Reactivity of lithium diphenylphosphonium diylides towards phosphorus electrophiles: Synthesis of α,β-unsaturated phosphorus compounds

Article abstract of DOI:10.1016/S0022-328X(01)00670-2

The study of the reactivity of non-stabilized, semi-stabilized and stabilized lithium diphenylphosphonium diylides 1-4 towards Ph₂PCl, allowed the synthesis of various α,β-unsaturated phosphines 13-14, via the intermediate formation of the corresponding functionalized monoylides 9-10 and their in situ reaction with carbonyl compounds. In many cases, the reaction is Z-stereoselective and the created double bond can be di- or also trisubstituted. The precise ¹H-NMR study of the phosphines 13a-d and the X-ray analysis of 13a (Z isomer) allowed us to assign without ambiguity the stereochemistry of these compounds and to solve a ¹H-NMR question. Contrary to reported results in the literature for 13a, we have shown that for the double bond of this phosphine, there is no exception to the general rule ³J_HH(trans) > ³J_HH(cis). The extension of this reactivity study to other phosphorus electrophiles such as Ph₂P(O)Cl, Ph₂P(S)Cl and (EtO)₂P(O)Cl allowed, as preliminary results, the E-stereoselective synthesis of styrylphosphine oxide and sulfide and diethyl styrylphosphonate.

Full text of DOI:10.1016/S0022-328X(01)00670-2

Journal of Organometallic Chemistry 624 (2001) 307–315
www.elsevier.nl/locate/jorganchem
Reactivity of lithium diphenylphosphonium diylides towards
phosphorus electrophiles: Synthesis of a,b-unsaturated phosphorus
compounds
Marc Taillefer* 1, Henri Jean Cristau* 2, Alain Fruchier, Virginie Vicente
Laboratoire de Chimie Organique, ENSCM, UMR 5076 du CNRS, 8 rue de l’Ecole Normale, 34296 Montpellier, Cedex 5 France
Received 3 November 2000; accepted 22 December 2000
Dedicated to Professor Jean F. Normant on the occasion of his 65th birthday
Abstract
The study of the reactivity of non-stabilized, semi-stabilized and stabilized lithium diphenylphosphonium diylides 1–4 towards
Ph2PCl, allowed the synthesis of various a,b-unsaturated phosphines 13–14, via the intermediate formation of the corresponding
functionalized monoylides 9–10 and their in situ reaction with carbonyl compounds. In many cases, the reaction is Z-stereoselec-
1
tive and the created double bond can be di- or also trisubstituted. The precise H-NMR study of the phosphines 13a–d and the
X-ray analysis of 13a (Z isomer) allowed us to assign without ambiguity the stereochemistry of these compounds and to solve a
1H-NMR question. Contrary to reported results in the literature for 13a, we have shown that for the double bond of this
3
phosphine, there is no exception to the general rule JHH(trans)\3JHH(cis). The extension of this reactivity study to other
phosphorus electrophiles such as Ph2P(O)Cl, Ph2P(S)Cl and (EtO)2P(O)Cl allowed, as preliminary results, the E-stereoselective
synthesis of styrylphosphine oxide and sulfide and diethyl styrylphosphonate. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Phosphonium diylide; Metallated ylide; Wittig reaction; a,b-Unsaturated phosphine; Phosphine X-ray structure; 1H-NMR
(sulfoxides, amides, esters, acids, amidines, phosphines),
the double bond being di- or trisubstituted [4]. Re-
cently, in a preliminary note we have shown that the
non-stabilized and unsubstituted lithium diylide 1
(RꢀH) reacts with phosphorus electrophiles such as
Ph2PCl, Ph2P(O)Cl and Ph2P(S)Cl, allowing the synthe-
sis of the styrylphosphine and the corresponding oxide
and sulfide [4e].
1. Introduction
Lithium phosphonium diylides, whose first example
was discovered by G. Wittig in 1949 [1], were until the
recent past mainly studied as ligands in coordination
chemistry [2]. In order to test the potential of these
compounds in synthesis, we have developed a general
synthetic route to their direct precursors, the di-
alkylphosphonium salts [3], thus allowing an easy ac-
cess to all types of diylides whatever their non-stabilized
(1, 2), semi-stabilized (3) or stabilized (4) character
(Scheme 1). We have then studied the reactivity of these
diylides, and shown that these reagents thanks to a
strong nucleophilic character, are excellent tools in
organic synthesis. Indeed, they offer a general method
for the synthesis of various a,b-unsaturated compounds
We report here more general results dealing with the
study of the reactivity of various types of diylides (1–4)
regardless of their stabilization degree, towards phos-
phorus electrophiles. A general method for the synthe-
sis of a,b-unsaturated phosphines as well as other
phosphorus compounds has been developed. In addi-
tion, this article deals with an NMR question concern-
ing an apparent peculiarity of the styrylphosphine 13a
3
for which it has been reported that the JHH corre-
1 * Corresponding author. Tel.: +33-4-67144352; Fax: +33-4-
67144319; e-mail: taillefe@cit.enscm.fr.
sponding to the double bond is larger for the Z isomer
than for the E one. In fact, this apparent inversion does
not exist, as we will demonstrate in this article.
2 * Corresponding author: Tel.: +33-4-67144352; Fax: +33-4-
67144319; e-mail: cristau@cit.enscm.fr.
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00670-2

