Novel 2-Phosphabicyclo[2.2.2]oct-5-ene Derivatives and Their Use in Phosphinylations

Article abstract of DOI:10.1002/hc.10221

The [4 + 2] cycloaddition of the double-bond isomers (A and B) of dihydrophosphinine oxide 1 afforded novel phosphabicyclo[2.2.2]oct-5-ene derivates (2-4), formation of which was justified by PM3 semiempirical calculations. The compounds of dimer type (2-

Full text of DOI:10.1002/hc.10221

Heteroatom Chemistry
Volume 15, Number 2, 2004
Novel 2-Phosphabicyclo[2.2.2]oct-5-ene
Derivatives and Their Use in Phosphinylations
Gyo¨rgy Keglevich,1 Ja´nos Kova´cs,1 Tama´ s Ko¨rtve´lyesi,2 Gyula
Parlagh,3 T´ımea Imre,4 Krisztina Luda´nyi,4 La´szlo´ Hegedu´´s,1 Miklo´s
Hanusz,5 Ka´lma´n Simon,5 Andrea Ma´rton,1 Gyo¨rgy Marosi,1 and
La´szlo´ To´´ke6
1Department of Organic Chemical Technology, Budapest University of Technology and Economics,
1521 Budapest, Hungary
2Department of Physical Chemistry, University of Szeged, 6701 Szeged, Hungary
3Department of Physical Chemistry, Budapest University of Technology and Economics, 1521
Budapest, Hungary
4Hungarian Academy of Sciences, Chemical Research Center, 1525 Budapest, Hungary
5Chinoin Company Ltd. (member of Sanofi-Synthelabo Group), 1045 Budapest, Hungary
6Research Group of the Hungarian Academy of Sciences at the Department of Organic Chemical
Technology, Budapest University of Technology and Economics, 1521 Budapest, Hungary
Received 28 August 2003
(7) were also synthesized and tested in fragmenta-
ABSTRACT: The [4 + 2] cycloaddition of the double-
ꢀ
C
tion.
2004 Wiley Periodicals, Inc. Heteroatom Chem
bond isomers (A and B) of dihydrophosphinine ox-
ide 1 afforded novel phosphabicyclo[2.2.2]oct-5-ene
derivates (2–4), formation of which was justified
by PM3 semiempirical calculations. The compounds
of dimer type (2–4) were utilized in the UV light-
mediated fragmentation-related phosphinylation of
nucleophiles, especially in that of alcohols. To explore
the role of structural modifications on the fragmenta-
tion ability, disulfide 5, phosphabicyclooctane 7 ob-
tained by the hydrogenation of 2, and the adduct
of dihydrophosphinine oxide 1 with benzoquinone
15:97–106, 2004; Published online in Wiley InterScience
(www.interscience.wiley.com). DOI 10.1002/hc.10221
INTRODUCTION
The phosphorylation of O- and N-nucleophiles by
low-coordinated P-fragments, like methylenephos-
phine oxides, is a novel synthetic method [1].
Because of their strained framework, the phos-
phabicyclo[2.2.2]octenes and -octadienes are excel-
lent precursors of methylenephosphine oxides, and
hence they can be used in the fragmentation re-
lated phosphorylation of a variety of nucleophiles
[2–7]. The photolysis of phosphabicyclo[2.2.2]octene
derivatives in the presence of alcohols or amines
led to phosphonic and phosphinic esters/amides
[3–5]. The potential of this method is that the
´
The article is dedicated to Professor Dr. SANDOR ANTUS
(University of Debrecen, Hungary) on the occasion of his sixti-
eth birthday.
Correspondence to: Gyo¨rgy Keglevich; e-mail: keglevich
@oct.bme.hu.
Contract grant sponsor: OTKA.
Contract grant numbers: T 042479 and D 034586.
2004 Wiley Periodicals, Inc.
c
ꢀ
97

98 Keglevich et al.
phosphonic and the phosphinic derivatives are ob-
tained selectively and under mild conditions. The
phosphabicyclooctadienes were also efficient in
the thermo-induced phosphorylation of phenol
derivates [7].
As regards the mechanism of the fragmentation-
related phosphorylations, the thermolyses involve
methylenephosphine oxides as the intermediates
[2,7], at the same time, the photolyses rather follow
an addition–elimination route with a pentavalent-
pentacoordinated P-intermediate [2–4,8,9]. Re-
cently, new types of phosphabicyclooctenes with
sterically demanding substituent on the phosphorus
atom [9,10], as well as derivatives incorporating
nitrogen atoms in the framework [9], have been
described.
oxides may enter into Diels-Alder cycloaddition with
each other at 110◦C [11]. As can be seen on the ex-
ample of the P-phenyl substituted model compound,
isomer 1B served as the diene component, while
1A acted as the dienophile to afford phosphabicy-
clooctene 2 which can be regarded to be a dimer of
two units of dihydrophosphinine oxide 1 (Scheme 1).
Dimer 2 was isolated in 34% yield after chro-
matography and its stereostructure was confirmed
by single crystal X-ray analysis showing that the two
six-membered P-cycles are joined in the endo ring
fusion (Fig. 1).
