), C7–Sn1–C8; 97.54(6), C7–Sn1–C9; 125.53(6),
C8–Sn1–C9; 119.16(6), selected bond lengths (Å) of 11 are P1–C1;
−
90°C except for that of the ylide bearing the diphosphatrip-
tycene skeleton, although an increase and decrease in the
selectivity were observed. The presence of a particular heter-
oatom resulted in the selective formation of (E)-olefin for the
period 4 and below elements of both groups 14 and 15 similar
to that reported for the antimony system.[
1
.795(3), P1–C3; 1.811(3), P1–C4; 1.809(3), P1–C5; 1.807(3), Sn1–
C6; 2.154(3), Sn1–C7; 2.150(3), Sn1–C8; 2.161(3), Sn1–C9; 2.114(3),
P1···Sn1; 3.180, selected bond angles (°) of 11 are C1–P1–C3;
1
17]
12.59(13), C1–P1–C4; 111.67(13), C1–P1–C5; 110.63(13), C3–P1–
C4; 107.62(12), C3–P1–C5; 105.54(12), C4–P1–C5; 108.52(12), C6–
Sn1–C7; 123.86(10), C6–Sn1–C8; 94.24(10), C6–Sn1–C9; 96.29(10),
C7–Sn1–C8; 96.58(10), C7–Sn1–C9; 123.70(10), C8–Sn1–C9;
2
.5
Observation of intermediates by VT-
|
31
1
P{ H} NMR spectroscopy
1
15.93(10)
These (E)-selective Wittig reactions were induced by the ste-
reochemical drift caused by the isomerization from cis-1,2-
oxaphosphetanes 25a-32a to the trans-forms 25b-32b, as
shown in Scheme 3. The isomerization temperatures of the
phosphines 3 and 4 to tetrahedral or trigonal bipyramidal
structures of the phosphonium salts 11 and 12, phospho-
nium ylide 20, and trans-1,2-oxaphosphetane 28b.

6
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UCHIYAMA et Al.
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TABLE 2 (Z)/(E)-Ratios of produced olefins and yields (%) in Wittig reactions, isomerization temperature (°C), and electronegativity
a,b
a,c
(
Z)/(E) ratio (Yield
(Z)/(E) ratio (Yield
Isomerization
a
a
temperatured
Electronegativitye,f
Entry
M
[%] )
[%] )
1
2
3
4
5
6
7
8
PhSi
PhGe
PhSn
n-BuSn
P
62 : 38 (38)
17 : 83 (72)
21 : 79 (34)
26 : 74 (45)
51 : 49 (15)
35 : 65 (32)
13 : 87 (87)
26 : 74 (42)
87 : 13 (47)
22 : 78 (55)
12 : 88 (55)
11 : 89 (47)
48 : 52 (57)
36 : 64 (50)
20 : 80 (70)
25 : 75 (58)
−20
−50
−50
−60
0
−20
−40
−60
1.74
2.02
1.82
1.82
2.06
2.20
1.82
1.67
As
Sb[
17]
Bi
a
b
c
1
Integration ratio at 25°C in H NMR spectra estimation yield toward the inner standard, Ph C=CH .
2
2
Wittig reactions at −90°C.
Wittig reactions at 0°C.
d
31
1
Temperature as trans-form increased in VT- P{ H} NMR spectra.
e
f
[27]
Electronegativity (Allred-Rochow).
[27]
Carbon; 2.50.
3
1
1
SCHEME 3 Observation of isomerization from cis-1,2-oxaphosphetanes 25a-32a to trans-form 25b-32b by VT- P{ H} NMR spectroscopy
3
1
1
1
,2-oxaphosphetanes 25-32 bearing the phosphaheteratrip-
VT- P{ H} NMR spectroscopic studies of all the reac-
tions showed that cis-1,2-oxaphosphetanes 25a-32a were
almost the exclusive kinetic products at −90°C. The highly
selective cis-1,2-oxaphosphetane formation was observed in
these phosphaheteratriptycene systems without exception,
which was quite different from the results of the triphen-
tycene skeleton containing group 14 and 15 elements were
31
1
studied by VT- P{ H} NMR spectroscopy (Figure 3). The
temperature decreased as the row number of the same group
elements increases, that is, −20°C for 25, −50°C for 26,
−
50°C for 27, and −60°C for 28 in the cases of group 14 ele-
[4,5,17]
ments and 0°C for 29, −20°C for 30, −40°C for 31, and −60°C
for 32 in the cases of group 15 elements (Table 2). In the Sn
system, substituent effect of the phenyl and n-butyl groups was
ylphosphine and tri-n-butylphosphine systems.
The
cis-1,2-oxaphosphetanes produced were isomerized to the
thermodynamically stable trans-forms, which were fol-
lowed by the decomposition of the 1,2-oxaphosphetane ring
to give the olefin and phosphine oxides 33-40. Therefore,
the phosphaheteratriptycene skeletons generated cis-1,2-
oxaphosphetanes 25a-32a as initial major products in the
Wittig reactions.
31
1
observed by the VT- P{ H} NMR measurement, wherein the
n-butyl group on Sn promoted isomerization more effectively
than the phenyl group. The observed isomerization tempera-
ture affected the selectivity of the olefin in Wittig reactions of
non-stabilized phosphonium ylides 17-24 with PhCHO. The
dependence of the accelerated isomerization of intermediates
on the heteroatoms at another bridgehead position of the phos-
phaheteratriptycene skeleton was in a good agreement with the
result of (E)-selective olefin formation in Wittig reactions. The
heteroatom effect was comparable with the tendency of elec-
The intermediates bearing
cene skeleton in the Wittig reactions, cis- and trans-1,2-
oxaphosphetanes 25-32, were observed as a sharp signal in the
a
phosphaheteratripty-
3
1
1
VT- P{ H}NMRspectraexceptforcis-1,2-oxaphosphetanes
27a and 28a bearing Sn-phenylphosphastannatriptycene and
Sn-n-butylphosphastannatriptycene skeletons, respectively.
These oxaphosphetanes were observed as broad signals
(Figure 3). In the phosphastibatriptycene system, such broad
+
−
tronegativity, inducing M(δ )–C(δ ) polarization in the phos-
phaheteratriptycene skeleton, which led to the retro-[2 + 2]
cycloaddition reaction of cis-1,2-oxaphosphetane.

UCHIYAMA et Al.
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2
5 ℃
M = PhSi
25 ℃
0 ℃
M = PhGe
1
1
0 ℃
0
℃
0
℃
–
10 ℃
–10 ℃
20 ℃
–30 ℃
–
–
20 ℃
trans-form 25b
–80.0)
(
δ
P,–20
C
–30 ℃
–
40 ℃
–
–
–
–
–
40 ℃
50 ℃
60 ℃
70 ℃
80 ℃
–
50 ℃
trans-form 26b
–81.0)
(
δ
P,–40
C
–60 ℃
–70 ℃
–80 ℃
–90 ℃
cis-form 25a
cis-form 26a
(
δ
P,–80
C
–81.8)
(δP,–80
C
–82.8)
–90 ℃
–78
–80
–82
–84
–82
–84
–86
–80
2
5 ℃
0 ℃
M = PhSn
25 ℃
0 ℃
M = n-BuSn
1
0
℃
–
–
–
10 ℃
20 ℃
30 ℃
–
–
–
–
–
–
–
–
–
10 ℃
20 ℃
30 ℃
40 ℃
50 ℃
60 ℃
70 ℃
80 ℃
90 ℃
–40 ℃
–50 ℃
–60 ℃
–70 ℃
–80 ℃
trans-form 27b
–74.7)
cis-form 27a
(
δ
P,–50
C
(δP,–50
C
–76.2)
trans-form 28b
–73.7)
(
δ
P,–60
C
cis-form 28a
(
δ
P,–90
C
–75.6)
–90 ℃
–72
–74
–76
–78
–72
–74
–76
–78
25 ℃
25 ℃
25 ℃
25 ℃
10 ℃
M = P
25 ℃
0 ℃
M = As
1
0
℃
–10 ℃
0
℃
–20 ℃
trans-form 29b
P,0
trans-form 30b
P,–20
(
δ
C
–78.2)
–
–
–
–
–
–
–
–
–
10 ℃
20 ℃
30 ℃
40 ℃
50 ℃
60 ℃
70 ℃
80 ℃
90 ℃
(δ
C
–71.3)
–30 ℃
–
40 ℃
50 ℃
–
–60 ℃
–
70 ℃
80 ℃
–
cis-form 29a
cis-form 30a
–73.4)
(δ
P,–80
C
–80.1)
–90 ℃
(δP,–80
C
–74
–76
–78
–80
–70
–72
–74
M = Bi
25 ℃
M = Sb
25 ℃
0
℃
0
℃
–
–
–
10 ℃
–10 ℃
–20 ℃
–30 ℃
–40 ℃
–50 ℃
20 ℃
30 ℃
–40 ℃
–50 ℃
–60 ℃
–70 ℃
trans-form 31b
(
δ
P,–40
C
–55.2)
–60 ℃
trans-form 32b
–12.8)
(δP,–60
C
–70 ℃
–
80 ℃
90 ℃
–
80 ℃
cis-form 31a
P,–80
cis-form 32a
(
δ
C
–
–
(δP,–80
C
–
57.3)
–90 ℃
14.2)
–52
–54
–56
–58
–60
–14
–16
–18
–10
–12
31
1
FIGURE 3 VT- P{ H} NMR spectra of cis- and trans-1,2-oxaphosphetanes 25-32

8
of 17
UCHIYAMA et Al.
