Reactivity of a 1,3,2-diazaphosphinine toward propargyl-phosphine derivatives and activated alkenes

Article abstract of DOI:10.1002/hc.10152

2,5-Diphenylphosphole and diphenylphosphino derivatives 2, 3 of 1-phenylpropargyl were prepared by reacting the corresponding diphenylphos-phinolithium and 2,5-diphospholyl lithium salts with (3-bromo-prop-1-ynyl)-benzene in THF at low temperature. Sulfur

Full text of DOI:10.1002/hc.10152

Heteroatom Chemistry
Volume 14, Number 4, 2003
Reactivity of a 1,3,2-Diazaphosphinine
Toward Propargyl-Phosphine Derivatives
and Activated Alkenes
Nicole Maigrot, Mohand Melaimi, Louis Ricard, and Pascal Le Floch
Laboratoire He´teroe´le´ments et Coordination, UMR CNRS 7653, De´partement de Chimie,
Ecole Polytechnique, 91128 Palaiseau Cedex, France
Received 5 December 2002; revised 17 December 2002
acrylate, dimethyl fumarate, and acrylonitrile. The
ABSTRACT: 2,5-Diphenylphosphole and diphenyl-
X-ray structure of the cyano derivative 18a is also pre-
phosphino derivatives 2, 3 of 1-phenylpropargyl were
ꢀ
C
sented. 2003 Wiley Periodicals, Inc. Heteroatom Chem
prepared by reacting the corresponding diphenylphos-
14:326–333, 2003; Published online in Wiley InterScience
phinolithium and 2,5-diphospholyl lithium salts with
(www.interscience.wiley.com). DOI 10.1002/hc.10152
(3-bromo-prop-1-ynyl)-benzene in THF at low temper-
ature. Sulfurization of these propargyl derivatives was
then carried out with elemental sulfur in toluene at
90◦C to yield the corresponding phosphole 8 and phos-
phino 9 derivatives. Reaction of 3,5-di-tert-butyl-
INTRODUCTION
Diels–Alder reactions of 1,3,2-diazaphosphinines
with alkynes prove to be a powerful and versatile
method for the synthesis of phosphinines [1]. Over
the last few years we exploited this approach in the
elaboration of different polyfunctional phosphinine-
based structures such as bi-/tridentate, tripodal lig-
ands and macrocycles having different cavity sizes
[2]. Some of these ligands have found interesting ap-
plications in coordination chemistry because of their
strong ꢀ-acceptor capacity [3]. Recently, we showed
that 2,6-bis(diphenylphosphino)phosphinines could
be used as precursor in the synthesis of a new class
of S P S based pincer ligands featuring a central
ꢁ4,ꢂ5-phosphorus atom. Palladium(II) complexes of
these ligands, such as those depicted in the follow-
ing scheme, showed an interesting catalytic activity
in the formation of C B bonds through the Myaura-
catalyzed process [4].
1,3,2-diazaphosphinine 1 with the free phosphole deri-
vative led to a mixture of diazaphosphinines 4 and 5
that were converted to the corresponding phosphinines
6 and 7 upon treatment with trimethylsilylacetylene
in excess. Reaction of 1 with 1-phenylpropargyl
derivatives of diphenylphosphine 8 and phosphole 9
afforded 7,8-dihydro-1-phospha-2,6-diazabarrelenes
10 and 11 having an exocyclic double bond. Forma-
tion of these compounds results from a (1,3)-shift of
a hydrogen atom from the methylene carbon atom
to the bridge of the barrelene moiety. Depending on
the nature of the phosphine group, the sulfur atom
can also be displaced to the P atom of the barrelene
moiety. The X-ray structure of the phosphole derivative
10 was recorded. Three 6,7-dihydro-1-phospha-2,6-
diazabarrelenes bearing two (16) or one ester (17a,b),
or one cyano group (18a,b) on the bridge were also
synthesized through the reaction of 1 with ethyl
Correspondence to: Pascal Le Floch; e-mail: lefloch@poly.
polytechnique.fr.
Contract grant sponsor: CNRS.
Contract grant sponsor: Ecole Polytechnique.
2003 Wiley Periodicals, Inc.
c
ꢀ
326

Reactivity of a 1,3,2-Diazaphosphinine Toward Propargyl-Phosphine Derivatives and Activated Alkenes 327
As a logical extension, we recently explored the
synthesis of extended pincer ligands featuring a
methylene group between the phosphinine ring and
the pendant phosphine ligands. Following a simi-
lar strategy, we thus explored the reactivity of 1,3,2-
diazaphosphinines toward phosphine derivatives of
propargyl. This study led to unexpected results that
prompted us to explore the reactivity of activated
alkenes toward 1,3,2-diazaphosphinines. Herein we
report on these results.
RESULTS AND DISCUSSION
The reactivity of diazaphosphinine 1 toward propar-
gylphosphines was tested using the phosphole
2 and the phosphine 3 derivatives. Syntheses
of these two compounds were achieved by re-
acting 1-phenylethynyl-lithium [5] and the 2,5-
diphenylphospholyl-lithium [6] derivatives with
(3-bromo-prop-1-ynyl)-benzene in THF at low tem-
perature [7]. Compounds 2 and 3 were isolated
in good yields. Phosphole 2 was characterized
by NMR spectroscopy, mass spectrometry, and
elemental analysis. The phosphine derivative 3
proved to be highly oxygen-sensitive and was
characterized by 31P NMR exclusively. As seen
later, 3 was fully characterized as its P-sulfide
derivative.