In the phosphabicyclo[2.2.2]oct-5-ene moiety of
molecule 2, all the three rings have a boat conforma-
tion with C(1) and C(4) on the same side of the plain,
determined by the remaining four atoms. The annel-
lating tetrahydrophosphinine ring has a screw boat
conformation with P(9) above and C(10) below the
plain laid through the C(7), C(8), C(11), and C(12)
atoms. The phenyl group attached to P(9) is in ax-
ial position. At the same time, the P(2)-phenyl sub-
stituent is in an equatorial position toward the C(1),
P(2), C(3), C(4), C(8), C(7) ring, while in an axial po-
sition toward the C(1), P(2), C(3), C(4), C(5), C(6)
ring. Endocyclic torsion angles summarized in Fig. 1
define the conformation of the molecule (2). The
In this paper, a novel dimerization reaction
affording phosphabicyclo[2.2.2]octenes with a six-
membered ring fusion in positions 7 and 8 is pre-
sented and the fragmentation properties of the cy-
cloadducts related are discussed.
RESULTS AND DISCUSSION
We have recently observed that the double-bond
isomers of methyl-4-chloro-1,2-dihydrophosphinine
SCHEME 1

Novel 2-Phosphabicyclo[2.2.2]oct-5-ene Derivatives and Their Use in Phosphinylations 99
◦
◦
˚
FIGURE 1 Perspective view of 2 with bond lengths (A), bond angles ( ), and torsion angles ( ) obtained by X-ray. The ge-
ometrical data calculated by the PM3 method are shown in parentheses. C(1) P(2) 1.822(3) [1.899], P(2) C(3) 1.815(4)
[1.854], C(3) C(4) 1.555(5) [1.532], C(4) C(5) 1.509(4) [1.505], C(5) C(6) 1.328(4) [1.348], C(6) C(1) 1.517(5) [1.487],
C(1) C(7) 1.566(4) [1.542], C(7) C(8) 1.557(4) [1.539], C(8) C(4) 1.547(4) [1.541], C(8) P(9) 1.817(3) [1.888], P(9) C(10)
1.797(3) [1.833], C(10) C(11) 1.515(5) [1.480], C(11) C(12) 1.329(5) [1.344], C(12) C(7) 1.505(5) [1.502]. C(1) P(2) C(3)
98.20(16) [97.07], C(1) P(2) C(13) 106.67(16) [107.27], C(1) P(2) O(2) 113.20(16) [114.24], O(2) P(2) C(3) 115.80(18)
[115.52], O(2) P(2) C(13) 112.81(17) [113.71], C(13) P(2) C(3) 108.84(18) [107.51], C(8) P(9) C(10) 102.90(16)
[101.12], C(8) P(9) O(1) 113.20(15) [114.69], C(8) P(9) C(19) 106.94(16) [103.33], C(10) P(9) C(19) 103.96(17)
[108.77], O(1) P(9) C(19) 113.95(16) [113.32], O(1) P(9) C(10) 114.80(16) [114.40]. C(6) C(1) P(2) C(3) −62.2(2)
[−51.4], C(7) C(1) P(2) C(3) 57.6(2) [65.8], C(1) P(2) C(3) C(4) 6.5(3) [−7.4], P(2) C(3) C(4) C(5) 50.0(3) [62.9],
P(2) C(3) C(4) C(8) −68.5(3) [−57.4], C(8) C(4) C(5) C(6) 52.9(4) [52.0], C(3) C(4) C(5) C(6) −65.2(4) [−67.8],
C(4) C(5) C(6) C(1) 2.7(4) [−0.94], C(7) C(1) C(6) C(5) −55.8(4) [−54.1], P(2) C(1) C(6) C(5) 62.1(3) [61.0],
C(6) C(1) C(7) C(8) 50.2(3) [57.0], P(2) C(1) C(7) C(8) −66.8(3) [−60.3], C(5) C(4) C(8) C(7) −52.6(3) [−44.5],
C(3) C(4) C(8) C(7) 66.3(3) [74.0], C(5) C(4) C(8) P(9) 75.6(3) [88.5], C(1) C(7) C(8) C(4) 4.0(3) [−7.0].
1
tetrahedron around P(2) is somewhat distorted. The
two most extreme values are C(1) P(2) C(3) 98.2(2)◦
and O(2) P(2) C(3) 115.8(2)◦. A smaller distorsion
can be seen around the P(9) atom. The two most ex-
treme values are 104.0(2)◦ for C(10) P(9) C(19) and
114.8(2)◦ for C(10) P(9) O(1).
A careful refinement of the crude reaction mix-
ture by chromatography led to two minor compo-
nents that are new kinds of dimers (3 and 4) of dihy-
drophosphinine oxide 1 (Scheme 1).
Dimer 3 was derived by the Diels-Alder reac-
tion of dihydrophosphinine oxides 1B with 1A, while
product 4 by the [4 + 2] cycloaddition of two units
of 1A. Contrary to the case of dimer 2, where the two
phosphorus atoms are separated by four bonds, the
two heteroatoms in phosphabicyclooctenes 3 and 4
are coupled (3 JPP = 38.3 and 41.7 Hz, respectively).
The structure of all the products (2–4) was confirmed
by 13C NMR. The olefinic proton of compound 4 ap-
peared at δH 6.4 in the H NMR spectrum. The ele-
mental composition of the dimers 2–4 was confirmed
by HR-MS.