|
Group 14
Group 15
M
M
M
M
P
P
P
P
O
O
O
O
cis-form
trans-form
trans-form
cis-form
FIGURE 4 Optimized structures of 1,2-oxaphosphetanes bearing the phosphaheteratriptycene skeleton containing group 14 and 15 elements
signals of both trans- and cis-1,2-oxaphosphetanes were ob-
of 3.15-3.65 Å, which are much shorter than the sum of van
der Waals radii (2.00 Å for Si, 1.90 Å for P, 2.00 Å for As,
served only at −40°C and −90°C, respectively, in the presence
3
1
1
[27]
of lithium ions by VT- P{ H} NMR spectroscopy without
2.20 Å for Sb, and 2.40 Å for Bi). This suggests the pos-
[17]
any other intermediates. On the other hand, a broad signal
at −75.6 ppm was assigned to cis-1,2-oxaphosphetane 28a in
the n-butylphosphastannatriptycene systems that was formed
in the Wittig reaction of non-stabilized phosphonium ylide 20
with PhCHO under salt-free condition at −90°C. This was re-
sibility of interactions between the M and phosphorus atoms.
Phosphorus-31 chemical shifts of cis- and trans-1,2-
oxaphosphetanes bearing the phosphaheteratriptycene skele-
ton were observed within 2 ppm of each other, whereas those
of other phosphorus compounds were observed over a wider
chemical shift, depending on the heteroatom at the bridge-
head position of the phosphaheteratriptycene. Phosphorus-31
chemical shifts of 1,2-oxaphosphetanes with different het-
eroatoms were estimated by the GIAO method with an all
3
1
1
lated to another broad signal at −2.72 ppm in the VT- P{ H}
NMR spectra, which could be attributed to the reversible
change in an equilibrium at temperature between −40°C and
−
90°C. These results suggest that cis-1,2-oxaphosphetane
8a was in equilibrium with another species, such as an anti-
betaine intermediate.
[29–32]
2
electron basis set (DZP).
The calculated phosphorus-31
NMR chemical shifts did not agree accurately with the mea-
sured values, but the tendency of the signal to appear at lower
field as the row number increases was in good agreement
with the observed NMR results. The results showed that the
phosphorus-31 chemical shifts depended on the heteroatom
at the bridgehead position of the phosphaheteratriptycene.
On the other hand, the temperature of isomerization from cis-
1,2-oxaphosphetanes to their trans-forms seems to depend on
the readiness of the ring-opening reaction, because the isom-
erization is considered to occur via ring-opening and ring-
closing reactions of phosphonium ylides with PhCHO. In an
equilibrium between the 1,2-oxaphosphetanes and phospho-
nium ylides-PhCHO, the equilibrium inclines more toward
the right side because of the increase in stability of the phos-
phonium ylides.
2
.6
DFT calculations to obtain free
|
energies and phosphorus-31 chemical
shifts of 1,2-oxaphosphetanes bearing the
phosphaheteratriptycene skeleton
Density functional theory (DFT) calculations were car-
ried out for the 1,2-oxaphosphetanes bearing the phos-
phaheteratriptycene skeleton containing group 14 and 15
elements in order to estimate the optimized structures,
free energies at 298 K, and phosphorus-31 NMR chemical
shifts (Figure 4 and Table 4). The optimized structure was
confirmed by frequency analysis, which showed the global
[
28]
minimum structure due to zero imaginary frequency. In all
1
,2-oxaphosphetanes, the trans-forms are ~2 kcal/mol more
stable than the cis-forms because of the absence of steric
2
.7
Mechanism of isomerization from
|
hindrance between the methyl and phenyl groups at 3- and
cis-1,2-oxaphosphetane to trans-form in the
4
-positions. This is in good agreement with the results of VT-
Wittig reaction
3
1
1
P{ H} NMR spectroscopy. Phosphorus-31 signals reveal
that cis- and trans-1,2-oxaphosphetanes were the kinetic and
thermodynamic products, respectively. This is because, for
all the cases, the signals due to the cis-forms were observed
much earlier than those due to the trans-forms. Signals were
observed at the different temperatures depending on the het-
eroatom at the bridgehead position of the phosphaheteratrip-
tycene skeleton. M···P distances were found to be in the range
We have considered the mechanism of Wittig reactions of
non-stabilized phosphonium ylides with PhCHO based on
our previous results using the stibine derivative as shown in
Scheme 4. The reactions gave (Z)- and (E)-olefins, whose ra-
tios are highly dependent on the potential of the substituents
on the phosphorus atom, based on how much they can sta-
bilize the phosphorus ylide. In the phosphaheteratriptycene

UCHIYAMA et Al.
9 of 17
|
SCHEME 4 Plausible mechanism for Wittig reactions and isomerization from cis-1,2-oxaphosphetanes to trans-forms
system, the heteroatom at the bridgehead position induced
the stabilization of the non-stabilized phosphonium ylide;
similar results were observed for the tri-n-butylphosphine
with PhCHO and p-chlorobenzaldehyde at −40°C at the same
time, indicating the formation of the cross product. Therefore,
other phosphaheteratriptycenes are expected to behave similar
to the phosphastibatriptycene system. Since the cross product
was formed at the temperature of the isomerization, the equi-
librium of each phosphaheteratriptycene is considered to occur
at the observed temperature of isomerization.
[
3,6,20]
system as well.
The phosphonium ylides can be stabi-
lized by the negative charge on the carbon emerging from
+
−
the M(δ )–C(δ ) bond polarization, and its extent is de-
pendent on the electronegativity of the heteroatom; that is,
the ylide is more stabilized as the electronegativity of the
heteroatoms decreases. Indeed, the phosphaheteratriptycene
skeleton works as a tridentate ligand and electron-donating
aryl groups toward phosphorus atoms, which causes an up-
Although the equilibrium was not revealed to occur via
betaine intermediates or direct retro-[2 + 2] cycloaddition re-
action in this study, cis-1,2-oxaphosphetane 28a bearing the
phosphastannatriptycene skeleton was observed as a broad
3
1
1
field shift of phosphorus atom (δ −47.6 for 1, −47.7 for 2,
signal at from −90°C to −50°C in the VT- P{ H} NMR
spectra. Also, the signal was related to another broad signal
P
−
33.4 for 3, −30.8 for 4, −46.1 for 5, −34.5 for 6, and −10.1
3
1
1
for 7) toward the triphenylphosphine system (δ −5.39).
at a higher filed in the VT- P{ H} NMR spectra, which was
attributed a reversible change. Another species, such as an
anti-betaine intermediate (Scheme 4), could be considered in
the equilibrium based on the experimental results, although
cis-1,2-oxaphosphetanes bearing the phosphaheteratripty-
cene skeleton (observed as a sharp signal) might proceed via
a different pathway such as the retro-[2 + 2] cycloaddition
reaction.
P
This was similar to that observed for the n-butyl group in
the tri-n-butylphosphine system (δ −30.6), although phos-
P
phabismatriptycene 8 was observed at 12.5 ppm (Table 1).
As a result, isomerization from the cis-1,2-oxaphosphetanes
to the trans-forms occurs easily via phosphaheteratriptycene,
resulting in (E)-selective olefin formation.
The isomerization is derived from the equilibrium be-
tween 1,2-oxaphosphetane and the non-stabilized phospho-
nium ylide-PhCHO rather than the inversion at the α-carbon
[
33]
of the Schlosser type intermediate.
This was confirmed
3
CONCLUSION
|
based on the results of the crossover experiments of β-
hydroxyalkylphosphonium salt bearing the phosphastibatripty-
In this paper, the heteroatom effect of the phosphaheteratrip-
tycene skeleton toward the isomerization from the cis-1,2-
oxaphosphetanes to their trans-forms was described based on
[17]
cene skeleton in the presence of p-chlorobenzaldehyde. The
investigation showed both cis-1,2-oxaphosphetanes (δ −56.5
P
31
1
and −56.6) composed of non-stabilized phosphonium ylide
the results obtained from VT- P{ H} NMR spectroscopy,

1
0 of 17
UCHIYAMA et Al.
|
and supported by DFT calculations. The selectivity of (Z)/(E)-
olefins in the reaction was attributed to the readiness of the
isomerization of the intermediates derived from the equilibrium
between the 1,2-oxaphosphetanes and the non-stabilized phos-
phonium ylides-PhCHO. The heteroatom effect also induced
the upfield shift of phosphorus nuclei in the phosphahetera-
triptycene, as compared to that of the triphenylphosphine sys-
tem (except in the case of phosphabismatriptycene skeleton)
because of the M(δ )–C(δ ) polarization arising from elec-
tronegativity and low-field shift of phosphorus-31 signals of
the phosphaheteratriptycene skeleton as the row number of the
same group element increases. In the phosphastannatriptycene
system, it was shown that cis-1,2-oxaphosphetane 28a was
probably in equilibrium with another intermediate, such as a
from a 5 mL syringe at −90°C to −85°C for 5 min, to give
deep yellow clear solution through green solution. The reac-
tion mixture was stirred at −90°C for 30 min. A THF (15 mL)
solution of MCl (M = PhSi, PhGe, PhSn, n-BuSn, P, As, Sb,
3
and Bi) was added to the reaction mixture at −90°C to −85°C
for 10 min by a Teflon transfer tube from 50-mL two-neck
round-bottom flask, and the mixture was stirred for 1 hour
at the same temperature. Evaporation of the solvent, THF,
was performed before treatment of the mixture with aqueous
NH Cl (40 mL) and the extraction with CHCl (40 mL × 3).
