New 7-phosphanorbornenes derived from 2-methyl-1-phenyl- And 1-cyclohexyl-3-methyl-2,5-dihydro-1H-phosphole 1-oxides

Article abstract of DOI:10.1002/hc.20097

Novel 7-phosphanorbornene derivatives, such as 4, 5, 10, and 11 were synthesized utilizing 1-phenyl-2-methyl-2,5-dihydro-1H-phosphole oxide (1) and 1-cyclohexyl-3-methyl-2,5-dihydro-1H-phosphole oxide (7) as the starting materials. Products 4 and 10 were

Full text of DOI:10.1002/hc.20097

Heteroatom Chemistry
Volume 16, Number 5, 2005
New 7-Phosphanorbornenes Derived from
2-Methyl-1-phenyl- and 1-Cyclohexyl-3-
methyl-2,5-dihydro-1H-phosphole 1-Oxides
Ja´nos Kova´cs,1 No´ra Bala´zsdi Szabo´,1 Zolta´n Nagy,2
Krisztina Luda´nyi,3 and Gyo¨rgy Keglevich1
1Department of Organic Chemical Technology, Budapest University of Technology and Economics,
H-1521 Budapest, Hungary
2Gedeon Richter Ltd., 1475 Budapest, Hungary
3Hungarian Academy of Sciences, Chemical Research Center, H-1525 Budapest, Hungary
Received 17 December 2004
INTRODUCTION
ABSTRACT: Novel 7-phosphanorbornene deriva-
tives, such as 4, 5, 10, and 11 were synthesized uti-
lizing 1-phenyl-2-methyl-2,5-dihydro-1H-phosphole
oxide (1) and 1-cyclohexyl-3-methyl-2,5-dihydro-1H-
phosphole oxide (7) as the starting materials. Products
4 and 10 were prepared by trapping the corresponding
phosphole oxide intermediates (3 and 9, respectively)
by N-phenylmaleimide, while 5 and 11 were obtained
by the dimerization of 3 and 9, respectively. The
trapping reaction was studied in details; on one hand,
bromo-2,3-dihydro-1H-phosphole oxides (6-1 and
6-2) were pointed out as the intermediates, on the
other hand, the trapping reaction was optimized. Bri-
dged P-heterocycles 4, 5, 10, and 11 were tested in the
fragmentation-related phosphorylation of methanol.
Hydrogenation of phosphanorbornenes 4 and 5 led to
the corresponding phosphanorbornanes (12 and 14,
respectively) and to a reductive type of retro cycload-
P-heterocycles are of current interest due to their
rich chemistry and the different applications.
The 3-methyl-2,5-dihydro-1H-phosphole oxides in-
cluding the P-phenyl derivative available via the
McCormack cycloaddition of isoprene and phos-
phorus halogenides are versatile intermediates of
other P-heterocycles, such as phospholes, phosphi-
nine derivatives (phosphinines themselves and their
dihydro-, tetrahydro-, and hexahydro-derivatives)
[1–4]. The piperylene-based 2-methyl-2,5-dihydro-
1H-phosphole derivatives are less studied [5–7].
Quin introduced the 1-phenyl-2-methyl-2,5-dihydro-
phosphole oxide and studied its double-bond rear-
rangement [5,6]. We examined the possibility of its
ring enlargement by dichlorocarbene and prepared
some of its derivatives including phosphine boranes
[7].
ꢀ
C
dition. 2005 Wiley Periodicals, Inc. Heteroatom Chem
16:320–326, 2005; Published online in Wiley InterScience
(www.interscience.wiley.com). DOI 10.1002/hc.20097
In this paper, new 7-phosphanorbornenes with
skeletal methyl group at the bridgehead carbon atom
or with cyclohexyl group on the phosphorus atom
are synthesized and their fragmentation properties
are studied.
Dedicated to Professor Dr. Alfred Schmidpeter on the occasion
of his 75th birthday.
Correspondence to: G. Keglevich; e-mail: keglevich@oct.mail.
bme.hu.
RESULT AND DISCUSSION
Contract grant sponsor: Hungarian Scientific Research Fund.
Contract grant number: OTKA no. T042479.