Assuming an endo fusion of the rings, as
suggested by analogies [3] and disregarding the
configuration of the phosphorus atoms, the combi-
nation of the double-bond isomers (A and B) of dihy-
drophosphinine oxide 1 may lead to eight structures
(Fig. 2), from which the formation of two species (2
and 3) seems to be more favourable due to the lack
of steric compression caused by the skeletal methyl
group(s). As a matter of fact, products 2 and 3 were
among those isolated from the reaction mixture. To
evaluate the relative stability of the products, the
values of heat of formation (ꢀH◦) were calculated
f
for the eight possible isomers (Fig. 2) by the PM3
method [12] that is well suited to computation of
phosphorus-containing systems [13,14]. The quan-
tum chemical calculations justified the preference

100 Keglevich et al.
FIGURE 2 Possible products from the interaction of two units of dihydrophosphinine oxide 1A/1B.
for the formation of isomers 2 and 3 with ꢀH◦f val-
ues of −24.09 and −22.84 kcal/mol, respectively (col-
umn 5 of Table 1). For the third species isolated (4),
an enthalpy of −13.73 kcal/mol was obtained which
was comparable with the corresponding values of
isomers (1A + 1A)2, (1B + 1B)1, and (1B + 1B)2
(−12.34, −17.44, and −14.53 kcal/mol, respectively).
The perspective view of products 3 and 4 is shown
in Figs. 3 and 4, respectively. (1A + 1B)1 and (1A +
1B)2 having methyl groups in and around the junc-
tion were the most unfavourable species in the se-
ries as suggested by the ꢀH◦f values of −7.60 and
−1.14 kcal/mol, respectively. It is noted that each
of the eight ꢀH◦f values is the average of those ob-
tained for the corresponding four P-configurational
isomers (columns 1–4 of Table 1). The difference
between the extreme values of the members within
the series fell in the range of 0.50–2.65 kcal/mol (col-
umn 6 of Table 1). The geometrical data obtained for
product 2 by the PM3 method were in acceptable

Novel 2-Phosphabicyclo[2.2.2]oct-5-ene Derivatives and Their Use in Phosphinylations 101
TABLE 1 Heat of Formation (ꢀH◦f ) in kcal/mol for the Possible Cycloadducts Calculated by the PM3 Semiempirical Method
Average for
the Four
Diastereomers
Difference
of the Two
Extreme Values
Diastereomers
Products
P
O P
O
P
O O
P
O
P P
O
O
P O
P
(1A + 1A)1 = 4
(1B + 1A)1 = 3
(1A + 1B)1
−13.03
−22.19
−5.79
−14.62
−23.77
−8.44
−13.70
−22.64
−7.60
−13.58
−22.77
−8.28
−13.73
−22.84
−7.53
1.59
1.58
2.65
2.33
2.59
0.94
1.55
0.50
(1B + 1B)1
−15.85
−10.83
−23.89
−0.59
−18.18
−12.91
−23.68
−1.77
−17.66
−12.18
−24.16
−0.32
−18.08
−13.42
−24.62
−1.87
−17.44
−12.34
−24.09
−1.14
(1A + 1A)2
(1B + 1A)2 = 2a
(1A + 1B)2
(1B + 1B)2
−14.79
−14.42
−14.62
−14.29
−14.53
aThe ꢀH◦f values for the diastereomers obtained by the MNDO-d method are −94.60, −94.29, −94.94, and −94.68, respectively.
agreement with those calculated from the X-ray
structure (Fig. 1). This means that the PM3 calcu-
lations indeed describe the pentavalent organophos-
phorus compounds adequately.
sulfide) (5) by a standard procedure [15] in a yield of
68% after chromatography (Scheme 2).
1
Product 5 was characterized by 31P, 13C, and H
NMR, as well as mass spectroscopical data. As a
To see how the structural modification affects
the fragmentation properties, bis(phosphine oxide)
2 was converted to the corresponding bis(phosphine
˚
˚
FIGURE 3 Perspective view of 3 with bond lengths (A),
FIGURE 4 Perspective view of 4 with bond lengths (A),
bond angles (◦), and torsion angles (◦) calculated by the
PM3 method. C(1) P(2) 1.896, P(2) C(3) 1.859, C(3) C(4)
1.527, C(4) C(5) 1.501, C(5) C(6) 1.348, C(6) C(1)
1.490, C(1) C(7) 1.524, C(7) C(8) 1.545, C(8) C(4) 1.556,
C(8) C(9) 1.501, C(9) C(10) 1.349, C(10) C(11) 1.476,
C(11) P(12) 1.838, P(12) C(7) 1.893. C(1) P(2) C(3)
96.13, C(1) P(2) C(13) 107.25, C(1) P(2) O(2) 114.81,
bond angles (◦) and torsion angles (◦) calculated by the
PM3 method. C(1) P(2) 1.886, P(2) C(3) 1.866, C(3) C(4)
1.544, C(4) C(5) 1.508, C(5) C(6) 1.346, C(6) C(1)
1.482, C(1) C(7) 1.524, C(7) C(8) 1.545, C(8) C(4) 1.569,
C(8) C(9) 1.506, C(9) C(10) 1.352, C(10) C(11) 1.475,
C(11) P(12) 1.846, P(12) C(7) 1.897. C(1) P(2) C(3)
94.49, C(1) P(2) C(13) 108.32, C(1) P(2) O(2) 115.84,
O(2) P(2) C(3)
115.27,
O(2) P(2) C(13)
113.93,
O(2) P(2) C(3)
114.91,