In order to definitively establish the formula-
tion of 1,2-azaphosphinines 4 and 5, the crude mix-
ture was reacted with trimethylsilylacetylene to yield
phosphinines 6 and 7, which, according to 31P NMR
spectroscopy, were formed in a 4:1 ratio, respectively.
The mechanism of these transformations involves a
mechanism similar to that depicted in the follow-
ing scheme for the formation of diazaphosphinines
4 and 5. A cycloaddition of 1 equiv. of trimethylsi-
lyl acetylene takes place to yield an azaphosphabar-
relene that eliminates 1 equiv. of pivalonitrile. Un-
fortunately, the separation of 6 and 7 could not be
achieved by column chromatography and these two
phosphinines were characterized as a mixture. The
3
presence of a JPP = 20.64 Hz coupling constant in
6 confirms the presence of the methylenephosphole
group at the ꢃ-positions of phosphorus. These two
1
phosphinines were only characterized by H NMR
spectroscopy and mass spectroscopy. The use of
propargylphosphine 2 in place of 3 yielded a simi-
lar result.
Thermal reaction of 1 with 2 and 3 did not
yield the expected result and, whatever the exper-
imental conditions used (temperature, concentra-
tion), the cycloaddition of 1 equiv. of alkyne led
to a mixture of two 1,2-azaphosphinines (4 and
5). As reported in precedent studies, formation of
these two diazaphosphinines occurs through a [4 +
2] cycloaddition/cycloreversion sequence that in-
volves the transient formation of diazaphosphaber-
relenes, followed by the release of one molecule
of pivalonitrile. Thus, the reaction of phosphole
2 with 1 equiv. of 1 in toluene at 110◦C for
40 h afforded 1,2-azaphosphinines 4 and 5, which
were identified by 31P NMR exclusively. On the
basis of 31P NMR data, compounds 4 and 5 are
formed in a 4:1 ratio. The formulation of com-
pound 4 was evidenced by a 3 JPP = 24.26 Hz coupling
constant.
In view of these results, we anticipated that the
steric bulk around the phosphine group could en-
hance the regioselectivity in favor of the forma-
tion of the ꢃ-substituted phosphinine. Indeed, previ-
ous studies have clearly showed that alkynyl carbon
atoms bearing bulky susbtituents are usually bound
to phosphorus in the final compound [1,2]. Thus, 2
and 3 were reacted with elemental sulfur to form
sulfides 8 and 9, which were isolated as stable yel-
low solids and successfully characterized by NMR
techniques and elemental analyses.

328 Maigrot et al.
2,6-diaza-1-phosphabarrelene through a (1,3)-shift
of one methylene proton. Another surprising feature
is the transfer of the sulfur atom from the phosphole
ring to the phosphorus atom of the dihydrophos-
phabarrelene unit.
Reaction of 1 with 8 and 9 led to a surpris-
ing result. Contrary to what is usually observed
when alkynes are reacted with diazaphosphinines,
the formation of 1,2-azaphosphinines was not ob-
served. Thus, reaction of 1 with 8 cleanly afforded
compound 10, which is characterized by an AB
spin system in 31P NMR spectroscopy. The formu-
lation of 10 could not be directly established on
1H and 13C NMR data. Fortunately, single crystals
could be grown and the X-ray structure could be
recorded. An ORTEP view of one molecule of 10 is
presented in Fig. 1 and the most significant bond
lengths and bond angles are also listed. As can be
seen, the structure of 10 results from the cycloaddi-
tion of 1 equiv. of 8 on the diazaphosphinine skele-
ton but the expected 2,6-diaza-1-phosphabarrelene
structure has been isomerized into a 7,8-dihydro-
The formation of 10 resulted from the reaction
of the corresponding 1-(2,5-diphenylphospholyl)-3-
phenyl-allene with 1. However, the formation of this
allene as intermediate can be ruled out. Several ex-
periments, carried out under the experimental con-
ditions used for the synthesis of 10, showed that no
isomerization of compound 8 occurs even at high
temperature (150◦C). Therefore, we must admit that
the formation of 10 results from a two-step process
that involves first the cycloaddition then the rear-
rangement. On the basis of this result, it is very diffi-
cult to establish whether this rearrangement is pro-
moted by the transfer of the sulfur atom or not.
Reaction of 1 with the phosphine sulfide 9 led
to a slightly different result and shed some light on
the role played by the transfer of the sulfur atom.
For example, heating equimolar amounts of the two
compounds in toluene at 80◦C for 3 h resulted in
the formation of compound 11 that exhibited an
AB spin system in 31P NMR spectroscopy. However,
chemical shifts of the two phosphorus moieties (δ
(toluene) = 27.70 and 28.60 ppm with 3 JPP = 39.0 Hz)
were found to be rather different from that recorded
for compound 10. Indeed, a similar rearrangement
such as that observed in the synthesis of 10 should
lead to a structure incorporating a dihydrobarre-
lene sulfide (δ (toluene) = −51.40 ppm in 10) moiety
and a free diphenylphosphino group (δ (toluene) =
−13.10 ppm in 3).
FIGURE 1 ORTEP drawing of one molecule of 10 (50%
ellipsoid probability). Hydrogen atoms are omitted for clarity.