Dihydrophosphole oxide 1 was utilized in the prepa-
c
ꢀ
2005 Wiley Periodicals, Inc.
ration of 7-phosphanorbornene derivatives. The key
320

New 7-Phosphanorbornenes Derived from 2-Methyl-1-phenyl- and 1-Cyclohexyl-3-methyl-2,5-dihydro-1H-phosphole 1-oxides 321
intermediate was dibromo-tetrahydrophosphole ox-
ide 2 that was synthesized by the addition of bromine
to the double-bond of 1. The dibromo species 2
was, in fact, formed as four isomers of the possi-
ble eight. The diastereomers of 2 were characterized
by 31P and 13C NMR, as well as mass spectrometry.
Double dehydrobromination of 2 by triethylamine
led to phosphole oxide 3 that was trapped by N-
phenylmaleimide, or was allowed to undergo dimer-
ization to furnish phosphanorbornene derivative 4
or phosphole oxide dimer 5, respectively (Scheme 1).
Optimization of the 2 → 3 → 4 reaction sequence
showed that performing the dehydrobromination
and the subsequent trapping at 26◦C, the dimeriza-
tion can be avoided. Preparation of the dimer 5 can,
however, be efficiently carried out in boiling toluene
in a relatively fast reaction. After purification by col-
umn chromatography, products 4 and 5 were ob-
tained in ca. 62% and were characterized by 31P, 13C,
and 1H NMR as well as mass spectral data.
This experience is unique, as the dimerization of
phosphole oxides is known to be regio-and stereo-
specific [8].
It is noteworthy that interrupting the dehy-
drobromination and the trapping at a conversion
of ∼70%, it was possible to detect 3-bromo-2,3-
dihydrophosphole oxide intermediates 6-1 and 6-2
by 31P NMR (δP (CDCl3) 52.6 and 51.1 in a ratio of
3:1), as well as by MS ((M + H)+ = 271).
In the next stage of our work, novel 7-
phosphanorbornenes (10 and 11) bearing a cyclo-
hexyl group on the phosphorus atom were prepared
from 1-cyclohexyl-2,5-dihydro-1H-phosphole oxide
7, applying the protocols used for the synthesis of
bridged compounds 4 and 5 starting from dihy-
drophosphole oxide 1 (Scheme 2).
The products 10 and 11 were characterized by
31P and 13C NMR, as well as mass spectrometry.
We wished to prepare the fully saturated deriva-
tives of 7-phosphanorbornenes 4 and 5. Catalytic hy-
drogenation of compounds 4 and 5 at 60◦C and 22
bar led to phosphanorbornanes 12 and 14, respec-
tively. It is noteworthy that in the case of the reduc-
tion of 5, the 2,3-dihydrophosphole moiety resisted
the hydrogenation. The hydrogenation of 4 and 5
was, however, accompanied by a reductive type of
In a small portion (24%), another isomer of the
phosphole oxide dimer, was also formed. According
to 13C NMR data, the minor product can be formu-
lated as 5ꢁ.
SCHEME 1

322 Kova´cs et al.
SCHEME 2
retro Diels Alder reaction resulting in the formation
of tetrahydrophosphole oxide 13 as a single diastere-
omer (Schemes 3 and 4). This kind of fragmentation
has only been observed in the mass spectra of some
7-phosphanorbornenes [9].
It is known that the bridging P(O)Y moiety (Y =
Ph, alkyl) of the 7-phosphanorbornenes can be in-
volved in some kind of reactions [2]. In earlier
work, we applied 7-phosphanorbornenes in the UV
light-mediated fragmentation-related phosphoryla-
tion of simple alcohols [10,11]. The new 7-phos-
phanorbornenes (4 and 5) were tested as precursors
of the P(O)Ph moiety. Thermal examinations (TG,
DTG, and DSC) revealed that for 4 and 5, the P-
fragment is ejected at 206 and 242◦C, respectively,
as the optimum temperatures.
The P-cyclohexyl 7-phosphanorbornenes 10 and
11 could also be photolyzed in the presence of
methanol to afford methyl cyclohexyl-H-phosphi-
1
nate 16 with δP 46.3 and JPH = 522 Hz (Scheme 6).
The presence of dihydrophosphindole 17 could also
be detected in the crude reaction mixture (δP 81.5,
[M + H]+ = 263).
It is a novel observation that P-cyclohexyl-
bridged heterocycles underwent UV light-mediated
transformations.
Based on our previous experiences [10,11], and
in contrast to Tomioka’s suggestion [13,14], we as-
sumed the fragmentation-related phosphorylation to
take place via an intermediate with a pentavalent
Photolysis of the bridged P-heterocycles 4 and
5 in acetonitrile in the presence of methanol led to
methyl phenyl-H-phosphinate 15 in good yield that,
1
on the basis of its δP shift of 27.8 and JPH coupling
of 567 Hz, could be well identified [12] (Scheme 5).