O(2) P(2) C(13)
113.69,
C(13) P(2) C(3) 107.79, C(11) P(12) C(7) 99.95,
C(11) P(12) O(1) 116.35, C(11) P(12) C(19) 102.56,
C(7) P(12) C(19) 105.23, O(1) P(12) C(19) 113.68,
O(1) P(12) C(7) 117.09. C(6) C(1) P(2) C(3) −57.9,
C(7) C(1) P(2) C(3) 61.2, C(1) P(2) C(3) C(4) 2.3,
P(2) C(3) C(4) C(5) 54.9, P(2) C(3) C(4) C(8) −63.7,
C(8) C(4) C(5) C(6) 53.5, C(3) C(4) C(5) C(6) −67.2,
C(4) C(5) C(6) C(1) 1.9, C(7) C(1) C(6) C(5) −51.6,
P(2) C(1) C(6) C(5) 61.4, C(6) C(1) C(7) C(8) 41.3,
C(13) P(2) C(3) 107.79, C(11) P(12) C(7) 99.11,
C(11) P(12) O(1) 116.64, C(11) P(12) C(19) 102.50,
C(7) P(12) C(19) 105.88, O(1) P(12) C(19) 113.88,
O(1) P(12) C(7) 116.80. C(6) C(1) P(2) C(3) −61.9,
C(7) C(1) P(2) C(3) 57.2, C(1) P(2) C(3) C(4) 8.9,
P(2) C(3) C(4) C(5) 43.7, P(2) C(3) C(4) C(8) −65.2,
C(8) C(4) C(5) C(6) 52.7, C(3) C(4) C(5) C(6) −65.2,
C(4) C(5) C(6) C(1) 3.6, C(7) C(1) C(6) C(5) −47.7,
P(2) C(1) C(6) C(5) 63.0, C(6) C(1) C(7) C(8) 28.6,
P(2) C(1) C(7) C(8)
−58.5, C(3) C(4) C(8) C(7) 61.2, C(6) C(1) C(7) P(9)
−73.6,
C(5) C(4) C(8) C(7)
P(2) C(1) C(7) C(8)
−66.6, C(3) C(4) C(8) C(7) 49.3, C(6) C(1) C(7) P(9)
−83.3,
C(5) C(4) C(8) C(7)
−92.3, C(1) C(7) C(8) C(4) 12.5.
−104.3, C(1) C(7) C(8) C(4) 26.4.

102 Keglevich et al.
SCHEME 2
further modification, we wished to prepare the fully
saturated phosphabicyclooctane (7, Ar1 = Ar2 = Ph).
The reduction could not be led to give the desired
product (7, Ar1 = Ar2 = Ph) as the major component.
At 90◦C and 16 bar using a 10% palladium on car-
bon catalyst, a complex mixture containing species
6 and 7 with phenyl or cyclohexyl substituent(s) on
the phosphorus atom(s) (6, Ar1 = Ar2 = Ph, (M + H)+
= 411, 51%; 7, Ar1 = Ar2 = Ph, (M + H)+ = 413, 18%;
6, Ar1 = Ph or C6H11, Ar2 = C6H11 or Ph, (M + H)+ =
417, 16%; 7, Ar1 = Ph or C6H11, Ar2 = C6H11 or Ph,
(M + H)+ = 419, 12%; 6, Ar1 = Ar2 = C6H11, (M + H)+
= 423, 3%) was obtained as suggested by the mass
spectrum of the crude mixture (Scheme 2).
phabicyclooctane 9 as the mixture of four isomers
(the configurational isomers of double-bond isomers
9A and 9B) (Scheme 3).
Repeated column chromatography led to the
mixture of the two isomers of 9B that were char-
1
acterized by 31P, 13C, and H NMR, as well as mass
spectroscopical data.
The investigation of cycloadducts 2, 5, and 9
by TG and DTG suggested no significant difference
between their thermostability. The minimum of the
DTG curves was around 315◦C in all cases. At the
same time, the saturated derivative (8) revealed an
increased thermostability with a 415◦C minimum
of the DTG curve. This clearly shows the impact of
the unsaturation on the fragmentation ability of the
precursor.
The bridged P-heterocycles (2–5, 9) synthesized
were tested in fragmentation-related phosphinyla-
tions. The acetonitrile solution of dimer 2 was
irradiated at 254 nm in the presence of simple
Forcing the hydrogenation at 90◦C and 50 bar
for 30 h, all unsaturations in 2 were completely
saturated resulting in the formation of dicyclohexyl
phosphabicyclooctane derivative 8 obtained as a
single diastereomer in a yield of 27% after chro-
matography. It can be concluded that although the
selective hydrogenation of compound 2 cannot be
accomplished due to the presence of the six vulnera-
ble moieties, a complete reduction is possible under
appropriate conditions.
In the above examples (2–8), a tetrahydrophos-
phinine oxide ring was annellated to the usual phos-
phabicyclooctene (or -octane) skeleton in positions
7 and 8. To see a simpler case, we wished to synthe-
size a precursor annellated with cyclohexene ring.
For this, a 3:1 mixture of dihydrophosphinine ox-
ides 1A and 1B was reacted with benzoquinone
in boiling toluene. The cycloaddition yielded phos-
SCHEME 3

Novel 2-Phosphabicyclo[2.2.2]oct-5-ene Derivatives and Their Use in Phosphinylations 103
alcohols such as methanol, ethanol, propanol, and
isopropanol for 1 h. The phosphinic esters (11a–d),
which on the basis of δP shifts and HR-MS proved
to be identical with authentic samples [3], were ob-
tained in 71–89% yields after flash column chro-
matography (Scheme 4, Table 2).
Dimers 3 and 4 could be used in fragmentation-
related phosphinylation similarly to analogue 2. The
phosphinylation of methanol took place in an effi-
ciency of ca. 80% in both cases.