˚
Relevant bond lengths (A) and angles (deg) data: S(1)
P(1), 1.9186(6); P(1) N(1), 1.697(1); P(1) N(2), 1.709(1);
P(1) C(5), 1.818(2); P(2) C(7), 1.805(2); P(2) C(10),
1.815(2); P(2) C(6), 1.823(2); N(1) C(1), 1.289(2);
N(2) C(3), 1.286(2); C(1) C(2), 1.527(2); C(2) C(4),
1.589(2); C(4) C(5), 1.517(2); C(5) C(6), 1.334(2);
C(2) C(3), 1.525(2); C(7) C(8), 1.359(3); C(8) C(9),
1.436(3); C(3) C(15), 1.521(2); N(1) P(1) N(2), 104.54(7);
N(1) P(1) C(5), 100.59(7); N(2) P(1) C(5), 97.66(7);
N(1) P(1) S(1), 116.27(5); N(2) P(1) S(1), 115.97(5);
C(5) P(1) S(1), 118.94(6); C(1) N(1) P(1), 113.3(1);
N(1) C(1) C(2), 118.4(1); C(3) C(2) C(1), 109.4(1);
C(3) C(2) C(4), 106.0(1); C(1) C(2) C(4), 108.0(1);
N(2) C(3) C(2), 119.1(1); C(6) C(5) C(4), 130.0(2);
C(6) C(5) P(1), 119.1(1); C(5) C(6) P(2), 131.0(1).
Unfortunately, several attempts to purify by col-
umn chromatography resulted in the isolation of

Reactivity of a 1,3,2-Diazaphosphinine Toward Propargyl-Phosphine Derivatives and Activated Alkenes 329
many unidentified compounds. Suspecting that the
spectroscopy indicated that two isomers (a and b)
are formed. Compounds 14a (δ (toluene) = 24.80
ppm) and 14b (δ (toluene) = 24.30 ppm) were formed
in a 9:1 ratio and 15a (δ (toluene) = 41.90 ppm) and
15b (δ (toluene) = 46.50 ppm) in a 5:1 ratio. Un-
fortunately, compounds 13–15 were found to be too
oxygen-sensitive to be purified by conventional chro-
matographic separation. Therefore, they were sulfu-
rized prior to purification. Sulfides 16–18 were iso-
lated as colorless solids and fully characterized by
conventional NMR techniques, mass spectrometry,
and elemental analyses.
oxygen sensitivity of the diphenylphosphino group
could be responsible for of this failure, we investi-
gated the sulfurization of 11. Disulfide 12 was eas-
ily synthesized by reacting 11 with elemental sul-
fur in toluene at 50◦C for 16 h. On the basis of 31P
NMR chemical shifts, we propose that the compound
11 features a diphenylphosphinosulfide group and
a free dihydro-1,3,2-diazaphosphabarrelene. Indeed,
the sulfurization of phosphorus atom of the barre-
lene subunit is evidenced by a characteristic down-
field shift (δ (CDCl3) = 50.50 ppm) as observed in
10. Disulfide 12 was successfully characterized by
NMR techniques, mass spectroscopy, and elemen-
tal analyses. The presence of the exocyclic double
bond was easily evidenced by a characteristic signal
1
at δ (CDCl3) = 7.81 ppm in the H NMR spectrum.
This signal appears as a characteristic AMX spin sys-
tem with two important coupling constants with the
two P atoms (2 JHP = 27.70 Hz, 3 JHP = 20.18 Hz) and
a small (4 JHH = 2.49 Hz) coupling constant with the
hydrogen located on the saturated bridge.
Despite many attempts, isomers of 17 and 18
could not be separated by chromatography on silica
gel. Fortunately, crystallization using a mixture of
dichloromethane and methanol afforded the major
isomers 17a and 18a as microcrystals. Their formu-
lation was unambiguously ascribed by combination
of 31P NMR spectroscopy and X-ray crystallography.
Only the structure of 18a is reported here. An ORTEP
view of one molecule of 18a is presented in Fig. 2 and
relevant bond distances and angles are also listed. As
can be seen, the cyano group is located on the C7 car-
bon atom at the ꢃ-position of phosphorus. This is in
good agreement with a theoretical study, that showed
that the outcome of these cycloadditions depends on
the polarity of the two partners [8]. Accordingly, in
many examples, it was shown that the carbon atom
that bears the more attractive functional group is re-
giospecifically grafted at the ꢃ-position at phospho-
rus in the C2 position.
In conclusion, we have showed that a diaza-
phosphinine such as 1 reacts with propargyl phos-
phines in an unusual way to yield the correspond-
ing 7,8-dihydrobarrelenes with an exocyclic double
bond. A theoretical study aimed at understanding
the factors that govern this surprising reactivity is
currently underway in our laboratories. This find-
ing also prompted us to investigate a more ratio-
nale approach to such structures by using the reac-
tivity of these diazaphosphinines toward activated
alkenes. Various polyfunctional structures can now
be anticipated by varying the substitution scheme of
It is still difficult to rationalize why the isomer-
ization of the internal double bond takes place in
these reactions. We first supposed that the transfer of
the sulfur atom, from the phosphine to the P atom of
barrelene, could prevent the retrocycloaddition pro-
cess. However, the synthesis of 11, in which the sul-
fur atom has not been displaced, demonstrates that
the transfer of the sulfur atom is not a prerequisite
to the (1,3)-shift of hydrogen. One may propose that
the displacement of this sulfur atom occurs in a sec-
ond step as the result of the difference of basicity
between the two P atoms.