SCHEME 3
SCHEME 4

New 7-Phosphanorbornenes Derived from 2-Methyl-1-phenyl- and 1-Cyclohexyl-3-methyl-2,5-dihydro-1H-phosphole 1-oxides 323
column chromatography (silica gel, 3% methanol in
chloroform) afforded 7.6 g (83%) of 2 as a mixture of
2-1 (44%), 2-2 (22%), 2-3 (20%), and 2-4 (14%). HR-
MS, (M + H)+found = 350.9125, C11H14OPBr2 requires
350.9149.
2-1: 31P NMR (CDCl3) δ 52.0; 13C NMR (CDCl3)
SCHEME 5
δ10.4 (J = 1.7, C(2) Me), 37.1 (J = 66.9, C(2)), 37.7
(J = 61.4, C(5)), 49.8 (J = 5.0, C(4)),a 60.0 (J =
7.2, C(3)),a 128.8 (J = 12.1, C(3ꢁ)),b 130.4 (J = 10.8
C(2ꢁ)),b 132.0 (J = 2.6, C(4ꢁ)), 138.1 (J = 86.9, C(1ꢁ)).
2-2: 31P NMR (CDCl3) δ 47.2; 13C NMR (CDCl3) δ
11.8 (C(2) Me), 37.9 (J = 64.2, C(5)), 45.9 (J = 59.1,
C(2)), 49.7 (J = 9.1, C(4)),c 59.9 (J = 18.9, C(3)),c
128.5 (J = 12.2, C(3ꢁ)),d 130.3 (J = 9.8, C(2ꢁ)),d 130.4
(J = 96.0, C(1ꢁ)), 132.7 (J = 1.9, C(4ꢁ)).
pentacoordinate phosphorus atom formed by the ad-
dition of methanol on the P O group of the precur-
sor 4 and 5 and not through an elimination-addition
mechanism involving phosphinidine PhP(O) as an
intermediate.
To summarize our results, new 7-phosphanor-
bornenes with skeletal methyl group(s) in unusual
position(s) or with cyclohexyl group(s) on the
phosphorus atom(s) were synthesized and tested
in fragmentation–related phosphorylations. Hydro-
genation of 7-phosphanorbornenes led to the cor-
responding phosphanorbornanes and to a reductive
type of retro cycloaddition.
2-3: 31P NMR (CDCl3) δ 42.6; 13C NMR (CDCl3)
δ 10.5 (J = 3.0, C(2) Me), 40.0 (J = 56.4, C(5)),
44.6 (J = 60.2, C(2)), 49.3 (J = 4.6, C(4)),e 60.8 (J =
15.8, C(3)),e 128.7 (J = 12.3, C(3ꢁ)),f 129.6 (J = 10.0,
C(2ꢁ)),f 130.1 (J = 95.8, C(1ꢁ)), 132.1 (C(4ꢁ)).
2-4: 31P NMR (CDCl3) δ 53.1; 13C NMR (CDCl3) δ
13.0 (C(2) Me), 35.4 (J = 62.8, C(5)), 38.9 (J = 64.8,
C(2)), 49.4 (J = 9.2, C(4)),g 61.0 (J = 10.7, C(3)),g
128.3 (J = 12.3, C(3ꢁ)),h 131.3 (J = 9.9, C(2ꢁ)),h 132.5
(J = 2.2, C(4ꢁ)); a−h may be reversed.
The 1-methyl-7-phosphanorbornene derivatives
may be useful starting materials in Baeyer–Villiger
oxidations. The presence of the methyl group in po-
sition 1 is expected to influence the course and the
result of the reaction.