SCHEME 5
The isomeric mixture (A and B) of product 9 was
also an efficient precursor in the phosphinylation of
simple alcohols (Scheme 4, Table 1). Dimer 2 was not
so efficient in the UV light-mediated phosphinylation
of isopropylamine, as it was in that of alcohols. Iso-
propylamine was phosphinylated in 54% yield after
the work-up (Scheme 5, Table 1).
The photolysis utilizing the P-sulfide precursor
(5) in the presence of methanol led to thiophosphi-
nate 15 (Scheme 6, Table 1).
well as a disulfide derivative and the [4 + 2] cy-
cloadduct of the dihydrophosphinine oxide with ben-
zoquinone were suitable precursors in UV light-
mediated fragmentation-related phosphinylations.
However, the fully saturated phosphabicyclooctane
resisted the photoinduced transformation. None
of the phosphabicyclooctenes underwent thermo-
induced ejection of the bridging P-moiety suggest-
ing that only the strained bicyclooctadienes may be
useful in thermolyses.
Phosphabicyclooctane 8 did not undergo a
photo-induced reaction with methanol to furnish
phosphinate 11a indicating the dramatic effect of the
lack of a significant ring strain. On the other hand, no
stable molecule can be formed from 8 after the loss of
the bridging P-moiety. Moreover, there is also a pos-
sibility that in the lack of an obvious chromophore,
the UV light is not even absorbed by 8.
Neither dimer 2, nor cycloadduct 9 could be
utilized in the thermo-induced phosphinylation of
hydroquinone at 240◦C. This seems to be in agree-
ment with earlier experiences of ours [17] and with
the thermostability of the cycloadducts (2 and 9)
discussed above. The ring strain of the phosphabi-
cyclooctenes is indeed not enough to stimulate a
thermo-induced fragmentation [2].
EXPERIMENTAL
General
The 31P, 13C, and 1H NMR spectra were performed on
a Bruker DRX-500 spectrometer operating at 202.4,
125.7, and 500 MHz, respectively. Chemical shifts
are downfield relative to 85% H3PO4 or TMS. The
couplings are given in Hz. EI and/or FAB mass spec-
trometry was performed on a ZAB-2SEQ instrument.
Photolyses were conducted in a photochemical reac-
tor with a high pressure mercury lamp (125 W). The
starting dihydrophosphinine oxide 1 was prepared
as described earlier [18].
In summary, phosphabicyclo[2.2.2]octenes of
new type were introduced by the dimerization of
1-phenyl-dihydrophosphinine oxides. PM3 calcula-
tions justified the formation of the three isomers
isolated from the reaction mixture. A study on
the fine tuning of the structure and reactivity of
phosphabicyclooctane derivatives annellated with
a six-membered ring showed that the dimers as
6,11-Dichloro-5,12-dimethyl-3,5-diphenyl-3,9-
diphosphatricyclo[6.2.2.02,7]dodeca-5,11-diene-
3,9-dioxide (2) [19]
A toluene solution (10 ml) containing 3.9 g (16.2
mmol) of dihydrophosphinine oxide (1) consisting
SCHEME 4
SCHEME 6

104 Keglevich et al.
TABLE 2 Phosphinic Derivates (11a–d, 13, and 15) Prepared by the Photolysis of Cycloadducts 2, 9, and 5 in the Presence
of Nucleophiles
Nucleophile
Product
Yield (%)
δP (CDCl3)
δP [Ref.]
(M + H)+
2
2
2
2
9
9
9
2
5
MeOH
EtOH
nPrOH
i PrOH
MeOH
EtOH
nPrOH
i PrNH2
MeOH
11a
11b
11ca
11db
11a
11b
11c
13c
89
84
79
71
78
73
53
54
51
45.2
43.2
42.9
41.2
45.1
43.7
42.9
31.4
91.5
44.8 [3], 45.0 [16]
42.7 [3]
42.8 [3]
41.3 [3]
44.8 [3], 45.0 [16]
42.7 [3]
171
185
199
199
171
185
199
198
187
42.8 [3]
29.8 [4]
15
am/z (rel. int.) 198 (M+, 2), 183 (M–Me, 2), 139 (M–OPr, 100).
bm/z (rel. int.) 198 (M+, 3.6), 183 (M–Me, 12.7), 139 (M–Oi Pr, 100).
cm/z (rel. int.) 197 (M+, 1), 182 (M–Me, 83), 139 (M–NHi Pr, 100).
e
ꢁꢁ
ꢁ
ꢁꢁ
of 70% of A and 30% of B isomer was stirred at boil-
ing point for 7 days. The solvent was evaporated, and
the residue purified by repeated column chromatog-
raphy (silica gel, 3% methanol in chloroform) to give
0.66 g (34% based on 1B) of dimer 2 as colorless
crystals; mp 298–301◦C (acetone); 31P NMR (CDCl3) δ
37.5 (P2), 28.6 (P9); 13C NMR (CDCl3) δ 19.6 (C6–Me),
24.6 (Jꢁꢁ = 7.4, C11–Me), 31.0 (Jꢁꢁ = 63.4, C10), 32.0
131.0 (J = 11.0, C3 ), 132.3 (J = 100.5, C1 ), C1 over-
ꢁ
ꢁꢁ
ꢁ
ꢁꢁ
lapped, 132.4 (C4 , C4 ), J : coupled by P2, J : coupled
by P12, a–emay be reversed; IR (film) 1170, 1198, 1436,
1650, 2937 cm−1; M+found = 476.0537, C24H24Cl2O2P2
requires 476.0629 for the 35Cl isotopes.