Beyond this, the synthesis of dihydrophos-
phabarrelene derivatives is interesting and, to the
best of our knowledge, this type of backbone is still
unknown. Supposing that diazaphosphinine could
undergo cycloaddition with activated alkenes, we
explored the reactivity of 1 toward ethyl acrylate,
dimethyl fumarate, and acrylonitrile. In all cases, cy-
cloadditions took place in toluene (between 60 and
75◦C) to afford the corresponding diazaphosphabar-
relenes 13–15. In the synthesis of 14 and 15, the
cycloaddition was not regioselective and 31P NMR

330 Maigrot et al.
the “Service d’analyses du CNRS,” at Gif sur Yvette,
France.
2,5-Diphenyl-1-(3-phenyl-prop-2-ynyl)-
1H-phosphole (2)
To a solution of the 2,5-diphenylphospholide anion
(4.7 mmol) in THF (25 ml) was added 1 equiv. of
3-bromo-1-phenyl-propyne (915 mg, 4.7 mmol). The
reaction mixture was stirred for 15 min at 50◦C and
checked by 31P NMR. After addition of celite, the sol-
vent was evaporated and the coated gel obtained was
deposited onto the top of a silica gel packed-column
for chromatography and eluted with a mixture of
hexane and toluene (70/30). After the evaporation of
solvents the product was obtained as a yellow pow-
der (690 mg, 42%). 31P NMR (CDCl3): δ 4.45. 1H NMR
FIGURE 2 ORTEP drawing of one molecule of 18a (50%
ellipsoid probability). Hydrogen atoms are omitted for clarity.
˚
Relevant bond lengths (A) and angles (deg) data: S(1) P(1),
1.9168(6); P(1) N(1), 1.686(1); P(1) N(2), 1.696(1);
P(1) C(5), 1.857(2); N(1) C(1), 1.289(2); N(2) C(3),
1.290(2); N(3) C(6), 1.141(2); C(1) C(2), 1.524(2);
C(2) C(3), 1.522(2); C(2) C(4), 1.570(2); C(4) C(5),
1.549(2); C(5) C(6), 1.464(2); N(1) P(1) N(2), 105.96(7);
N(1) P(1) C(5), 100.30(7); N(2) P(1) C(5), 97.70(7);
N(1) P(1) S(1), 116.10(5); N(2) P(1) S(1), 116.27(5);
C(5) P(1) S(1), 117.79(6); C(1) N(1) P(1), 113.0(1);
C(3) N(2) P(1), 112.9(1); N(1) C(1) C(2), 119.1(2);
C(3) C(2) C(1), 110.1(1); C(3) C(2) C(4), 106.0(1);
C(1) C(2) C(4), 106.6(1); N(2) C(3) C(2), 119.0(1);
C(5) C(4) C(2), 111.2(1); C(6) C(5) C(4), 112.7(1);
C(6) C(5) P(1), 111.2(1); C(4) C(5) P(1), 107.7(1);
N(3) C(6) C(5), 178.9(2).
2
(CDCl3): δ 2.80 (d, 2H, JHP = 2.0 Hz, CH2), 6.90–
7.50 (m, 17H, CH of C6H5 and H of phosphole). 13C
NMR (CDCl3): δ 16.60 (s, CH2), 77.60 (s, C C6H5),
83.50 (d, 2 JPC = 18.0 Hz, C CH2P), 125.0–140.0 (m,
C6H5), 136.80 (d, 1 JPC = 17.15 Hz, Cꢃ of phosphole),
151.20 (d, 2 JPC = 5.0 Hz, CH of phosphole). MS m/z:
350 (M+). Anal. Calcd for C25H19P: C, 85.69; H, 5.47.
Found: C, 85.55; H, 5.40.
Diphenyl-(3-phenyl-prop-2-ynyl)-phosphine (3)
Lithium (18.5 mmol, 130 mg) was added to a solu-
tion of chlorodiphenyl phosphine (7.5 mmol, 1.65 g)
in THF at room temperature. After 2 h, a control
by 31P NMR indicated the end of the reaction. The
solution was canulated into a solution of 3-chloro-
1-phenyl-propyne (7.5 mmol, 1.10 g) in THF (10 ml)
at −78◦C. After addition, the mixture was allowed to
warm slowly to room temperature and the progress
of the reaction was monitored by 31P NMR. After
evaporation of the solvent, hexane (50 ml) was added
and the resulting solution was filtered. Phosphine
3 was recovered as a colorless oxygen-sensitive oil
(1.35 g, 60%). 31P NMR (CDCl3): δ −13.10. MS m/z:
300 (M+).
the alkene moiety and the substitution scheme of the
phosphinine ring.
EXPERIMENTAL
All reactions were routinely performed under an in-
ert atmosphere of argon or nitrogen by using Schlenk
and glove-box techniques and dry, deoxygenated
solvents. Dry THF and hexanes were obtained by
distillation from Na/benzophenone and dry CH2Cl2
and CDCl3 from P2O5. Dry CD2Cl2 was distilled and
˚
stored, like CDCl3, on 4 A Linde molecular sieves.