+
−
4
3
The organic layer was washed with water (40 mL) and aque-
ous NaCl (40 mL) and dried over MgSO . The treated organic
4
solution was evaporated to give a yellow solid, and then, the
solid was filtrated with AcOEt-hexane in a ratio of 1:1. The
filtrate was evaporated after removing white polymer, and the
residue was washed with acetone to give phosphaheteratrip-
tycenes 1-8 as a white solid.
3
1
1
betaine, as concluded from the broad signal in the VT- P{ H}
NMR spectra. Thus, the interesting phenomena observed in the
Wittig reaction of non-stabilized phosphonium ylides bearing
the phosphaheteratriptycene skeleton with PhCHO prompt us
to further investigate their detailed mechanism.
2,3,6,7,14,15-Hexamethyl-10-Phenyl-9-phospha-10-
1
silatriptycene 1: White solid [m.p 269.5~272.3°C], H NMR
(
600 MHz, CDCl ) δ = 2.15 (9H, s), 2.19 (9H, s), 7.47 (3H,
3
1
3
1
s), 7.69-7.71 (6H, m), 8.26-8.27 (2H, m), C{ H} NMR
4
EXPERIMENTAL SECTION
General
|
(
151 MHz, CDCl ) δ = 19.51 (p), 19.52 (p), 128.2 (q), 128.7
3
2
(
t), 130.7 (t), 134.4 (t), 135.91 (q), 136.1 (q, J = 46.5 Hz),
CP
4
.1
|
3
4
1
36.2 (t, J = 15.1 Hz), 136.4 (t), 139.5 (q, J = 2.11 Hz),
CP CP
1
13
1
31
1
3
31
1
H, C{ H}, and P{ H} NMR spectra were recorded by
144.7 (q, J = 6.49 Hz), P{ H} NMR (243 MHz, CDCl )
CP
3
2
9
1
Bruker Advance-III or Bruker Advance-II 600 (600 MHz for
δ = −47.7(s), Si{ H} NMR (119 MHz, CDCl ) δ = −38.9
3
1
13
31
29
3
H, 151 MHz for C, 243 MHz for P, 119 MHz for Si
(d, J = 7.15 Hz), ESI-MS [CH CN]: Found: m/z 449.1842,
SiP
3
1
19
and 224 MHz for Sn) spectrometer at room temperature as
Calcd for C H PSi+H: 449.1849.
30 29
the inner standards of TMS (δ 0.00), acetone-d (δ 2.06),
2,3,6,7,14,15-Hexamethyl-10-phenyl-9-phospha-10-
H
6
H
1
CDCl (δ 77.0), H PO (δ 0.00), TMS (δ 0.00), and n-
germatriptycene 2: White solid [m.p 295.8~298.3°C], H
3
C
3
4
P
Si
Bu Sn (δ 0.00). Melting points were measured by Yanaco
NMR (600 MHz, CDCl ) δ = 2.16 (9H, s), 2.19 (9H, s), 7.47
4
Sn
3
3
micro-melting point apparatus. ESI-MS spectroscopy was
conducted by Exactive Plus of Thermo Fisher Co. X-ray
crystallographic analysis was performed by SMART APEX
II of Bruker AXS Co. Reagents and solvents for synthesis
were purchased from Nacalai Tesque, Kanto Chemical Co.,
INC., Wako Pure Chemical Industries, Ltd., Sigma-Aldrich
Co. LLC., Cambridge Isotope Laboratories, Alfa Aesar, and
(3H, s), 7.65-7.71 (3H, m), 7.73 (3H, d, J = 12.0 Hz), 8.12-
PH
1
3
1
8.14 (2H, m), C{ H} NMR (151 MHz, CDCl ) δ = 19.48
3
(p), 129.1 (t), 130.1 (t), 130.4 (q), 133.5 (t), 136.0 (t), 136.0
1
2
(q), 136.1 (q, J = 38.0 Hz), 136.7 (t, J = 49.7 Hz),
PC
PC
3
4
31
1
141.4 (q, J = 6.79 Hz), 142.6 (q, J = 1.66 Hz), P{ H}
PC
PC
NMR (243 MHz, CDCl ) δ = −47.7 (s), ESI-MS [CH CN]:
3
3
Found: m/z 495.1287, Calcd for C H PGe+H: 495.1291.
3
0
29
MERCK. 1.58-1.60 M (TMS) NNa in THF made in KANTO
2,3,6,7,14,15-Hexamethyl-10-phenyl-9-phospha-10-
2
was used for the generation of non-stabilized phosphonium
stannatriptycene 3: White solid [m.p 305.1~307.9°C],
1
ylides. Dried THF and Et O were used from the solvent cans
H
NMR (600 MHz, CDCl ) δ = 2.17 (9H, s,
2
3
4
5
of KANTO without any further purification.
J
= 116.4 Hz), 2.19 (9H, s, J = 109.8 Hz), 7.52 (3H,
SnH
SnH
3
s, J = 43.8 Hz), 7.58-7.61 (1H, m), 7.64-7.66 (2H, m),
SnH
3
4
7
(
.81 (3H, d, J = 13.8 Hz,
J
= 18.0 Hz), 7.98-8.00
PH
SnH
4
9
.2
Synthesis of 2,3,6,7,14,15-hexamethyl-
|
3
13
1
2H, m, J = 54.6 Hz), C{ H} NMR (151 MHz, CDCl )
SnH 3
-phospha-10-heteratriptycenes
2
δ = 19.3 (p), 19.5 (p), 129.5 (t, J = 59.5 Hz), 130.2 (t,
SnC
4
J
= 13.0 Hz), 132.9 (q), 136.3 (q), 136.4 (q), 136.4 (t,
SnC
4
.2.1 General process
|
3
3
4
2
3
JPC = 16.6 Hz, J = 9.66 Hz), 137.9 (t, J = 53.0 Hz,
SnC
PC
3
Under nitrogen, to a THF (100 mL) solution of tris(2-bromo-
JSnC = 16.9 Hz), 138.1 (t,
J
= 39.1 Hz), 142.2 (q,
SnC
31
1
4
,5-dimethylphenyl)phosphine (1.00 g, 1.72 mmol) in 200-mL
JCP = 8.60 Hz), 145.2 (q), P{ H} NMR (243 MHz, CDCl )
3
3
119
1
three-necked round flask with a −100 ~ 50°C thermometer and
δ = −33.4 (t,
J
= 64 Hz),
Sn{ H}NMR (224 MHz,
PSn
3
a septa was added 1.60 M pentane solution of t-BuLi (4.2 mL,
6
CDCl ) δ = −256 (d, J = 65 Hz), ESI-MS [CH CN]:
3
PSn
3
.72 mmol, 3.9 equivalent toward the starting triarylphosphine)
Found: m/z 541.1098, Calcd for C H PSn+H : 541.1102.
30 29

UCHIYAMA et Al.
11 of 17
|
1
0-n-Butyl-2,3,6,7,14,15-hexamethyl-9-phos-
mixture before the reaction solvent was completely evapo-
rated under the reflux condition. The reaction mixture was
evaporated after the stirring and the residue was filtrated with
THF to give a pale yellow solid of ethylphosphonium iodides
9-16.
1
pha-10-stannatriptycene 4: colorless oil,
H NMR
3
(
600 MHz, CDCl ) δ = 1.11 (3H, t, J = 7.2 Hz), 1.70-
3
HH
1
2
7
.74 (2H, m), 2.06-2.14 (2H, m), 2.19-2.31 (2H, m),
3
.16 (9H, s), 2.17 (9H, s), 7.44 (3H, s, J = 41.4 Hz),
SnH
3
4
13
1
.78 (3H, d,
J
= 13.2 Hz,
J
= 14.4 Hz), C{ H}
9-Ethyl-2,3,6,7,14,15-hexamethyl-10-phenyl-9-
PH
SnH
2
NMR (151 MHz, CDCl ) δ = 8.54 (s, J = 428.1 Hz),
phosphonio-10-silatriptycene iodide 9: White solid [m.p.