1-Methyl-10-oxo-4,10-diphenyl-4-aza-phospha-
EXPERIMENTAL
The 31P-, 13C-, and H-NMR spectra were taken on
bicyclo[5.2.1.02,6]dec-8-ene-3,5-dione (4) [15]
1
2.7 mL (19.6 mmol) of triethylamine was added to
the 50 mL of toluene solution of 3.2 g (8.9 mmol) of
2 and 1.9 g (11.1 mmol) of NFMI. After 6 days of stir-
ring at room temperature, the mixture was heated
at the boiling point for 4 h. After filtration, the fil-
trate was evaporated and the crude product so ob-
tained was purified by column chromatography (sil-
ica gel, 3% methanol in chloroform) to afford 2.0 g
(60%) of 4. 31P NMR (CDCl3) δ 87.5; 13C NMR (CDCl3)
δ 12.0 (C(1) Me), 42.6 (J = 63.5, C(4)), 44.6 (J =
12.8, C(5)),a 48.2 (J = 14.3, C(6)),a 51.1 (J = 67.6,
C(1)), 124.7 (J = 87.8, C(1ꢁ)), 126.3 (C(3ꢁꢁ)),b 128.4
(J = 11.0, C(3ꢁ)),c 128.5 (C(4ꢁꢁ)), 128.9 (C(2ꢁꢁ)),b 130.5
(J = 10.5, C(3)), 131.4 (C(1ꢁꢁ)), 132.3 (J = 1.9, C(4ꢁ)),
132.9 (J = 7.9, C(2ꢁ)),c 135.4 (J = 13.7, C(2)), 174.4
(J = 14.2 C(8)),d 174.6 (J = 13.4, C(10))d; a−d may be
reversed; 1H NMR (CDCl3) δ 1.81 (d, 3H, Me), 3.83 (s,
1H, CH), 3.85 (s, 1H, CH), 6.17 (m, 1H, CH), 7.13–
7.80 (10H, Ar H); HR-MS, (M + H)+found = 364.1103,
C21H19NO3P requires 364.1037.
a Bruker DRX-500 spectrometer operating at 202.4,
160.4 125.7, and 500 MHz, respectively. Chemical
shifts are downfield relative to 85% H3PO4 or TMS.
The couplings are given in Hz. FAB mass spectrom-
etry was performed on a ZAB-2SEQ instrument.
The 2-methyl-1-phenyl-2,5-dihydro-1H-phos-
phole oxide (1) was prepared as described earlier [5].
3,4-Dibromo-2-methyl-1-phenyl-2,3,4,5-
tetrahydro-1H-phosphole 1-oxide (2)
1.5 mL (28.6 mmol) of bromine in 15 mL of chloro-
form was added to the 50 mL of chloroform solution
of 5.0 g (26.0 mmol) of dihydrophosphole oxide 1
at 0◦C. After 0.5 h of stirring, the mixture was al-
lowed to warm up to room temperature and the stir-
ring was continued for 4 h. Volatile components were
then removed. Purification of the crude product by
3,10-Diphenyl-4,7-dimethyl-3,10-diphosphatri-
cyclo[5.2.1.02,6]deca-4,8-diene-3,10-dioxide
(5) [15]
3.4 mL (24.4 mmol) of triethylamine was added to
the 35 mL of toluene solution of 3.9 g (11.1 mmol)
SCHEME 6

324 Kova´cs et al.
of 2. The mixture was stirred at 110◦C for a day,
and for other 2 days at rt. After filtration, the fil-
trate was evaporated. The purification of the crude
product by column chromatography (silica gel, 2%
methanol in chloroform) led to 1.5 g of light yel-
low oil, containing dimers 5 (94%) and 5ꢁ (6%). The
fraction was further purified by column chromatog-
raphy to furnish 1.3 g (62%) of dimer 5. 31P NMR
(CDCl3) δ 57.0 (P(1)), 83.1 (P(8)), J = 35.1; 13C NMR
(CDCl3) δ 11.7 (C(2) Me),a 12.8 (J = 11.6, C(4)–
Me),a 41.2 (Jꢁ = 76.3, Jꢁꢁ = 11.5, C(7a)), 41.6 (Jꢁꢁ =
60.2, C(7)), 51.3 (Jꢁꢁ = 70.0, C(4)), 53.3 (Jꢁ = 13.3,
Jꢁꢁ = 13.4, C(3a)), 126.3 (J = 85.6, C(1ꢁ)),b 128.1 (J =
10.8, C(3ꢁ)),c 128.4 (J = 11.8, C(3ꢁꢁ)),c 130.2 (J = 10.3,
C(2ꢁ)),c 131.7 (C(4ꢁ), C(4ꢁꢁ)), 131.9 (J = 95.3, C(1ꢁꢁ)),b
130.0 (J = 8.5, C(6)), 132.8 (J = 7.7, C(2ꢁꢁ)),c 132.9
(Jꢁꢁ = 7.2, C(5)), 139.8 (Jꢁ = 90.3, C(2)), 140.8 (Jꢁ =
30.3, Jꢁꢁ = 8.6, C(3)); a−cmay be reversed; Jꢁ: cou-
0.12 mol) [16]. After 4 h of reflux, the mixture was
stirred at rt overnight. The mixture was treated with
concentrated hydrochloric acid (10 mL) in water
(100 mL). The extraction with chloroform led to
15.2 g (64%) of 1H-phosphole oxide 7. The crude
product was purified by fractional distillation to give
5.9 g (25%) of 7. bp 115–117◦C (0.12 Hg mm); mp
63–64◦C (10% chloroform in toluene), colorless, hy-
groscopic crystals.