NMR spectra were recorded on a Bruker Avance 300
spectrometer operating at 300 MHz for 1H, 75.5 MHz
for 13C, and 121.5 MHz for 31P NMR. Solvent peaks
are used as internal reference relative to Me4Si for 1H
and 13C chemical shifts (ppm); 31P chemical shifts are
relative to a 85% H3PO4 external reference and cou-
pling constants are expressed in hertz. The following
abbreviations are used: b, broad; s, singlet; d, dou-
blet; t, triplet; m, multiplet; p, pentuplet; sext, sex-
tuplet; sept, septuplet; v, virtual. Mass spectra were
obtained at 70 eV with an HP 5989B spectrometer
coupled to an HP 5980 chromatograph by the direct
inlet method. Elemental analyses were performed by
2-[(2,5-Diphenylphospholyl)methyl]-3-phenyl-
6-trimethylsilylphosphinine (6) and
3-[(2,5-Diphenylphospholyl)methyl]-2-phenyl-
6-trimethylsilylphosphinine (7)
A solution of diazaphosphinine 1 (1.26 mmol) in
toluene (16 ml) was heated with phosphole 2 at 110◦C
for 40 h. A control by 31P NMR spectroscopy indi-
cated the formation of monoazaphosphinines 4 and
5. Monoazaphosphinines 4 and 5, which are reactive
intermediates, were characterized by their 31P NMR
chemical shift exclusively. For 4: 31P NMR (toluene):

Reactivity of a 1,3,2-Diazaphosphinine Toward Propargyl-Phosphine Derivatives and Activated Alkenes 331
3
2
δ 273.90 (d, AB system, JPP = 18.30, azaphosphi-
1H NMR (CDCl3): δ 3.55 (d, 2H, JHP = 15.25 Hz,
nine) and –0.25 (d, phosphole); for 5: 31P NMR
(toluene): δ 265.50 (s, azaphosphinine) and −1.10
(s, phosphole). Trimethylsilylacetylene (7 mmol, 0.7
g) was then added and the resulting mixture was
heated at 90◦C for 17 h. After addition of celite, the
solvent was evaporated and the coated gel obtained
was deposited onto the top of a silica gel packed-
column for chromatography. Elution with a mixture
of hexane and toluene (60/40) yielded a fraction con-
taining 6 and 7. After evaporation of hexane, 6 and
7 were recovered as a yellow viscous oil (250 mg,
40%). For 6: 31P NMR (CDCl3): δ 237.70 (d, AB sys-
CH2), 7.01–8.00 (m, 15H, CH of C6H5). 13C NMR
1
(CDCl3): δ 29.40 (d, JPC = 54.30 Hz, CH2), 81.70 (d,
2 JPC = 12.9 Hz, C2), 86.20 (d, JPC = 8.7 Hz, C3),
3
128.0–135.0 (m, C6H5). MS m/z: 332 (M+). Anal.
Calcd for C21H17PS: C, 75.88; H, 5.15. Found: C,
75.70; H, 5.37.
7-[(2,5-Diphenyl-phosphole)-methylen]-
7,8-dihydro-1,3-diaza-2-phosphabarrelene
Sulfide (10)
To a solution of diazaphosphinine 1 (0.8 mmol)
in toluene (10 ml) was added 1 equiv. of alkyne 8
(0.8 mmol, 306 mg) and the resulting mixture was
warmed at 110◦C for 17 h. When the reaction was
completed, celite (1 g) was added and the solvent
was evaporated. The powder obtained was deposited
onto the top of a silica gel packed-column for chro-
matography and eluted with dichloromethane. The
product was recovered as a yellow powder (200 mg,
42%). 31P NMR (C6D6): δ −15.05 (d, 3 JPP = 23.3 Hz, P
phosphole), 50.15 (d, 3 JPP = 23.3 Hz, P S). 1H NMR
(C6D6): δ 0.49 (s, 9H, CH3), δ 0.87 (s, 9H, CH3), 3.62
3
tem, JPP = 20.64, phosphinine) and 0.24 (d, phosp-
1
hole). H NMR (CDCl3): δ 0.13 (s, 9H, SiMe3), 3.40
3
(d, 2H, JHP = 16.85 Hz, CH2), 6.85–7.70 (m, 19H,
H of C6H5, phosphole and phosphinine). For 7: 31P
NMR (CDCl3): δ 229.45 (s, phosphinine) and −0.46 (s,
phosphole). 1H NMR (CDCl3): δ 0.25 (s, 9H, SiMe3),
3
3.00 (s, 2H, JHP = 16.85 Hz, CH2), 6.85–7.70 (m,
19H, H of C6H5, phosphole and phosphinine). MS
m/z: 492 (M+).