3
SnC
5
1
1
3.80 (p,
J
= 12.9 Hz), 19.37 (p), 19.43 (p), 27.62
307.0-309.0°C], H NMR (600 MHz, CDCl ) δ = 2.18 (3H,
SnC
3
3
4
3
3
(
s,
J
= 55.7 Hz), 29.19 (s,
J
= 29.4 Hz), 136.05
dt, J = 19.8 Hz, J = 7.2 Hz), 2.25 (9H, s), 2.36 (9H,
SnC
SnC
= 8.22 Hz),
PH HH
1
2
2
3
(
q,
JPC = 21.8 Hz,
J
136.09
(q,
s), 4.26 (2H, dq, J = 13.8 Hz, J = 7.8 Hz), 7.60 (3H,
PH HH
SnC
4
3
3
4
3
JPC = 7.28 Hz, J = 8.22 Hz), 136.5 (t, J = 1.66 Hz,
d, J = 3.6 Hz), 7.80 (2H, tm, J = 7.2 Hz), 7.84 (1H,
HH HH
SnC
PC
2
2
3
3
3
JSnC = 42.6 Hz), 137.7 (t, J = 53.0 Hz, J = 29.9 Hz),
tm, J = 7.2 Hz), 8.02 (3H, d, J = 12.0 Hz), 8.20 (2H,
HH PH
PC
SnC
3
4
3
13
1
1
42.2 (q,
SnC
J
= 7.55 Hz,
J
= 10.9 Hz), 146.2 (q,
P{ H} NMR (243 MHz, CDCl )
dm, JHH = 7.2 Hz), C{ H} NMR (151 MHz, CDCl )
3
PC
SnC
1
31
1
2
1
J
= 452.0 Hz),
δ = 7.90 (p,
J
= 6.20 Hz), 7.95 (s,
J
= 32.0 Hz),
3
PC
PC
3
119
1
1
δ = −30.8 (t, J = 50.0 Hz), Sn{ H}NMR (224 MHz,
122.3 (q), 127.2 (q, J = 82.4 Hz), 129.6 (t), 131.5 (t,
PSn
PC
3
2
4
CDCl ) δ = −217.5 (d, J = 48.8 Hz), ESI-MS [CH CN]:
J
= 10.9 Hz), 132.5 (t), 135.3 (t, J = 1.8 Hz), 136.3
3
PSn
3
PC
PC
1
3
Found: m/z 521.1417, Calcd for C H PSn : 521.1415.
(t), 138.8 (q,
J
= 29.9 Hz), 138.9 (q,
J
= 7.8 Hz),
2
8
34
PC
PC
4
31
1
2
,3,6,7,14,15-hexamethyl-9,10-diphosphatriptycene 5:
140 (q, J = 3.17 Hz), P{ H} NMR (243 MHz, CDCl )
PC
3
[
25]
1
29
1
White solid [m.p. 340.0~343.0°C, lit >300°C], H NMR
δ = −6.15 (s), Si{ H} NMR (119 MHz, CDCl ) δ = −40.1
3
3
(
600 MHz, CDCl ) δ = 2.18 (18H, s), 7.66-7.70 (6H, m),
(d, J = 56.6 Hz), ESI-MS [CH CN]: Found: m/z 495.2262,
3
PSi
3
3
1
1
P{ H} NMR (243 MHz, CDCl ) δ = −45.3 (s), ESI-MS
Calcd for C H PSi+H O: 495.2268.
3
32 34 2
[
CH CN] Anal.: 375.1426, Calcd for C H P +H: 375.1426.
9-Ethyl-2,3,6,7,14,15-hexamethyl-10-phenyl-9-
3
2
24 24 2
, 3 , 6 , 7 , 1 4 , 1 5 - H e x a m e t hyl - 9 - p h o s p h a - 1 0 -
phosphonio-10-germatriptycene iodide 10: White solid
1
1
arsatriptycene 6: White solid [m.p. 364~368°C],
H
[m.p. 330.8~331.8°C], H NMR (600 MHz, CDCl ) δ = 2.19
3
3
3
NMR (600 MHz, CDCl ) δ = 2.19 (18H, s), 7.67 (3H, s),
(3H, dt, J = 19.2 Hz, J = 7.8 Hz), 2.25 (9H, s), 2.36
3
PH
HH
3
13
1
2
3
7
.75 (3H, d, J = 10.8 Hz), C { H} NMR (151 MHz,
(9H, s), 4.27 (2H, dq, JPH = 13.8 Hz,
J
= 7.8 Hz),
PH
HH
3
4
CDCl ) δ = 19.4 (p), 134.7 (t, J = 1.81 Hz), 135.9 (t,
7.60 (3H, d, J = 3.6 Hz), 7.78-7.80 (3H, m), 8.03 (3H,
3
PC
PH
2
1
3
13
1
J
= 46.5 Hz), 136.5 (q, J = 14.3 Hz), 136.6 (q), 140.1
d,
J
= 12.0 Hz), 8.06-8.07 (2H, m), C{ H} NMR
PC
PC
PH
3
4
31
2
(
(
q,
J
= 5.1 Hz), 146.4 (q,
J
= 3.2 Hz), P NMR
(151 MHz, CDCl ) δ = 7.99 (p,
J
= 5.7 Hz), 8.20 (s,
PC
PC
3
PC
1
243 MHz, CDCl ) δ = −34.55 (s), ESI-MS [CH CN]:
J
= 48.2 Hz), 124,4 (q), 124.9 (q), 130.0 (t), 131.8 (t),
3
3
PC
3
3
Found: m/z 419.0903, Calcd for C H AsP+H: 419.0904.
132.0 (t, J = 11.0 Hz), 134.5 (t, J = 11.8 Hz), 135.7 (t),
2
4
24
PC PC
3
3
2
, 3 , 6 , 7 , 1 4 , 1 5 - H e x a m e t hyl - 9 - p h o s p h a - 1 0 -
138.8 (q, J = 12.5 Hz), 140.9 (q, J = 3.0 Hz), 142.2 (q,
PC PC
[17]
1
31
1
stibatriptycene 7: White solid [m.p. 295~300°C, lit
J
= 8.5 Hz), P{ H} NMR (243 MHz, CDCl ) δ = −9.06
P
C
3
1
>
257~258°C], H NMR (600 MHz, CDCl ) δ = 2.18 (s, 9H,
(s), ESI-MS [CH CN]: Found: m/z 523.1613, Calcd for
3
3
3
CH ), 2.19 (s, 9H, CH ), 7.69 (s, 3H), 7.90 (d, J = 12.0 Hz,
C H PGe: 523.1604.
3
3
PH
32 34
3
1
1
3
H), P{ H} NMR (CDCl , 243 MHz) δ = −10.8 (s).
9-Ethyl-2,3,6,7,14,15-hexamethyl-10-phenyl-9-
3
2
,3,6,7,14,15-Hexamethyl-9-phospha-10-bismatriptycene
phosphonio-10-stannatriptycene iodide 11: White solid
1
1
8
: White solid [m.p. 293~297°C], H NMR (600 MHz, CDCl )
[m.p. 267.5~269.8°C], H NMR (600 MHz, CDCl ) δ = 2.16
3
3
3
3
δ = 2.17 (9H, s), 2.18 (9H, s), 7.86 (3H, s), 8.29 (3H, d,
(3H, dt, J = 18.0 Hz, J = 7.8 Hz), 2.26 (9H, s), 2.37
PH
HH
3
13
1
2
3
J
= 12.0 Hz), C { H} NMR (151 MHz, CDCl ) δ = 19.2
(9H, s), 4.21 (2H, dq, JPH = 13.8 Hz,
J
= 7.2 Hz),
PH
3
HH
1
2
4
3
(
p), 19.5 (p), 135.5 (t, J = 53.7 Hz), 136.7(q, J = 16.5 Hz),
7.65 (3H, d,
J
= 3.6 Hz,
J
= 45.0 Hz), 7.70-7.77
PC
PC
PH
SnH
3
2
3
1
37.3 (q,
J
= 1.51 Hz), 138.4 (t,
J
= 2.1 Hz), 141.5
(3H, m), 7.93-7.95 (2H, m), 8.03 (3H, d, J = 12.0 Hz,
PC
PC
PH
3
31
4
13
1
(
q, J = 5.3 Hz), 163.4 (q), P NMR (162 MHz, CDCl )
J
= 20.4 Hz), C{ H} NMR (151 MHz, CDCl ) δ = 8.6
PC
3
SnH
3
3
2
1
δ = 12.50 (q, J = 12.2 Hz), ESI-MS [CH CN]: Found: m/z:
(p, J = 5.59 Hz), 8.8 (s, J = 49.5 Hz), 19.8 (p), 19.9
PH
3
PC
PC
1
4
5
53.1494, Calcd for C H BiP+H: 553.1492.
(p), 126.0 (q, J = 84.8 Hz), 127.7 (q, J = 4.38 Hz),
24
24
PC
PH
3
3
1
30.4 (t, J = 69.2 Hz), 131.8 (t), 132.7 (t, J = 12.2 Hz,
SnC PC
3
3
2
J
= 28.2 Hz), 137.4 (t, J = 12.7 Hz, J = 27.3 Hz),
PC SnC
SnC
37.9 (t,
4
.3
Synthesis of 9-ethyl-2,3,6,7,14,15-
|
2
3
1
J
= 43.3 Hz), 139.0 (q, JPC = 13.3 Hz),
SnC
hexamethyl-9-phosphonio-10-
heteratriptycene iodide
3
3
1
41.0 (q, JPC = 3.17 Hz,
J
= 45.3 Hz), 145.0 (q,
SnC
2
31
1
J
= 10.1 Hz),
P { H} NMR (243 MHz, CDCl )
PC
3
3
119
1
Under nitrogen, a CHCl (5 mL) solution of phosphahetera-
triptycenes 1-8 and ethyl iodide (40 μL, 0.500 mmol) was
δ = −7.79 (t, J = 302.4 Hz), Sn{ H} NMR (224 MHz,
3
SnP
3
CDCl ) δ = −267.7 (d, J = 302.6 Hz), ESI-MS [CH CN]:
3
SnP
3
heated at 70°C. CHCl (2 mL) was added to the reaction
Found: m/z 569.1418, Calcd for C H PSn: 569.1415.