7: 31P NMR (CDCl3) δ 73.1; 13C NMR (CDCl3) δ
20.2 (J = 10.1, C(3) Me), 25.2 (J = 2.8, C(2ꢁ) and
C(6ꢁ)), 25.9 (J = 1.2, C(4ꢁ)), 26.2 (J = 13.1, C(3ꢁ) and
C(5ꢁ)), 30.2 (J = 61.3, C(5)),a 33.4 (J = 64.1, C(2)),a
38.5 (J = 64.5, C(1ꢁ)), 120.9 (J = 6.9, C(4)), 136.9
(J = 11.7, C(3)); amay be reversed; 1H NMR (CDCl3)
δ 1.67 (s, 3H, Me), 5.38–5.55 (m, 1H, C(4) H);
HR-MS (M + H)+found = 199.1237, C11H20PO requires
199.1252.
1
pled by P(1), Jꢁꢁ: coupled by P(8); H NMR (CDCl3)
δ 1.65 (d, JPH = 16.0, 3H, Me), 1.82 (d, JPH = 11.5,
3H, Me), 3.46 (d, 1H, JHH = 8, C(7a) H), 3.61 (s,
1H, C(7) H), 3.95 (m, 1H, C(3a) H), 5.79 (dd, 1H,
3,4-Dibromo-1-cyclohexyl-3-methyl-2,3,4,5-
tetrahydro-1H-phosphole 1-Oxide (8)
JHH = 7.0, JPH = 11.0, C(5) H), 6.47 (d, 1H, JPH
=
0.5 mL (9.8 mmol) of bromine in 5 mL of chloro-
form was added to the 35 mL of chloroform solution
of 1.6 g (8.1 mmol) of 7 at 0◦C. After 0.5 h of stir-
ring, the mixture was allowed to warm up to room
temperature and the stirring was continued for 4 h.
Volatile components were then removed. Purifica-
tion of the crude product by column chromatogra-
phy (silica gel, 3% methanol in chloroform) afforded
2.8 g (93%) of 8 as the mixture of two isomers (A and
B). HR-MS (M + H)+found = 356.9607, C11H20PO79Br2
requires 356.9616.
41.0, C(3) H), 6.62 (m, 1+H, C(6) H), 7.40–7.72 (10H,
Ar H); HR-MS: (M + H)found = 381.1115, C22H23P2O2
requires 381.1173.
The other fraction (0.20 g) consisted of 76% 5
and 24% 5ꢁ.
5ꢁ: 31P NMR (CDCl3) δ 56.1 (P1), 81.8 (P8), J =
35.8; 13C NMR (CDCl3) δ 12.3 (J = 11.7, C(4) Me),a
12.6 (C(2) Me),a 44.6 (Jꢁꢁ = 65.9, C(7)), 46.1 (Jꢁ =
75.9, Jꢁꢁ = 12.7, C(7a)), 48.7 (Jꢁ = 13.0, Jꢁꢁ = 13.0,
C(3a)), 50.9 (Jꢁ = 2.5, Jꢁꢁ = 65.6, C(4)), 125.8 (J =
10.4, C(6)), 128.4 (J = 10.8, C(3ꢁ)),b 128.7 (J =
11.6, C(2ꢁ)),b 128.8 (J = 11.8, C(3ꢁꢁ)),b 130.3 (J =
8.9, C(2ꢁꢁ)),b C(1ꢁ) overlapped at around 131,c 132.0
(C(4ꢁ), C(4ꢁꢁ)), 133.2 (J = 95.1, C(1ꢁꢁ)),c 137.5 (Jꢁ =
5.3, Jꢁꢁ = 13.3, C(5)), 139.3 (Jꢁ = 90.1, Jꢁꢁ = 4.2, C(2)),
143.0 (Jꢁ = 30.2, Jꢁꢁ = 10.5, C(3)); a−cmay be reversed;
8A: 31P NMR (CDCl3) δ 61.8; 13C NMR (CDCl3)
δ 24.1 (J = 7.9, C(2ꢁ)), 25.0 (C(4ꢁ)), 25.4 (J = 13.6,
C(3ꢁ)), 30.8 (J = 5.7, C(3) Me), 35.4 (J = 55.8, C(5)),
39.7 (J = 67.5, C(1ꢁ)), 40.8 (J = 56.2, C(2)), 57.2 (J =
1
5.6, C(4)), 66.8 (J = 6.7, C(3)); H NMR (CDCl3) δ
2.15 (s, 3H, Me), 2.42–2.51 (m), 2.59–2.71 (m), 2.88–
2.95 (m), 4H, 2CH2, 4.60–4.68 (m, 1H, C(4) H).