2,5-Diphenyl-1-(3ꢁ-phenyl-prop-2ꢁ-ynyl)-
1H-phosphole Sulfide (8)
4
3
(m, 1H, H8), 4.77 (ABX, 1H, JHP = 3.18 Hz, JHH
=
4.9 Hz, H5), 6.89–7.29 (m, 17H, CH of C6H5 and CH
2
S8 (0.35 mmol, 90 mg) was added to a solution of
2 (1.86 mmol , 650 mg) in THF( 10 ml). The reac-
tion was stirred at 80◦C for 2 h. After evaporation of
the solvent, celite was added and the coated silica gel
was then deposited onto the top of a silica gel packed-
column for chromatography. Elution was carried out
with dichloromethane. After evaporation of the sol-
vent, the product was recovered as a yellow viscous
oil (476 mg, 67%). 31P NMR (CDCl3): δ 51.25. 1H NMR
of phosphole), 7.75 (ddd, 1H, JHP = 25.6 Hz,3 JHP
=
18.06 Hz, JHH = 2.24 Hz, CH P). 13C NMR (C6D6):
4
3
δ 27.96 (s, CH3), δ 28.12 (s, CH3), 42.40 (d, JPC
=
15.5 Hz, CMe3), 45.66 (m, C P and C8), 54.00 (d,
3 JPC = 62.7 Hz, C5), 54.11 (m, C7), 127–149 (m, C6H5
1
and Cꢄ of phosphole), 145.52 (d, JCP = 9.1 Hz, Cꢃ
1
of phosphole), 147.00 (d, JCP = 8.9 Hz, Cꢃ of phos-
2
phole), 192.04 (d, JCP = 15.3 Hz, C4), 192.04 (d,
2 JCP = 15.2 Hz, C6). MS m/z: 592 (M+). Anal. Calcd
for C36H38N2P2S: C, 72.95; H, 6.46. Found: C, 73.09;
H, 6.69.
2
(CDCl3): δ 3.30 (d, 2H, JHP = 15.05 Hz, CH2), 6.90–
7.75 (m, 17H, CH of C6H5 and H of phosphole). 13C
NMR (CDCl3): δ 27.60 (d, 1 JPC = 43.9 Hz, CH2), 79.70
2
3
ꢁ
(d, JPC = 13.2 Hz, C2 ), 85.20 (d, JPC = 8.8 Hz,
7-[(Diphenylphosphine sulfide)-methylen]-
7,8-dihydro-1,3-diaza-2-phosphabarrelene
Sulfide (12)
ꢁ
C3 ), 125.0–140.0 (m, C6H5), 137.70 (s, Cꢃ of phosp-
hole), 139.30 (s, CH of phosphole). MS m/z: 382 (M+).
Anal. Calcd for C25H19PS: C, 78.51; H, 5.01. Found:
C, 78.45; H, 5.12.
Alkyne 9 (1.0 mmol, 332 mg) was added to a solu-
tion of diazaphosphinine 1 (1.0 mmol) in toluene (10
ml). The resulting solution was warmed at 80◦C for
3 h. After checking the formation of compound 11,
S8 (0.31 mmol, 80 mg) was added and the mixture
was stirred at 50◦C for 16 h. Celite (1 g) was added
and the solvent was evaporated. The solid obtained
was deposited onto the top of a silica gel packed-
column for chromatography and eluted with a mix-
ture of dichloromethane and methanol (1/10). The
product was recovered as yellow needles (310 mg,
Diphenyl-(3-phenyl-prop-2-ynyl)-phosphine
Sulfide (9)
S8 was added to a solution of 3 (4.33 mmol, 1.30 g) in
toluene (10 ml) and the resulting mixture was heated
at 80◦C for 1 h. After addition of celite (1 g), the pow-
der obtained was deposited onto the top of a silica gel
packed-column for chromatography and eluted with
a mixture of pentane and toluene (75/25).After evap-
oration of solvents the product was obtained as a yel-
low powder (0.935 g, 65%). 31P NMR (CDCl3): δ 40.45.
3
54%).31P NMR (CDCl3): δ 29.55 (d, JPP = 56.18 Hz,
P phosphine), 50.54 (d, 3 JPP = 56.18 Hz, P2). 1H NMR

332 Maigrot et al.
(CDCl3): δ 0.60 (s, 9H, CH3), δ 1.27 (s, 9H, CH3),
4.83 (m, 1H, H8), 5.16 (AMX, 1H, H5), 6.82–7.53
Compounds 17a and 17b were recovered as white
solids (129 mg, 38%). Compound 17a was obtained
as a white solid after crystallization in a mixture of
dichloromethane–methanol (1/1). Data of only 17a,
which was obtained in a pure form, are given. Com-
pound 17a: 31P NMR (CDCl3): δ 25.70. 1H NMR
(CDCl3): δ 1.14 (s, 9H, CH3), δ 1.18 (s, 9H, CH3),
1.25 (m, 4H, H8 and Me), 1.64 (m, 1H, H8), 2.64 (m,
1H, H7), 4.09 (q, 2H, 3 JHC = 6.7 Hz, OCH2), 5.13 (m,
1H, H5). 13C NMR (CDCl3): δ 14.87 (s, Me), 23.71
(s, C8), 28.23 (s, CH3), δ 28.37 (s, CH3), 41.99 (b
2
(m, 15H, C6H5), 7.82 (ddd, 1H, JHP = 27.70 Hz,
4
3 JHP = 20.18 Hz, JHH = 2.49 Hz, CH P). 13C NMR
(CDCl3): δ 26.44 (s, CH3), δ 27.31 (s, CH3), 40.95 (d,
3 JPC = 14.9 Hz, CMe3), 41.15–41.96 (m, C7, C8, and
3
C P), 52.96 (d, JPC = 63.7 Hz, C5), 126.61–150.35
2
(m, C6H5), 192.98 (d, JCP = 15.6 Hz, C4), 196.14 (d,
2 JCP = 15.6 Hz, C6). MS m/z: 574 (M+). Anal. Calcd
for C32H36N2P2S2: C, 66.87; H, 6.31. Found: C, 67.10;
H, 6.63.