3
32 34

1
2 of 17
UCHIYAMA et Al.
|
1
0-n-Butyl-9-ethyl-2,3,6,7,14,15-hexamethyl-9-phos-
9-Ethyl-2,3,6,7,14,15-hexamethyl-9-phosphonio-
phonio-10-stannatriptycene iodide 12: white solid [de-
10-bismatriptycene iodide 16: pale yellow solid [m.p.
1
1
comp. 153~158°C], H NMR (600 MHz, CDCl ) δ = 1.15
293~295°C (decomp.)], H NMR (600 MHz, CDCl )
3
3
3
3
3
(
3H, t, J = 7.2 Hz), 1,70-1.75 (2H, m), 2.12 (3H, dt,
δ = 2.13 (3H, dt,
J
= 17.6 Hz,
(9H, s), 2.29 (9H, s), 3.81 (2H, dq,
J
= 7.52 Hz), 2.27
HH
PH
HH
3
3
2
J
= 18.6 Hz,
J
= 7.2 Hz), 2.18-2.21 (2H, m), 2.26
J
= 13.5 Hz,
PH
HH
PH
3
3
4
3
(
9H, s), 2.33 (9H, s), 2.43 (2H, t, J = 7.2 Hz), 4.09
J
= 7.59 Hz), 8.11 (3H, d, J = 10.2 Hz), 8.29 (3H, d,
HH
HH PH
2
3
13
1
(
2H, dq,
J
= 13.2 Hz,
J
= 7.2 Hz), 7.61 (3H, d,
J
= 3.0 Hz), C{ H} NMR (151 MHz, CDCl ) δ = 7.67
PH
HH
PH
3
3
4
3
3
2
J
= 3.6 Hz, J = 46.2 Hz), 7.93 (3H, d, J = 12.0 Hz,
(p, J = 5.74 Hz), 10.6 (s, J = 49.7 Hz), 19.73 (p), 19.92
PH
SnH
PH
PC
PC
4
13
1
1
2
JSnH = 15.0 Hz),
C{ H} NMR (151 MHz, CDCl )
(p), 122.8 (t,
J
= 94.6 Hz), 131.6(q,
J
= 14.3 Hz),
3
PC
PC
2
1
3
3
δ = 8.28 (p, J = 5.89 Hz), 9.05 (s, J = 50.0 Hz), 10.9
138.2 (q, J = 12.2 Hz), 139.2 (t, J = 12.2 Hz), 142.3
PC
PC
PC
PC
4
4
31
(
s, J = 3.17 Hz), 13.7 (t), 19.8 (p), 19.9 (p), 27.7 (s),
(q, J = 3.62 Hz), 159.0 (q), P NMR (162 MHz, CDCl )
PC
P
C
3
1
3
2
8.7 (s), 126.0 (q, J = 85.2 Hz), 132.3 (t, J = 12.8 Hz,
δ = 54.4 (s), ESI-MS [CH CN]: Found: m/z 581.1807, Calcd
PC
PC
3
3
2
J
= 26.4 Hz), 137.6 (t,
J
= 13.0 Hz), 138.5 (q,
for C H Bi: 581.1805.
SnC
SnC
26 29
3
2
3
JPC = 13.0 Hz), 140.7 (q, JPC = 3.17 Hz), 146.1 (q,
JPC = 10.3 Hz),
31
1
P
{ H} NMR (243 MHz, CDCl )
3
4
.4
Data of 2,3,6,7,14,15-Hexamethyl-9-
3
119
1
|
δ = −7.37 (t, J = 237.9 Hz), Sn{ H} NMR (224 MHz,
SnP
phospha-10-heteratriptycene 9-oxide
3
CDCl ) δ = −232.3 (d, J = 257.4 Hz), ESI-MS [CH CN]:
3
SnP
3
Found: m/z 549.1734, Calcd for C H PSn: 549.1728.
Phosphaheteratriptycene oxides were purified from the crude
materials, which were obtained by Wittig reactions of non-
stabilized phosphonium ylides bearing a phosphaheteratrip-
tycene skeleton with benzaldehyde, by the following method.
The crude materials were obtained by evaporation of THF
as a reaction solvent and filtrated with a membrane together
with 3 mL of CHCl . The CHCl solution was introduced to
3
0
38
9
-Ethyl-2,3,6,7,14,15-hexamethyl-9-phosphonio-
1
0-phosphphatriptycene iodide 13: Pale yellow solid
1
[
(
(
(
m.p.342.5~343.5°C], H NMR (600 MHz, CDCl ) δ = 2.15
3
3
3
3H, dt, J = 19.8 Hz, J = 7.2 Hz), 2.28 (9H, s), 2.35
PH
HH
2
3
9H, s), 4.29 (2H, dq, J = 9.00 Hz, J = 7.8 Hz), 7.80
PH
HH
3
4
3
3H, dd, J = 6.6 Hz, J = 4.2 Hz), 8.04 (3H, d, J =
PH
HH
PH
3
3
1
3
1
1
1.4 Hz), C{ H} NMR (151 MHz, CDCl ) δ = 7.49 (p,
a 908 gel permeation chromatography (GPC) and separated
a few fraction to get a fraction containing a target phosphine
oxide with a retention time at 45-50 min. The obtained frac-
tion was separated by preparative thin layer chromatography
(PTLC) to get a pure target phosphine oxide.
3
2
1
J
= 7.35 Hz), 7.90 (s,
J
= 46.3 Hz), 19.7 (p), 19.8
PC
PC
1
2
(
p), 124.8 (q, J = 74.7 Hz), 132.1 (t, J = 11.1 Hz),
PC
PC
2
3
1
36.8 (t,
J
= 33.7 Hz,
J
= 8.55 Hz), 139.4 (q,
PC
PC
3
1
2
J
= 12.3 Hz), 140.7 (q, J = 21.1 Hz, J = 10.2 Hz),
PC
PC
PC
3
31
1
1
41.6 (q, J = 13.4 Hz), P { H}NMR (243 MHz, CDCl )
2,3,6,7,14,15-Hexamethyl-10-phenyl-9-phospha-10-
silatriptycene 9-oxide 33: compound 33 decomposed during
its purification because of unstable in the air.
PC
3
δ = −2.56 (s), −59.8 (s), ESI-MS [CH CN]: Found: m/z
3
4
03.1742, Calcd for C H P : 403.1739.
26 29 2
9
-Ethyl-2,3,6,7,14,15-hexamethyl-9-phosphonio-
2,3,6,7,14,15-Hexamethyl-10-phenyl-9-phospha-10-
1
0-arsatriptycene iodide 14: Pale yellow solid [m.p.
germatriptycene 9-oxide 34: Pale yellow solid [decomp.
1
1
3
31~334°C], H NMR (600 MHz, CDCl ) δ = 2.17 (3H, dt,
313.0~314.5°C], H NMR (600 MHz, CDCl ) δ = 2.20
3
3
3
3
4
J = 19.2 Hz, J = 7.8 Hz), 2.28 (9H, s), 2.36 (9H, s),
(9H, s), 2.25 (9H, s), 7.48 (3H, d, J = 3.6 Hz), 7.69-
PH
HH
PH
2
3
2
4
.27 (2H, dq, J = 13.8 Hz, J = 7.2 Hz), 7.79 (3H, d,
7.74 (3H, m), 8.04 (3H, d, J = 12.0 Hz), 8.07-8.09
PH
HH
PH
4
3
13
1
13
1
J = 4.2 Hz), 8.05 (3H, d, J = 10.8 Hz), C{ H} NMR
(2H, m), C{ H} NMR (151 MHz, CDCl ) δ = 19.5 (p),
PH
PH
3
2
4
(
151 MHz, CDCl ) δ = 7.62 (p, J = 5.74 Hz), 8.34 (s,
19.7 (p), 127.4 (q, J = 3.17 Hz), 129.4 (t), 130.8 (t),
3
PC
PC
1
1
2
3
J
= 47.4 Hz), 19.8 (p), 19.9 (p), 122.1 (q, J = 91.7 Hz),
131.0 (t, J = 7.7 Hz), 133.0 (t, J = 12 Hz), 134.5
PC
PC
PC PC
2
3
1
1
32.2 (t, J = 12.8 Hz), 135.9 (t, J = 9.21 Hz), 139.3
(q), 135.94 (t), 135.97 (q, J = 100.1 Hz), 136.8 (q,
PC
PC
PC
3
4
3
4
2
(
q, J = 12.1 Hz), 141.5 (q, J = 2.57 Hz), 143.8 (q,
J
= 11.5 Hz), 137.7 (q, J = 2.3 Hz), 142.2 (q, J
PC
PC
PC PC PC
2
31
1
31
1
J
= 6.95 Hz), P { H}NMR (243 MHz, CDCl ) δ = 1.32
=12.4 Hz), P{ H} NMR (243 MHz, CDCl ) δ = 1.65
PC
3
3
(
s), ESI-MS [CH CN]: Found: m/z 447.1214, Calcd for
(s), ESI-MS [CH CN]: Found: m/z 511.1241, Calcd for
3
3
C H AsP: 447.1217.