8B: 31P NMR (CDCl3) δ 66.0; 13C NMR (CDCl3)
δ 24.2 (J = 11.7, C(2ꢁ)), 25.0 (C(4ꢁ)), 25.3 (J = 13.6,
C(3ꢁ)), 32.4 (J = 9.4, C(3) Me), 36.5 (J = 57.2, C(5)),
39.7 (J = 60.7, C(2)), 41.3 (J = 68.1, C(1ꢁ)), 50.9 (J =
4.4, C(4)), 67.1 (J = 4.8, C(3)).
1
Jꢁ: coupled by P(1), Jꢁꢁ: coupled by P(8); H NMR
(CDCl3) δ 1.71 (d, JPH = 16.0, 3H, Me), 1.80 (d, JPH
=
9.0, 3H, Me), 3.21 (d, 1H, JHH = 8.0, CH, C(7a) H),
3.43 (s, 1H, CH, C(7) H), 4.28 (m, 1H, C(3a) H), 6.07
(m, 1H, C(6) H), 6.39 (d, 1H, JPH = 42.5, C(3) H),
6.48 (dd, 1H, JHH = 7.5, JPH = 12.5, C(5) H), 7.35–
7.73 (10H, Ar H).
3,10-Dicyclohexyl-5,8-dimethyl-3,10-diphos-
phatricyclo[5.2.1.02,6]deca-4,8-diene-3,10-
dioxide (11) [15]
Synthesis of 3-Methyl-1-cyclohexyl-2,5-dihydro-
1H-phosphole Oxide (7)
The Grignard reagent prepared from magnesium
(8.4 g, 0.36 mol) and cyclohexylbromide (24.5 g,
0.15 mol) in THF (100 mL) was added dropwise with
cooling to the THF solution (100 mL) of 1-chloro-
2,5-dihydro-3-methyl-1H-phosphole 1-oxide (18.6 g,
1.4 mL (10.1 mmol) of triethylamine was added to
the 25 mL of toluene solution of 1.51 g (4.24 mmol)
of 8. The mixture was stirred at 110◦C for 3 days.
After filtration, the filtrate was evaporated and the

New 7-Phosphanorbornenes Derived from 2-Methyl-1-phenyl- and 1-Cyclohexyl-3-methyl-2,5-dihydro-1H-phosphole 1-oxides 325
crude product so obtained was purified by column
chromatography (silica gel, 2% methanol in chlo-
roform) to furnish 0.60 g (72%) of dimer 11. 31P
NMR (CDCl3) δ 68.7 (P(2)), 94.0 (P(8)), J = 32.0;
13C NMR (CDCl3) δ 18.5 (Jꢁ = 15.8, C(3) Me), 18.7
(Jꢁꢁ = 3.6, C(5) Me), 28.5 (Jꢁ = 63.0, C(1ꢁ)),a 39.0
(J = 71.6, C(1ꢁꢁ)),a 34.9 (Jꢁ = 70.9, Jꢁꢁ = 9.5, C(7a)),
39.8 (J = 2.5, J = 53.1, C(7)),b 46.0 (J = 59.0, C(4)),b
51.7 (Jꢁ = 10.8, Jꢁꢁ = 10.8, C(3a)), 121.8 (Jꢁ = 92.4,
C(2)), 123.4 (Jꢁ = 8.6, Jꢁꢁ = 4.9, C(6)), 134.8 (Jꢁꢁ =
11.4, C(5)), 158.5 (Jꢁ = 21.1, Jꢁꢁ = 8.4, C(3)); a,bmay
be reversed; Jꢁ: coupled by P(1), Jꢁꢁ: coupled by
P(8); 1H NMR (CDCl3) δ 1.76 (s, 3H, Me), 1.93
(s, 3H, Me), 2.96 (s, 1H, C(7) H), 3.09 (s, 1H,
C(4) H), 3.10 (d, Jꢁ = 6.0, 1H, C(7a) H), 3.77 (m,
1H, C(3a) H), 5.80 (d, Jꢁ = 23.9, 1H, C(2) H), 6.10
tered, and the volatile components were removed.