1
s, CMe3), 42.59 (d, JPC = 13.69 Hz, C7), 45.26 (d,
3 JPC = 29.23 Hz, C5), 61.89 (s, OCH2), 171.89 (d,
7,8-(Methylcarboxylate)-7,8-dihydro-
1,3-diaza-2-phosphabarrelene Sulfide (16)
2
3 JPC = 12.75 Hz, C O), 194.24 (d, JCP = 18.07 Hz,
2
C4), 194.82 (d, JCP = 16.95 Hz, C6). MS m/z: 342
To a solution of diazaphosphinine (1.0 mmol) in
toluene (10 ml) was added 1.8 equiv. of methyl fu-
marate (1.8 mmol, 260 mg). The resulting mixture
was warmed at 75◦C for 20 h. When the reaction
completed, S8 (0.38 mmol, 97 mg) was added and
the mixture was stirred at 70◦C for 3 h. Celite (1 g)
was added and the solvent was evaporated. The
solid obtained was deposited onto the top of a silica
gel packed-column for chromatography and eluted
with a mixture of dichloromethane and ethyl ac-
etate (80/20). The product was recovered as a white
powder (127 mg, 33%). 31P NMR (CDCl3): δ 46.00.
(M+). Anal. Calcd for C16H27N2O2PS: C, 56.12; H,
7.95. Found: C, 56.45; H, 7.79.
7-Cyano-7,8-dihydro-1,3-diaza-2-
phosphabarrelene Sulfide (18a) and
8-Cyano-7,8-dihydro-1,3-diaza-
2-phosphabarrelene Sulfide (18b)
Acrylonitrile (3.0 mmol, 159 mg) was added to a so-
lution of diazaphosphinine 1 (1.0 mmol) in toluene
(10 ml). The resulting mixture was heated at 65◦C for
2 h. When the reaction completed, S8 (0.38 mmol,
97 mg) was added and the mixture was stirred at
60◦C for 2 h. Celite (1 g) was added and the solvent
was evaporated. The solid obtained was purified by
chromatography and eluted with ethyl acetate. The
mixture of 18a and 18b was recovered as a white
powder (115 mg, 39%). Compound 18a was obtained
in a pure form after crystallization in a mixture of
dichloromethane–methanol (1/1). Data of only 18a
are reported. Compound 18a: 31P NMR (CD2Cl2): δ
1H NMR (CDCl3): δ 1.10 (s, 9H, CH3), δ 1.28 (s,
2
9H, CH3), 3.07 (m, 1H, H8), 3.36 (dd, 1H, JHP
=
16.20 Hz,3 JHH = 6.11 Hz, H7), 3.68 (s, 3H, OMe), 3.74
(s, 3H, OMe), 5.23 (dd, 1H, JHP = 8.82 Hz,3 JHH
=
4
1.80 Hz, H5). 13C NMR (CDCl3): δ 26.10 (s, CH3), δ
26.23 (s, CH3), 40.8 (d, 3 JPC = 15.4 Hz, CMe3), 41.34
3
3
(d, JPC = 15.2 Hz, CMe3), 42.71 (d, JPC = 70.5 Hz,
2
1
C5), 46.05 (d, JPC = 45.10 Hz, C8), 46.60 (d, JPC
=
5.2 Hz, C7), 52.03 (s, OMe), 52.16 (s, OMe), 166.51
(d, 2 JPC = 4.3 Hz, CO C7), 168.17 (d, 3 JPC = 6.61 Hz,
1
42.50. H NMR (CD2Cl2): δ 1.02 (s, 9H, CH3), δ 1.07
2
CO C8), 194.63 (d, JCP = 15.84 Hz, C6), 194.82 (d,
(s, 9H, CH3), 1.62 (m, 1H, H8), 1.96 (m, 1H, H8), 2.75
2 JCP = 15.09 Hz, C4). MS m/z: 386 (M+). Anal. Calcd
for C17H27N2O4PS: C, 52.84; H, 7.04. Found: C, 53.01;
H, 7.42.
(m, 1H, H7), 4.82 (m, 1H, H5). 13C NMR (CD2Cl2):
2
δ 26.91 (s, CH3), δ 27.05 (s, CH3), 29.61 (d, JPC
=
1
51.69 Hz, C8), 32.64 (d, JPC = 6.12 Hz, C7), 42.06
3
3
(d, JPC = 72.21 Hz, C5), 42.61 (d, JPC = 16.1 Hz,
3
CMe3), 42.70 (d, JPC = 15.5 Hz, CMe3), 116.32 (d,
7-(Ethylcarboxylate)-7,8-dihydro-1,3-diaza-
2-phosphabarrelene Sulfide (17a) and
8-(Ethylcarboxylate)-7,8-dihydro-1,3-diaza-
2-phosphabarrelene Sulfide (17b)
3 JPC = 14.5 Hz, C N), 197.60 (d, 2 JCP = 19.25 Hz, C4),
197.86 (d, JCP = 19.21 Hz, C6). MS m/z: 295 (M+).
2
Anal. Calcd for C14H22N3PS: C, 56.93; H, 7.51. Found:
C, 57.09; H, 7.72.
Ethyl acrylate (2.40 mmol, 240 mg) was added to
a solution of diazaphosphinine 1 (1.0 mmol) in
toluene (10 ml). The resulting mixture was heated
at 60◦C for 1 h. When the reaction completed, S8
(0.31 mmol, 80 mg) was added and the mixture was
stirred at 60◦C for 15 h. The crude product was pu-
rified by chromatography and eluted with a solu-
tion of dichloromethane and ethyl acetate (90/10).