C H GeOP+H: 511.1241.
2
6
29
30 29
9
-Ethyl-2,3,6,7,14,15-hexamethyl-9-phosphonio-
2,3,6,7,14,15-Hexamethyl-10-phenyl-9-phospha-
1
0-stibatriptycene iodide 15: Pale yellow solid [m.p.
10-stannatriptycene 9-oxide 35: White solid [m.p
1
7]
1
1
2
38~341°C, lit m.p. 237~241°C], H NMR (600 MHz,
305.1~307.9°C], H NMR (600 MHz, CDCl ) δ = 2.21
3
3
3
4
CDCl ) δ = 2.16 (dt, J = 18.6 Hz, J = 7.2 Hz, 3H,
(9H, s), 2.26 (9H, s), 7.54 (3H, d,
J
= 3.60 Hz),
3
PH
HH
PH
H ), 2.27 (s, 9H, H ), 2.36 (s, 9H, H ), 2.36 (s, 9H, H ),
7.64-7.69 (3H, m), 7.94-7.75 (2H, m), 8.14 (3H, d,
Et
Me
Me
Me
2
3
3
4
13
1
4
.20 (dq, J = 13.2 Hz, J = 7.6 Hz, 2H, H ), 7.85 (d,
J
= 11.4 Hz,
J = 19.8 Hz),
SnH
C{ H}
NMR
PH
HH
Et
PH
4
3
J
= 3.6 Hz, 3H, 4,5,16-H), 8.01 (d, J = 10.8 Hz, 3H,
(151 MHz, CDCl ) δ = 19.48 (p), 19.54 (p), 129.8 (t), 130.8
3
PH
PH
3
1
1
2
3
1
,8,13-H), P{ H} NMR (243 MHz, CDCl ) δ = 12.2 (s).
(t), 131.9 (t, J = 8.15 Hz), 136.00 (t, J = 13.4 Hz),
PC PC
3

UCHIYAMA et Al.
13 of 17
|
1
1
36.01 (q), 137.0 (q), 137.3 (q, J = 90.1 Hz), 137.9
PC
4
.5
The Wittig reactions of non-stabilized
4
31
1
|
(
q, J = 3.02 Hz), 138.2 (t), 144.2 (q), P{ H} NMR
PC
phosphonium ylides with PhCHO at
3
(
242 MHz, CDCl ) δ = 1.99 (t,
JPSn = 305.1 Hz),
31
1
3
−
90°C and VT- P{ H} NMR spectroscopy
1
19
1
Sn{ H} NMR (223 MHz, CDCl ) δ = -282.9 (d,
3
3J = 315.1 Hz), ESI-MS [CH CN]: Found: m/z
5
Ethylphosphonium salts 9-16 in THF (0.5 mL) as a reaction sol-
PSn
3
57.1056, Calcd for C H OPSn : 557.1051.
vent were placed in a J-Young NMR tube with a sealed capillary
3
0
29
1
31
1
0-n-Butyl-2,3,6,7,14,15-hexamethyl-9-phos-
tube filled with acetone-d6 as a lock solvent for H and P NMR
measurement. To a suspension of 9-16 in THF in the NMR tube
was added (TMS)2NNa at 0°C to generate non-stabilized phos-
phonium ylides 17-24 making the solution yellow. The phos-
phonium ylides 17-24 were reacted with PhCHO at −90°C.
pha-10-stannatriptycene 9-oxide 36: White solid [m.p.
1
2
89~292°C (decomp.)], H NMR (600 MHz, CDCl )
3
2
δ = 1.12 (3H, t, J = 7.2 Hz), 1.69-1.74 (2H, m), 2.10-
HH
2
.25 (2H, m), 2.21 (9H, s), 2.23 (9H, s), 2.29-2.30 (2H,
4
4
31
1
m), 7.45 (3H, dt, J = 3.60 Hz, J = 14.0 Hz), 8.09
VT- P{ H} NMR spectra of the reaction mixture were meas-
ured every 10°C from −90°C to 25°C by accumulation on 128
of scan number after the addition of PhCHO to THF solution
at −90°C. The measurements at each target temperature were
performed after ca. 5 min for getting the constant temperature
by the thermo-monitor in an NMR equipment. The mixture was
allowed to warm to room temperature for over 3 hours. Yields
were estimated by using a singlet signal due to the methylene
protons of Ph2C=CH2 in THF (0.1 mL) as an internal standard
PH
SnH
3
4
31
1
(
(
3H, dt, J = 11.4 Hz, J = 11.4 Hz), P{ H} NMR
PH SnH
3
119
1
242 MHz, CDCl ) δ = 3.61 (t, J = 267.0 Hz), Sn{ H}
3
PSn
3
NMR (223 MHz, CDCl ) δ = −249.4 (d, J = 266.0 Hz),
3
PSn
ESI-MS [CH CN]: Found: m/z 537.1367, Calcd for
3
C H OPSn+H: 537.1364.
2
8
33
2
,3,6,7,14,15-Hexamethyl-9,10-diphosphatriptycene
1
9
-oxide 37: Pale yellow solid [decomp. 325~330°C], H
NMR (600 MHz, CDCl ) δ = 2.26 (9H, s), 2.25 (9H, s),
3
3
4
1
7.62 (3H, dd,
d,
J
= 10.8 Hz,
J
= 4.8 Hz), 7.90 (3H,
in H NMR spectroscopy after the confirmation of no change of
PH
PH
3
13
1
J
= 11.4 Hz), C{ H} NMR (151 MHz, CDCl )
the spectra in the Wittig reaction for over 12 hours.
PH
3
2
δ = 19.5 (p), 19.6 (p), 130.9 (t, J = 8.0 Hz), 134.7 (q,
PC
1
1
2
J
= 105.5 Hz), 135.5 (t, J = 41.4 Hz, J = 9.21 Hz),
(1) 17 + PhCHO: ethylphosphonium iodide 9 bearing the
Si-phenylphosphasilatriptycene (10.4 mg, 17.2 μmol),
(TMS)2NNa (36 μL, 68 μmol), PhCHO (5.9 μL, 6.1 mg,
57.6 μmol), PhCH=CHCH3 (0.772 mg, 6.54 μmol)/
Ph2C=CH2 (2.21 mg, 12.3 μmol) = 0.531/1.00, Yield
38%, (Z):(E) = 62:38.
PC
PC
PC
3
3
1
37.5 (q,
PC
J
= 10.7 Hz), 138.2 (q, JPC = 13.4 Hz,
PC
4
2
3
J
= 2.27 Hz), 140.9 (q, J = 11.8 Hz, J = 9.60 Hz),
PC PC
3
1
3
P NMR (243 MHz, CDCl ) δ = −74.1 (d, J = 4.8 Hz),
3
PP
3
7
3
.97 (d, J = 5.1 Hz), ESI-MS [CH CN] : Found: m/z
PP 3
91.1383, Calcd for C H OP +H: 391.1375.
2
4
24
2
2
, 3 , 6 , 7 , 1 4 , 1 5 - H e x a m e t hyl - 9 - p h o s p h a - 1 0 -
(2) 18 + PhCHO: ethylphosphonium iodide 10 bearing the
arsatriptycene 9-oxide 38: White solid [decomp. 275-
Ge-phenylphosphagermatriptycene
(12.6 mg,
1
2
80°C], H NMR (600 MHz, CDCl ) δ = 2.23 (9H, s),
21.0 μmol), (TMS)2NNa (36 μL, 68 μmol), PhCHO
(5.9 μL, 6.1 mg, 57.6 μmol), PhCH=CHCH3 (1.78 mg,
15.1 μmol)/Ph2C=CH2(2.04 mg,11.3 μmol) = 1.34/1.00,
Yield 72%, (Z):(E) = 17:83.
3
4
2
.25 (9H, s), 7.60 (3H, d, J = 4.8 Hz), 7.95 (3H, d,
PH
3
13
1
J
= 10.8 Hz),
C{ H} NMR (151 MHz, CDCl )
PH
3
2
δ = 19.4 (p), 19.6 (p), 131.2 (t, J = 8.6 Hz), 132.0 (q,
PC
1
3
2
3
J
= 107.8 Hz), 134.7 (q,
J
= 10.1 Hz), 137.4 (q,
(3) 19 + PhCHO: ethylphosphonium iodide 11 bearing the
Sn-phenylphosphastannatriptycene (10.9 mg, 15.0 μmol),
(TMS)2NNa (36 μL, 68 μmol), PhCHO (5.9 μL, 6.1 mg,
57.6 μmol), PhCH=CHCH3 (0.602 mg, 5.1 μmol)/
Ph2C=CH2 (2.11 mg, 11.7 μmol) = 0.436/1.00, Yield
34%, (Z):(E) = 21:79.
PC
PC
JPC = 11.3 Hz), 138.2 (q, 4J = 2.27 Hz), 143.2 (q,
PC
31
JPC = 13.1 Hz), P NMR (243 MHz, CDCl ) δ = 12.1
3
(
s), ESI-MS [CH CN]: Found: m/z 435.0854, Calcd for
3
C H AsOP+H: 435.0853.