6,12-Dichloro-5,8-dimethyl-3,10-diphenyl-3,10-
diphosphatricyclo[6.2.2.02,7]dodeca-5,11-diene-
3,10-dioxide (4) [19]
(Jꢁ = 76.0, Jꢁꢁ = 10.9, C3), 39.7 (J = 5.9, C7 ), 40.0
a
a
(Jꢁ = 67.2, Jꢁꢁ = 13.5, C1), 45.1 (C4 ), 47.7 (Jꢁꢁ = 63.6,
b
C8), 127.6 (C6 ), 127.7 (C11b), 129.0, (J = 12.0, C2 c),
31P NMR (CDCl3) δ 36.0 and 38.7 JPP = 41.7; 13C
3
ꢁ
129.1 (J = 11.9, C2 c), 129.3 (J = 12.1, C12d), 130.1
NMR (CDCl3) δ 20.5 (Jꢁ = 11.3, C4–Me), 24.8 (Jꢁꢁ =
9.9, C10–Me), 34.7 (Jꢁꢁ = 59.3, C11a), 40.9 (Jꢁ = 73.8,
ꢁꢁ
d
(J = 9.6, C3 e), 130.2 (J = 10.0, C5 ), 131.3 (J = 11.8,
ꢁ
C3 ), 131.5 (J = 95.9, C1 ), 132.1 (J = 100.9, C1 f),
e
f
a
b
b
ꢁꢁ
ꢁ
ꢁꢁ
C3 ), 34.6 (J = 67.3, C7 ), 38.6 (J = 61.0, C1 ), 46.9
(J = 5.6, C4), 56.4 (Jꢁ = 13.1, Jꢁꢁ = 4.7, C8), 126.7
ꢁ
ꢁꢁ
ꢁ
ꢁꢁ
132.6 (C4 , C4 ), J : coupled by P2, J : coupled by
P9, a–fmay be reversed; H NMR (CDCl3) δ 1.58 (s,
1
(C10), 126.8 (J = 3.9, C6), 128.6 (J = 11.0, C2
c),
ꢁ
128.8 (J = 11.0, C2 c), 130.5 (J = 8.1, C3 d), 130.9
3H, Me), 1.85 (s, 3H, Me), 7.46–7.76 (m, 5H, Ar);
IR (KBr disc) 1168, 1196, 1436, 1650, 2935 cm−1;
MS, m/z (rel. int.) 476 (M+, 20), 441 (M-35, 19), 337
(M–PhPO-15, 55), 125 (PhPO + H, 100), 77 (Ph, 72);
M+found = 476.0527, C24H24Cl2O2P2 requires 476.0629
for the 35Cl isotopes.
Further chromatography of the additional frac-
tions combined led to 0.12 g (7%) of dimer 3 and to
0.07 g (2%) of product 4, both as thick oils, listed and
characterized below.
ꢁꢁ
ꢁ
d
e
e
ꢁ
ꢁꢁ
ꢁ
ꢁꢁ
(J = 8.7, C3 ), 132.1 (C4 ) , 132.4 (C4 ) , 141.9 (J =
10.2, C5), Jꢁ: coupled by P2, Jꢁꢁ: coupled by P12,
a–emay be reversed; H NMR (CDCl3) δ1.66 (s, 3H,
1
Me), 1.85 (s, 3H, Me), 6.44 (d, 1H, CH ); IR
(film) 1171, 1200, 1437, 1649, 2937 cm−1; Mf+ound
=
476.0530, C24H24Cl2O2P2 requires 476.0629 for the
35Cl isotopes.
6,11-Dichloro-5,12-dimethyl-3,5-diphenyl-3,9-
diphosphatricyclo[6.2.2.02,7]dodeca-5,11-diene-
3,9-disulfide (5) [19]
6,12-Dichloro-5,11-dimethyl-3,10-diphenyl-3,10-
diphosphatricyclo[6.2.2.02,7]dodeca-5,11-diene-
3,10-dioxide (3) [19]
To a degassed solution of 0.17 g (0.36 mmol) of dimer
2 in 8 ml of benzene was added 0.2 g (0.90 mmol) of
phosphorus pentasulfide and the mixture was stirred
at the boiling point, under nitrogen for 20 h. Sol-
vent was evaporated and the residue so obtained was
purified by column chromatography (silica gel, 3%
methanol in chloroform) to afford 0.12 g (68%) of
disulfide 5 as a thick oil. 31P NMR (CDCl3) δ 41.9 (P2)
3
31P NMR (CDCl3) δ 31.1 and 40.0 JPP = 38.3; 13C
NMR (CDCl3) δ 18.7 (C6–Me), 24.6 (Jꢁꢁ = 7.4, C11–
a
Me), 28.1 (J = 75.4, C11a), 32.4 (J = 62.7, C3 ), 32.6
(Jꢁꢁ = 62.7, C7), 42.2 (Jꢁ = 61.5, C1), 45.6 (J = 6.8,
C4), 51.4 (J = 7.7, C8), 127.0 (C6),b 127.1 (C10),b 128.7
(J = 11.6, C2 c), 128.8 (J = 11.2, C2 c), 130.0 (J = 8.6,
ꢁ
ꢁꢁ