The crude product so obtained was purified by col-
umn chromatography (silica gel, 2% methanol in
chloroform) to provide 0.24 g (61%) of phosphanor-
bornane 14 and 0.10 g (25%) of tetrahydrophosphole
oxide 13 as a single diastereomer.
13: 31P NMR (CDCl3) δ 58.8, 13C NMR (CDCl3) δ
11.7 (J = 3.1, C(2) Me), 23.2 (J = 6.3, C(3)),a 29.7
(J = 66.0, C(5)), 33.6 (J = 10.6, C(4)),a 35.0 (J =
69.1, C(2)), amay be reversed; MS, (M + H)+ = 195.1
[7].
14: 31P NMR (CDCl3) δ 57.7 (P(1)), 62.1
(P(8)), J = 40.0; 13C NMR (CDCl3) δ, 12.7 (J =
11.0, C(4) Me),a 14.0 (C(2) Me),a 18.4 (J = 6.5,
C(6)), 24.6 (Jꢁꢁ = 14.9, C(5)), 34.6 (J = 62.7, J =
3.0, C(7a)),b 37.7 (Jꢁꢁ = 72.2, C(7)), 43.2 (Jꢁꢁ = 71.1,
C(4)), 49.9 (J = 4.9, J = 12.7, C(3a)),b 128.5 (J =
85.1, C(1ꢁ)),c 128.6 (J = 11.9, C(3ꢁꢁ)),d 129.0 (J =
11.2, C(3ꢁ)),d 130.1 (J = 10.2, C(2ꢁꢁ)),d 130.4 (J =
9.1, C(2ꢁ)),d 131.8 (J = 2.7, C(4ꢁ)),e 132.1 (J = 95.9,
C(1ꢁꢁ)),c 132.2 (J = 2.5, C(4ꢁꢁ)),e 139.4 (Jꢁ = 89.2,
C(2)), 142.3 (Jꢁ = 30.0, Jꢁꢁ = 9.5, C(3)); a−emay be re-
versed; Jꢁ: coupled by P(1), Jꢁꢁ: coupled by P(8); HR-
MS: (M + H)+found = 383.1303, C22H25P2O2 requires
383.1330.
(d, Jꢁꢁ = 12.8, 1H, C(6) H); HR-MS (M + H)+found
393.2083, C22H35P2O2 requires 393.2112.
=
9-Methyl-10-oxo-10-cyclohexyl-4-aza-phospha-
bicyclo[5.2.1.02,6] dec-8-ene-3,5-dione (10) [15]
The mixture of 1.05 g (2.9 mmol) of 8, 0.59 g (3.4
mmol) of NFMI, and 0.9 mL (6.5 mmol) of triethy-
lamine in 25 mL of toluene was stirred at 26◦C.
After 6 days of stirring, the mixture was heated
at the boiling point for 2 h. After filtration, the
filtrate was evaporated and the crude product so
obtained was purified by column chromatography
(silica gel, 2% methanol in chloroform) to afford
0.88 g (81%) of phosphanorbornene 10. mp 165–
166◦C (10% chloroform in toluene), colorless crys-
tals; 31P NMR (CDCl3) δ 98.4; 13C NMR (CDCl3) δ
19.5 (J = 3.3, C(2) Me), 25.4 (J = 1.0, C(4ꢁ)), 26.1
(J = 6.2) and 26.3 (J = 6.2, C(3ꢁ)),a 26.8 (J = 7.0)
and 26.9 (J = 6.8, C(2ꢁ)),a 29.6 (J = 59.9, C(1ꢁ)), 42.7
(J = 56.6, C(4)),b 43.8 (J = 10.0, C(5)),c 45.1 (J =
11.6, C(6)),c 45.9 (J = 56.1, C(1)),b 121.8 (J = 8.8,
C(3)), 126.6 (C(2ꢁꢁ)),a 129.0 (C(4ꢁꢁ)), 129.4 (C(3ꢁꢁ)),a
131.8 (C(1ꢁꢁ)), 140.9 (J = 10.7, C(2)), 175.5 (J = 12.2,
C(8)),d 175.8 (J = 12.8, C(10))d; a−dmay be reversed;
1H NMR (CDCl3) δ 1.59 (s, 3H, Me), 3.30–3.34
(m, 1H, C(6) H), 3.43–3.49 (m, 1H, C(5) H), 3.95–
4.03 (m, 2H, C(1) H, C(4) H), 5.86–5.93 (m, 1H,
C(3) H), 7.09–7.14 (m, 2H, Ar H), 7.35–7.49 (m, 3H,
Ar H); HR-MS (M + H)+found = 370.1542, C21H25PO3N
requires 370.1572.