2
4
24
2
, 3 , 6 , 7 , 1 4 , 1 5 - H e x a m e t hyl - 9 - p h o s p h a - 1 0 -
stibatriptycene 9-oxide 39: Pale yellow solid [de-
(4) 20 + PhCHO: ethylphosphonium iodide 12 bearing the
1
7]
1
comp. 281~284°C, lit decomp. 284~285°C], H NMR
CDCl , 600 MHz) δ = 2.22 (s, 9H, CH ), 2.25 (s, 9H,
Sn-n-butylphosphastannatriptycene
(11.9 mg,
(
17.7 μmol), (TMS)2NNa (36 μL, 68 μmol), PhCHO
(5.9 μL, 6.1 mg, 57.6 μmol), PhCH=CHCH3 (0.940 mg,
3
3
4
CH ), 7.66 (d, J = 4.2 Hz, 3H, 4,5,16-H), 8.09 (d,
3
PH
3
31
1
J
= 10.8 Hz, 3H, 1,8,13-H), P{ H} NMR (CDCl ,
7.97 μmol)/Ph2C=CH2
(2.23 mg,
PH
3
2
43 MHz) δ = 22.7 (s).
2
12.3 μmol) = 0.633/1.00, Yield 45%, (Z):(E) = 26:74.
(5) 21 + PhCHO: ethylphosphonium iodide 13 bearing the
diphosphatriptycene (10.2 mg, 19.2 μmol), (TMS)2NNa
(36 μL, 68 μmol), PhCHO (5.9 μL, 6.1 mg, 57.6 μmol),
, 3 , 6 , 7 , 1 4 , 1 5 - H e x a m e t hyl - 9 - p h o s p h a - 1 0 -
1
bismatriptycene 9-oxide 40: White solid [m.p. >300°C], H
NMR (400 MHz, CDCl ) δ = 2.25 (9H, s), 2.27 (9H, s), 8.0
3
4
3
31
(
(
3H, d, J = 4.0 Hz), 8.40 (3H, d, J = 8.0 Hz), P NMR
PhCH=CHCH3
(2.05 mg, 11.4 μmol) = 0.252/1.00,
(Z):(E) = 51:49.
(0.340 mg,
2.88 μmol)/Ph2C=CH2
PH
PH
162 MHz, CDCl ) δ = 65.3 (s), ESI-MS [CH CN]: Found:
m/z 569.1446, Calcd for C H BiOP+H: 569.1441.
Yield 15%,
3
3
2
4
24

1
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UCHIYAMA et Al.
|
TABLE 3 Crystal data of
phenylphosphastannatriptycenes 3 and 11
3
11
M.F.
C H SnP
C H ISnP·2.5C H (benzene)
3
0
29
32 34
6
6
Formula weight
Temperature
Wavelength
Crystal system
Space group
a (Å)
b (Å)
c (Å)
α (°)
β (°)
539.19
120
0.71073
Monoclinic
890.42
120
0.71073
Triclinic
P-1
12.7444(14)
13.4628(15)
13.4777(15)
102.3488(15)
111.7726(13)
99.5412(15)
2019.8(4)
2
P21/c
9.8994(4)
11.646(5)
21.7943(10)
90
94.9660(5)
90
2503.33(19)
4
γ (°)
Volume (Å )
3
Z
Density (g/cm3)
Crystal size
Index ranges
1.431
1.464
0.50 × 0.43 × 0.33
−13 < =h<=9, −13 < =k<=15,
0.52 × 0.51 × 0.03
−16 < =h<=14,
−14 < =k<=18, −18 < =l<=17
−20 < =l<=29
Reflections collected
Data/parameters
GOF
14364
5882/295
1.041
11561
9014/458
1.036
R (all data)
wR2 (all data)
0.0219
0.0494
0.0377
0.0686
(
6) 22 + PhCHO: ethylphosphonium iodide 14 bearing the phos-
with PhCHO at 0°C. Yields were estimated by the same way
in the reaction at −90°C.
phaarsatriptycene (11.4 mg, 19.9 μmol), (TMS) NNa (36 μL,
2
6
8 μmol), PhCHO (5.9 μL, 6.1 mg, 57.6 μmol),
PhCH=CHCH (0.742 mg, 6.29 μmol)/Ph C=CH (2.38 mg,
(1) 17 + PhCHO: ethylphosphonium iodide 9 bearing the
Si-phenylphosphasilatriptycene (3.94 mg, 8.25 μmol),
3
2
2
1
3.2 μmol) = 0.477/1.00, Yield 32%, (Z):(E) = 35:65.
(
7) 23 + PhCHO: ethylphosphonium iodide 15 bearing the
(TMS) NNa (22 μL, 41 μmol), PhCHO (3.9 μL, 4.1 mg,
2
phosphastibatriptycene
(11.8 mg,
19.0 μmol),
38.4 μmol), PhCH=CHCH (0.459 mg, 3.89 μmol)/
3
(
TMS) NNa (36 μL, 68 μmol), PhCHO (5.9 μL, 6.1 mg,
Ph C=CH (2.24 mg, 12.4 μmol) = 0. 314/1.00, Yield
2
2
2
5
7.6 μmol), PhCH=CHCH (1.95 mg, 16.5 μmol)/
47%, (Z):(E) = 87:13.
3
Ph C=CH (1.70 mg, 9.44 μmol) = 1.75/1.00, Yield
(2) 18 + PhCHO: ethylphosphonium iodide 10 bearing the
2
2
[17–19]
8
7%, (Z):(E) = 13:87.
Ge-phenylphosphagermatriptycene
(3.53 mg,
(
8) 24 + PhCHO: ethylphosphonium iodide 16 bearing the
6.76 μmol), (TMS) NNa (22 μL, 41 μmol), PhCHO
2
phosphabismatriptycene
(10.0 mg,
14.1 μmol),
(3.9 μL, 4.1 mg, 38.4 μmol), PhCH=CHCH (0.435 mg,
3
(
TMS) NNa (30 μL, 57 μmol), PhCHO (5.9 μL, 6.1 mg,
3.69 μmol)/Ph C=CH
2
(2.05 mg,
2
2
5
7.6 μmol), PhCH=CHCH (0.698 mg, 5.92 μmol)/
14.9 μmol) = 0.324/1.00, Yield 55%, (Z):(E) = 22:78.
(3) 19 + PhCHO: ethylphosphonium iodide 11 bearing the
Sn-phenylphosphastannatriptycene (10.2 mg, 17.5 μmol),
3
Ph C=CH (2.20 mg, 12.2 μmol) = 0.485/1.00, Yield
2
2
4
2%, (Z):(E) = 26:74.
(
TMS) NNa (36 μL, 68 μmol), PhCHO (5.9 μL, 6.1 mg,
2
5
7.6 μmol), PhCH=CHCH (1.16 mg, 9.87 μmol)/
3
4
.6
The Wittig reactions of non-stabilized
|
Ph C=CH (2.09 mg, 11.6 μmol) = 0.850/1.00, Yield
2
2
phosphonium ylides with PhCHO at 0°C
5
5%, (Z):(E) = 12:88.
(4) 20 + PhCHO: ethylphosphonium iodide 12 bearing the
Sn-n-butylphosphastannatriptycene (10.5 mg,
15.6 μmol), (TMS) NNa (36 μL, 68 μmol), PhCHO
Ethylphosphonium salts 9-16 in THF (0.5 mL) in the NMR
tube were added (TMS) NNa at 0°C to generate non-
2
stabilized phosphonium ylides 17-24, which were reacted
2

UCHIYAMA et Al.
15 of 17
|
TABLE 4 Free energies and phosphorus-31 NMR chemical shifts of 1,2-oxaphosphetanes
M
Si (cis-form)
Si (trans-form)
P (cis-form)
P (trans-form)
Gat 298 K (hartree)a
−1979.378874
−1979.382149
−2.06
−1799.652164
−1799.655453
−2.06
0
ΔG (kcal/mol)
Imaginary Freq.