X-ray Crystallographic Studies
Single crystals of compounds 10 and18a suitable
for X-ray crystallography were obtained by diffus-
ing methanol into a dichloromethane solution of the
compounds at room temperature in a 5-mm NMR
tube. Data were collected at 150 K on a Nonius Kappa

Reactivity of a 1,3,2-Diazaphosphinine Toward Propargyl-Phosphine Derivatives and Activated Alkenes 333
TABLE 1 Crystal Data and Structural Refinement Details for Structures of Compounds 10 and 18a
10
C36H38N2P2S
18a
Empirical formula
Formula weight
Crystal system
Space group
C14H22N3PS
295.38
Monoclinic
P21/c
9.9570(10)
9.5630(10)
17.3020(10)
105.5060(10)
1587.5(2)
4
592.68
Monoclinic
P21/c
21.0309(3)
15.46550(10)
19.8127(2)
95.308(5)
6416.51(12)
8
˚
a (A)
˚
b (A)
˚
c (A)
β (deg)
3
˚
V (A )
Z
Dcalcd (g/cm3)
1.227
1.236
0.296
µ (cm−1
)
0.228
h, k, l ranges
−27 27; −20 20; −25 25
−13 14; −13 11; −24 24
Crystal size (mm3)
0.22 × 0.22 × 0.18
Lemon yellow plate
27.48
0.20 × 0.20 × 0.12
Colorless plate
30.02
Crystal color and habit
2ꢀ
(deg)
max
No. of reflections measured
No. of independent reflections
No. of reflections used
R 1a[I > 2σ(I )]
28061
14675
11924
0.0409
0.1189
1.045
8149
4635
3358
0.0443
0.1394
1.097
wR 2b[I > 2σ(I )]
Goodness of fit on F2
−3
˚
Largest diff. peak (eA
)
2.058 (0.056)/−0.331 (0.056)
0.730 (0.090)/−0.431 (0.090)
a R1 = ꢁ|F0| − |Fc||/ꢁ|F0|.
2
2
bwR 2 = (ꢁw||F0| − |Fc|| /ꢁw|F0| )1/2
.
˚
[2] Avarvari, N.; Me´zailles, N.; Ricard, L.; Le Floch, P.;
Mathey, F. Science 1998, 289, 1587.
CCD diffractometer using an Mo Kꢃ (ꢂ = 0.71069 A)
X-ray source and a graphite monochromator. Ex-
perimental details are described in Table 1. The
crystal structures were solved using SIR 97 [9] and
SHELXL-97 [10]. ORTEP drawings were made using
ORTEP III for Windows [11].
[3] (a) Me´zailles, N.; Mathey, F.; Le Floch, P. In Progress
in Inorganic Chemistry; Karlin, K. D. (Ed.); Wiley:
New York, 2001; Vol. 49, p. 455; (b) Le Floch, P.
In Phosphorus–Carbon Heterocyclic Chemistry: The
Rise of a New Domain; Mathey, F. (Ed.); Pergamon:
New York, 2001; p. 485.
[4] (a) Doux, M.; Me´zailles, N.; Melaimi, M.; Ricard, L.;
Le Floch, P. Chem Commun 2002, 1566; (b) Doux, M.;
Bouet, C.; Me´zailles, N.; Le Floch, P. Organometallics
2002, 21, 2785.
[5] Gilman, H.; Young, R. V. J Am Chem Soc 1934, 56,
1415.
[6] De Lauzon, G.; Charrier, C.; Bonnard, H.; Mathey, F.
Tetrahedron Lett 1982, 23, 511.
[7] Chen, T. R.; Anderson, O. G. J Org Chem 1987, 52,
1231.
SUPPLEMENTARY DATA
CCDC 198870 (compound 10) and CCDC 198871
(compound 18a) contain the supplementary crys-
tallographic data for this paper. These data can be
obtained free of charge via www.ccdc.cam.ac.uk/
const/retrieving.html (or from Cambridge Crystallo-
graphic Data Centre, 12, Union Road, Cambridge
CB2 1EZ, UK; fax: +44 336033; or deposit@ccdc.
cam.ac.uk).
[8] Frison, G.; Sevin, A.; Avarvari, N.; Mathey, F.; Le
Floch, P. J Org Chem 1999, 64, 5524.
[9] Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano,
G.; Giacovazzo, C.; Guagliardi, A.; Moliterni, A. G. G.;
Polidori, G.; Spagna, R. SIR97, an integrated package
of computer programs for the solution and refine-
ment of crystal structures using single crystal data,
1999.
[10] Sheldrick, G. M. SHELXL-97; Universita¨t Go¨ttingen,
Germany, 1998.
[11] Farrugia, L. J. J Appl Crystallogr 1997, 30, 565–567.
REFERENCES
[1] (a) Le Floch, P.; Carmichael, D.; Ricard, L.; Mathey,
F. J Am Chem Soc 1993, 115, 10665; (b) Waschbu¨sch,
K.; Le Floch, P.; Mathey, F. Organometallics 1996, 15,
1597; (c) Avarvari, N.; Le Floch, P.; Ricard, L.; Mathey,
F. Organometallics 1997, 16, 4089.