C3 e), 130.4 (J = 14.9, C5 ), 130.5 (J = 17.9, C9 ),
and 38.8 JPP = 2.9; 13C NMR (CDCl3) δ 19.7 (Jꢁ =
d
d
3
ꢁ

Novel 2-Phosphabicyclo[2.2.2]oct-5-ene Derivatives and Their Use in Phosphinylations 105
2.2, C6–Me), 24.2 (Jꢁꢁ = 7.5, C11–Me), 35.4 (Jꢁꢁ = 48.7,
9B-1: 31P NMR (CDCl3) δ 40.9; 13C NMR
(CDCl3) δ 20.1 (J = 13.0, C6–Me), 31.7 (J = 75.7,
C3), 39.4 (J = 67.2, C1), 39.9 (J = 6.4, C8), 45.2 (C7),
47.3 (C4), 115.5 (C10)a, 116.6 (C11)a, 127.8 (J = 5.5,
C10), 38.3 (Jꢁ = 60.7, Jꢁꢁ = 12.4, C3), 40.5 (Jꢁ = 49.7,
a
a
Jꢁꢁ = 11.3, C1), 41.4 (J = 7.5, C7 ), 45.7 (J = 4.6, C4 ),
50.1 (Jꢁꢁ = 46.4, C8), 128.9 (C6),b 129.0 (C11),b 128.5
(J = 12.1, C2 c), 128.8 (J = 12.1, C2 c), 133.1 (J = 8.1,
ꢁ
ꢁ
b
b
ꢁ
ꢁꢁ
C6), 129.6 (J = 11.9, C2 ) , 130.2 (J = 9.0, C3 ) , 133.3
C12d), 125.4 (J = 9.7, C3 e), 127.7 (J = 8.4, C5 ), 131.2
ꢁ
d
c
c
(C4 ), 146.0 (C9) , 150.9 (C12) , a–cmay be reversed; 1H
NMR (CDCl3) δ 1.82 (s, 3H, C6–Me), 6.67–6.89 (m,
2H, CH ), 7.45–7.74 (m, 5H, Ar).
ꢁ
e
f
ꢁꢁ
ꢁ
(J = 9.7, C3 ), 130.2 (J = 78.0, C1 ), 132.1 (J = 83.6,
f
ꢁ
ꢁꢁ
ꢁꢁ
ꢁ
ꢁꢁ
C1 ), 131.6 (C4 ), 131.9 (C4 ), J : coupled by P2, J :
coupled by P9, a–fmay be reversed; H NMR (CDCl3)
1
9B-2: 31P NMR (CDCl3) δ 32.4; 13C NMR (CDCl3)
δ 20.1 (J = 13.0, C6–Me), 31.6 (J = 76.2, C3) 39.3
(J = 67.6, C1), 39.9 (J = 6.4, C8), 45.2 (C7), 47.8
δ 1.48 (s, 3H, Me), 1.81 (s, 3H, Me) 7.43–7.84 (m, 5H,
Ar); (M+H)+ = 509; Mf+ound = 508.0111 C24H24Cl2S2P2
requires 508.0172 for the 35Cl isotopes.
a
a
b
ꢁ
(C4), 117.0 (C10), 117.6 (C11), 129.5 (J = 11.5, C2 ),
b
c
ꢁ
ꢁ
131.4 (J = 8.9, C3 ), 133.1 (C4 ), 150.3 (C9), 150.9
(C12),c; a–cmay be reversed; 1H NMR (CDCl3) δ 1.56 (s,
3H, C6–Me), 6.67–6.89 (m, 2H, CH ), 7.45–7.74 (m,
5H, Ar).
5,12-Dimethyl-3,5-dicyclohexyl-3,9-
diphosphatricyclo[6.2.2.02,7]dodeca-3,9-
dioxide (8) [19]
General Procedure for the Synthesis
of Methyl-Phenylphosphinates 11a–d
Dimer 2 (0.30 g; 0.63 mmol) was hydrogenated in 30
ml of methanol in the presence of 0.3 g Pd/C at 90◦C
and 16 bar for 5 h in an autoclave, the pressure was
then gradually increased to 50 bar, and the reduction
was continued at 90◦C for 30 h. The mixture was
filtered and the filtrate evaporated to leave a crude
product that was purified by column chromatogra-
phy as above to give 0.07 g (27%) of product 8 as an
oil and as a single isomer. 31P NMR (CDCl3) δ 52.5 (P2)
and 46.1; 13C NMR (CDCl3) δ 22.8 (J = 15.7, C4)a, 24.5
(C6–Me)b, 25.3 (J = 6.1, C11–Me)b, 25.9 (C12)c, 28.3
(C6)d, 28.9 (J = 1.5, C11)d, 30.0 (C5)c, 30.1 (Jꢁꢁ = 59.0,
C10), 31.7 (C7)a, 32.5 (Jꢁꢁ = 12.0, Jꢁ = 52.7, C3), 34.1
(Jꢁ = 66.7, C1), 40.0 (Jꢁꢁ = 66.5, C8); a–dmay be re-
versed, Jꢁ: coupled by P2, Jꢁꢁ: coupled by P9; 1H NMR
(CDCl3) δ1.14(J = 6.1, Me), 1.25 (J = 7.1, Me); IR
(film) 1152, 1449, 2928 cm−1; (M+H)f+ound = 424.2595,
C24H42O2P2 requires 424.2660.