0
0
0
0
a
0
0
M–P (Å)
3.160
437.550
−67.7
3.164
434.458
−64.6
3.263
437.812
−59.5
3.269
435.305
−56.9
3
1P NMR (ppm)b
c
δ (from H PO )
P
3
4
δP (observation)
M
−81.8
−80.0
−80.1
−78.2
Ge (cis-form)
−1693.597771
0
Ge (trans-form)
−1693.601332
−2.23
As (cis-form)
−1464.383150
0
As (trans-form)
−1464.386524
−2.12
Gat 298 K (hartree)a
0
ΔG (kcal/mol)
Imaginary Freq.
a
0
0
0
0
M–P (Å)
3.204
441.709
−71.8
3.208
438.639
−68.8
3.364
435.245
−56.9
3.370
432.317
−54.0
3
1P NMR (ppm)b
c
δ (from H PO )
P
3
4
δP (observation)
M
−82.8
−81.0
−73.4
−71.3
Sn (cis-form)
−1693.178790
0
Sn (trans-form)
−1693.182383
−2.25
Sb (cis-form)
−1463.653813
0
Sb (trans-form)
−1463.657380
−2.24
Gat 298 K (hartree)a
0
ΔG (kcal/mol)
Imaginary Freq.
a
0
0
0
0
M–P (Å)
3.317
436.566
−66.7
3.321
434.574
−64.7
3.473
424.093
−45.7
3.437
421.413
−43.1
3
1P NMR (ppm)b
c
δ (from H PO )
P
3
4
δP (observation)
M
−76.2
−74.8
−57.3
−55.2
Pb (cis-form)
−1693.231692
0
Pb (trans-form)
−1693.235336
−2.29
Bi (cis-form)
−1463.691071
0
Bi (trans-form)
−1463.694594
−2.21
Gat 298 K (hartree)a
0
ΔG (kcal/mol)
Imaginary Freq.
a
0
0
0
0
M–P (Å)
3.358
437.253
−67.4
3.363
435.198
−65.3
3.559
397.738
−19.4
3.564
395.074
−16.7
3
1P NMR (ppm)b
c
δ (from H PO )
P
3
4
δP (observation)
No data
No data
−14.2
−12.8
a
Optimization and frequency analysis by B3LYP/6-31G(d) for C, H, Si, P, and O, lanl2dz for Ge, Sn, Pb, As, Sb, and Bi.
b
c
GIAO method for NMR by B3LYP/6-31G(d) for C, H, O, and P(1,2-oxaphosphetane), DZP for Si, Ge, Sn, Pb, P(bridgehead atom), As, Sb, and Bi.
The phosphorus-31 chemical shift standard; δ 369.885 for H PO .
P
3
4
(
5.9 μL, 6.1 mg, 57.6 μmol), PhCH=CHCH (0.864 mg,
PhCH=CHCH
(0.480 mg, 4.07 μmol)/Ph C=CH
2 2
3
3
7
1
.32 μmol)/Ph C=CH
(2.37 mg,
(2.05 mg,
(Z):(E) = 36:64.
(7) 23 + PhCHO: ethylphosphonium iodide 15 bearing the
14.9 μmol) = 0.272/1.00,
Yield
50%,
2
2
3.2 μmol) = 0.550/1.00, Yield 47%, (Z):(E) = 11:89.
(
5) 21 + PhCHO: ethylphosphonium iodide 13 bearing the
diphosphatriptycene (2.36 mg, 5.85 μmol), (TMS) NNa
phosphastibatriptycene
(10.9 mg,
17.6 μmol),
2
(
22 μL, 41 μmol), PhCHO (3.9 μL, 4.1 mg, 38.4 μmol),
(TMS) NNa (36 μL, 68 μmol), PhCHO (5.9 μL, 6.1 mg,
2
PhCH=CHCH
(0.396 mg, 3.36 μmol)/Ph C=CH
57.6 μmol), PhCH=CHCH (1.45 mg, 12.3 μmol)/
3
2
2
3
(
(
2.24 mg,
12.4 μmol) = 0.270/1.00,
Z):(E) = 48:52.
Yield
57%,
Ph C=CH (2.37 mg, 13.2 μmol) = 0.932/1.00, Yield
2
2
70%, (Z):(E) = 20:80.
(
6) 22 + PhCHO: ethylphosphonium iodide 14 bearing the
(8) 24 + PhCHO: ethylphosphonium iodide 16 bearing the
phosphaarsatriptycene(3.61 mg,8.07 μmol),(TMS) NNa
phosphabismatriptycene
(10.2 mg,
17.5 μmol),
2
(
22 μL, 41 μmol), PhCHO (3.9 μL, 4.1 mg, 38.4 μmol),
(TMS) NNa (36 μL, 68 μmol), PhCHO (5.9 μL, 6.1 mg,
2

1
6 of 17
UCHIYAMA et Al.
|
5
7.6 μmol), PhCH=CHCH (1.20 mg, 10.2 μmol)/
[6] B. E. Maryanoff, A. B. Reitz, M. S. Mutter, R. R. Inners, H. R.
3
Ph C=CH (2.09 mg, 11.6 μmol) = 0.877/1.00, Yield
Almond Jr, R. R. Whittle, R. A. Olofson, J. Am. Chem. Soc. 1986,
2
2
1
08, 7664.
5
8%, (Z):(E) = 25:75.
[
7] H. J. Bestmann, W. Stransky, O. Vostrowsky, Chem. Ber. 1976,
09, 1694.
[8] T. Kawashima, K. Kato, R. Okazaki, J. Am. Chem. Soc. 1992,
1
4
.7
X-ray crystallographic analysis
|
1
14, 4008.
Single crystals of 3 and 11 were grown by the slow evapo-
ration at room temperature, respectively. A colorless block
crystal for each of 3 and 11 having approximate dimensions
[
9] K.-Y. Akiba, “Chemistry of Hypervalent Compounds”, Wiley-
VCH, New York, NY, 1999.
[10] E. Vedejs, T. J. Fleck, J. Am. Chem. Soc. 1989, 111, 5861.
3
[
[
[
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of 0.50 × 0.43 × 0.33 and 0.53 × 0.52 × 0.23 mm , respec-
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tively, was mounted on a glass fiber. All measurements were
carried out on a Bruker AXS Inc. SMART APEX II with
graphite monochromated Mo-Kα radiation (λ = 0.71073 Å).
The structure was solved by direct methods and expanded
using Fourier techniques. All non-hydrogen atoms were re-
fined anisotropically, while hydrogen atoms were refined iso-
tropically. Crystallographic data are summarized in Table 3.
Crystallographic data for 3 and 11 have been depos-
ited with Cambridge Crystallographic Data Centre: CCDC
13] J. C. Martin, E. F. Perozzi, Science 1976, 191, 154.
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[
[
[
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17] Y. Uchiyama, T. Ohtsuki, R. Murakami, M. Shibata, J. Sugimoto,
Eur. J. Org. Chem. 2017, 1, 159.
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Phosphorus Sulfur Silicon Relat. Elem. 2016, 191, 1523.
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Silicon Relat. Elem. 2015, 190, 633.
1
870406 and 1870407 for 3 and 11. These data can be ob-
tained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html (or from the Cambridge Crystallographic
Data Centre, 12, Union Road, Cambridge, CB2 1EZ, UK;
Fax: +44 1223 336033; or deposit@ccdc.cam.ac.uk).
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ACKNOWLEDGMENTS
22] Y. Uchiyama, S. Kuniya, R. Watanabe, T. Ohtsuki, Phosphorus
Sulfur Silicon Relat. Elem. 2018, [Epub ahead of print] https://
doi.org/10.1080/10426507.2018.154405
This study was partially supported by a Grant-in-Aid for
Encouragement of Young Scientists (B) to Y. U. (No.
[
23] Y. Uchiyama, S. Kuniya, R. Watanabe, T. Ohtsuki, Phosphorus
Sulfur Silicon Relat. Elem. 2018, [Epub ahead of print] https://
doi.org/10.1080/10426507.2018.154410
1
6750041 and No. 18750037) from the Ministry of Education,
Culture, Sports, Science, and Technology of Japan, the
Ogasawara Foundation for Oversea Visiting Researchers,
the Mikiya Foundation for Oversea Visiting Researchers,
the Murata Science Foundation, and Kitasato University
Research Grant for Young Researchers. The author, Y. U.,
thanks Emeritus Professor Takayuki Kawashima for useful
advice. The authors would like to thank Editage (www.edit-
age.jp) for English language editing.
[24] H. Tsuji, T. Inoue, Y. Kaneta, S. Sase, K. Tamao, Organomet
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006, 25, 6142.
[
25] Y. Uchiyama, J. Sugimoto, M. Shibata, G. Yamamoto, Y. Mazaki,
Bull. Chem. Soc. Jpn. 2009, 82, 819.
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26] Y. Uchiyama, G. Yamamoto, Chem. Lett. 2005, 34, 966.
27] J. Emsley, The Elements, 3rd ed., Oxford University Press Inc.,
New York, NY 1998, 22, 26, 36, 52, 86, 114, 152, 190, 214.
[
28] Gaussian 03, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E.
Scuseria, M. A. Robb, J. R. Cheeseman, J. A. Montgomery
Jr, T. Vreven, K. N. Kudin, J. C. Burant, J. M. Millam, S. S.
Iyengar, J. Tomasi, V. Barone, B. Mennucci, M. Cossi, G.
Scalmani, N. Rega, G. A. Petersson, H. Nakatsuji, M. Hada,
M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T.
Nakajima, Y. Honda, O. Kitao, H. Nakai, M. Klene, X. Li, J.
E. Knox, H. P. Hratchian, J. B. Cross, V. Bakken, C. Adamo,
J. Jaramillo, R. Gomperts, R. E. Stratmann, O. Yazyev, A. J.
Austin, R. Cammi, C. Pomelli, J. W. Ochterski, P. Y. Ayala,
K. Morokuma, G. A. Voth, P. Salvador, J. J. Dannenberg, V.
G. Zakrzewski, S. Dapprich, A. D. Daniels, M. C. Strain, O.
Farkas, D. K. Malick, A. D. Rabuck, K. Raghavachari, J. B.
Foresman, J. V. Ortiz, Q. Cui, A. G. Baboul, S. Clifford, J.
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C. Y. Peng, A. Nanayakkara, M. Challacombe, P. M. W. Gill,
ORCID
Yosuke Uchiyama
org/0000-0002-9513-1147
https://orcid.
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