Phosphanorbornene 4 was hydrogenated under
similar conditions to afford 0.10 g (26%) of phos-
phanorbornane 12 and 0.16 g (76%) of tetrahy-
drophosphole 13 after the work-up.
12: 31P NMR (CDCl3) δ 62.8; 13C NMR (CDCl3)
δ 14.4 (C(1) Me), 18.6 (J = 8.1, C(3)),a 25.5 (J =
13.7, C(2)),a 34.6 (J = 65.3, C(4)), 43.4 (J = 68.7,
C(1)), 43.7 (J = 3.0, C(5)),b 48.1 (J = 5.0, C(6)),b
126.5 (C(3ꢁꢁ)),c 127.5 (J = 88.1, C(1ꢁ)), 128.9 (C(4ꢁꢁ)),
129.2 (C(2ꢁꢁ)),c 129.3 (J = 11.5, C(3ꢁ)),d 130.6 (J =
9.3, C(2ꢁ)),d 131.7 (C(1ꢁ)), 132.9 (J = 2.7, C(4ꢁ)),
175.7 (J = 15.2, C(8)),e 176.1 (J = 14.8, C(10))e;
a−emay be reversed; HR-MS: (M + H)f+ound = 366.1235,
C21H21NO3P requires 366.1259.
Photoinduced Fragmentation-Related
Phosphorylation Using 7-Phosphanorbornenes
(4, 5, 10, and 11)
The solution of 0.3 mmol of cycloadduct 4, 5, 10, or
11 in the mixture of 40 mL of acetonitrile and 4 mL of
methanol was irradiated with a 125 W mercury lamp
in a photochemical quartz reactor for 1 h at 26◦C.
Volatile components were removed, and the residue
so obtained was purified by flash column chromatog-
raphy (silica gel, 2% methanol in chloroform) to give
H-phosphinate 15 or 16, respectively, in a yield of
89–95%.
Catalytic Hydrogenation of
7-Phosphanorbornene Derivative (5)
0.39 g (1.02 mmol) of 5 in 40 mL of methanol was
hydrogenated in the presence of 0.30 g of (10%) Pd/C
at 60◦C and at 22 bar for 14 h. The mixture was fil-
15: 31P NMR (CDCl3) δ 27.8, JPH = 567 Hz (δ [11]
26.8, JPH = 568 Hz); MS, (M + H)+ = 157.1.

326 Kova´cs et al.
16: 31P NMR (CDCl3) δ 46.3, JPH = 522 Hz (δ [17]
[10] Keglevich, Gy.; Luda´nyi, K.; Quin, L. D. Heteroatom
Chem 1997, 8, 135.
[11] Keglevich, Gy.; Trecska, M.; Nagy, Z.; To´´ke, L. Het-
eroatom Chem 2001, 12, 6.
46.7, JPH = 521 Hz).
[12] Quin, L. D.; Jankowski, S.; Rudzinski, J.; Sommese,
A. G.; Wu, X. P. J Org Chem 1993, 58, 6212.
[13] Tomioka, H.; Hirani, Y.; Izawa, Y. Tetrahedron Lett
1974, 1865.
[14] Tomioka, H.; Hirani, Y.; Izawa, Y. Tetrahedron Lett
1974, 4477.
ACKNOWLEDGMENT
´
G. K. and J. K. are grateful to Dr Aron Szo¨llo¨sy
(Budapest University of Technology and Economics)
for his advice.
[15] According to the IUPAC nomenclature, the following
numbering was used for naming products 4, 5, 10,
and 11:
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[6] Quin, L. D.; Barket, T. P. Chem Commun 1967, 914.
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