The solution of 0.10 g (0.21 mmol) of dimer 2 or
0.10 g (0.29 mmol) of cycloadduct 9 in 40 ml of ace-
tonitrile and 4 ml of the corresponding alcohol was
irradiated in a photochemical quartz reactor with a
125 W mercury lamp for 1 h. Volatile components
were removed and the residue so obtained was pu-
rified by flash column chromatography (silica gel,
3% methanol in chloroform) to give the correspond-
ing phosphinates (11a–d) as oils. The experimental
details are listed in Table 2. The use of 4 ml of iso-
propylamine instead of an alcohol led to phosphinic
amide 13.
Disulfide 5 (0.10 g; 0.20 mmol) could replace
dioxide 2, but the air had to be removed by nitro-
gen prior to the irradiation.
1- and 12-Methyl 11-chloro-9-phenyl-9ꢀ5-
phosphatricyclo[6.2.2.02,7]dodeca-4,11-diene-
3,6-dione 9-oxide (9) [19]
Crystal Data for Phosphabicyclooctene 2
X-ray diffraction data of single crystal of 2 were
collected at 293 K; Crystal data for 2: C24H24O2P2Cl2,
M = 477.31, colorless, needle shape crystal, ap-
proximate dimensions 0.20 × 0.10 × 0.50 mm,
A 15 ml toluene solution containing 0.80 g (3.35
mmol) of dihydrophosphinine oxide 1 [16] consist-
ing of 75% of the A and 25 % of the B isomer and 0.50
g (4.63 mmol) of benzoquinone was stirred at boiling
point for 4 days. The solvent was evaporated, and the
residual material purified by flash chromatography
as above to furnish 0.42 g (36%) of product 8 consist-
ing of four isomers (δP 32.0 (34%), 38.1 (17%), 38.2
(15%), and 40.5 (34%)). Repeated chromatography
led to 0.20 g (67%) of cycloadduct 9 as a thick oil and
as the 52–48% mixture of isomers 9B-1 and 9B-2; (M
+ H)+ = 347; (M + H)f+ound = 347.0542 C18H17ClO3P
requires 347.0604 for the 35Cl isotope. IR (film) 1198,
1438, 1610, 1654, 2935 cm−1.
˚
◦
¯
triclinic, space group P1, a = 10.960(5) A, b =
˚
˚
12.766(6) A, c = 9.070(4) A, α = 108.01(3) , β =
◦
◦
3
˚
96.88(4) , γ = 103.33(4) , V = 1149(1) A , Z = 2,
Dc = 1.379 gcm−1, µ(Cu Kꢁ) = 4.007 mm−1; Struc-
ture solution with direct method was carried out
with the teXsan package [20]. Refinement was car-
ried out with SHELXL-97 [21]. Final R indices for 2
are R = 0.0988, RW = 0.1479 (for all 9818 reflections)
and R = 0.0522, RW = 0.1258 (I > 2ꢂ(I)).
The crystallographic data (CCDC 205727) have
been deposited at the Cambridge Crystallographic
Data Centre.

106 Keglevich et al.
[8] Jankowski, S.; Rudzinski, J.; Szelke, H.; Keglevich,
Gy. J Organomet Chem 2000, 595, 109.
PM3 Semiempirical Calculations
The calculations of the heat of enthalpies and ge-
ometries of the substances were performed by PM3
[13,14] implemented in MOPAC93 [12]. The gradi-
ent norms were always less than 0.01 kcal/mol/RA
in the end of the calculations. The force matrices of
the molecules were found to be positive definite sup-
porting that we localized the minima on the energy
surface. In some cases the structures were calculated
by MNDO-d included by HYPERCHEM [22] with the
same options as before. Figures 3 and 4 were created
by MOLDEN [23].
[9] Keglevich, Gy.; Szelke, H.; Tama´s, A. M.; Harmat, V.;
´
Luda´nyi, K.; Vasko´, A. Gy.; To´´ke, L. Heteroat Chem
2002, 13, 626.
´
[10] Keglevich, Gy.; Vasko´, A. Gy.; Dobo´, A.; Luda´nyi, K.;
To´´ke, L. J Chem Soc, Perkin Trans 1 2001, 1062.
[11] Keglevich, Gy.; Kova´cs, J.; Luda´nyi, K.; To´´ke, L. Het
Commun 2002, 8, 31.
[12] Stewart, J. J. P. MOPAC93 (Revision V. 2); Fujitsu Ltd,
Tokyo, 1995.
[13] Stewart, J. J. P. J Comput Chem 1989, 10, 209.
[14] Stewart, J. J. P. J Comput Chem 1989, 10, 221.
[15] Moedritzer, K. Synth React Inorg Met-Org Chem
1974, 4, 119.
[16] Lewis, E. S.; McCortney, B. A. Can J Chem 1986, 64,
1156.
[17] Keglevich, Gy.; Steinhauser, K.; Keseru´´, Gy. M.;
ACKNOWLEDGMENTS
´
Bo¨cskei, Zs.; Ujsza´szy, K.; Marosi, Gy.; Ravadits, I.;
We are indebted to Dr. Gyo¨rgy Marosi and Andrea
Ma´rton for performing the thermal examinations.
The authors are indebted to Dr. Istva´n Pa´linko´ for
performing the MNDO-d calculations.
To´´ke, L. J Organomet Chem 1999, 579, 182.
[18] Keglevich, Gy.; Androsits, B.; To´´ke, L. J Org Chem
1988, 53, 4106.
[19] According to the IUPAC nomenclature, the following
numbering was used for naming the products:
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[20] teXsan for Windows, version 1.06; Molecular
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