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M. Taillefer et al. / Journal of Organometallic Chemistry 624 (2001) 307–315
2. Results
18a (entry 9) is obtained as the main product of the
reaction. The expected trisubstituted vinylic phosphine
14a is also generated, but in a low yield around 10%.
However, using the activated p-nitrobenzaldehyde, the
corresponding trisubstituted a,b-unsaturated phosphine
14c is synthesized in an acceptable yield (entry 10). The
corresponding alkene 18c was not obtained in this case.
The configuration of the created double bond of
13–14 corresponds to a Wittig reaction from reactive
monoylides 9 and 10 of non-stabilized type (the carban-
ion is substituted by H or Me and by Ph2P, which are
not electron-withdrawing substituents). This type of
ylides normally affords predominantly Z-alkenes, al-
though the reaction conditions may have an important
effect on the stereochemistry [5]. Indeed, in most cases,
the major a,b-unsaturated phosphine formed is the Z
one, although a ratio Z/E of about 50/50 has been
observed for the 2-pyridylcarboxaldehyde (with 1: entry
4) and for the nitrobenzaldehyde (with 2: entry 10).
The semi-stabilized 3 (R=Ph) and stabilized 4 (R=
COPh) diylides, react also quantitatively with the
diphenylchlorophosphine, but only the corresponding
alkene 19a (E/Z: 75/25) and 20a (E/Z: 90/10) are
generated in the reaction mixture (yields: 65–70%),
using in the second addition step benzaldehyde as car-
bonyl compound (entries 11 and 12).
The results presented here are based on the proposed
sequence below (Scheme 1). In a first step, phospho-
nium diylides 1–4 in the presence of a phosphorus
electrophile such as diphenylchlorophosphine, lead via
a
nucleophilic substitution to the formation of
monoylides 5–8 which are transformed instanta-
neously, via an intramolecular prototropy, into the
functionalized monoylides 9–12. In a second step, the
in situ addition of a carbonyl compound, mainly an
aldehyde, allows the formation of the corresponding
a,b-unsaturated phosphines 13–16, by a Wittig reac-
2
tion. The formations of 9–12 (two doublets: JPP cou-
pling constant), of the two possible isomers (E and/or
Z) of the vinylphosphines 13–16, as well as of
Ph2P(O)CH2R (resulting from a Wittig reaction), are
monitored by 31P-NMR.
Starting from a non-stabilized and non-substituted
diylide 1 (RꢀH) and in presence of aromatic, heteroaro-
matic or enolisable aldehydes, the synthesis of the
corresponding a,b-unsaturated phosphines 13a–f is per-
formed in very good yields (Table 1: entries 1–6). This
one pot synthetic method proceeds in very mild condi-
tions (addition of Ph2PCl and of the aldehyde at 20°C),
the two reactions with the phosphorus electrophile and
then with aldehyde being instantaneous. However, in
the presence of phenylcyclohexanone, the carbonyl
compound reacts only with the intermediate monoylide
5, affording the (4-methylenecyclohex-1-yl)benzene 17h
(Table 1; entry 8).
The method allows then the one pot synthesis, usu-
ally Z stereoselective, of various a,b-unsaturated phos-
phines. The yields are good and the double bond can be
di- or trisubstituted. This method is interesting in com-
parison with those of the literature which present some
disadvantages. The limitations encountered, are for ex-
ample low yields and oxidation problems [6], the neces-
sity to work in presence of AIBN or under UV
Starting from a non-stabilised and substituted diylide
2 (R=Me), the first step with Ph2PCl proceeds very
quickly but, in presence of benzaldehyde, the alkene
Scheme 1. Synthesis of a,b-unsaturated phosphines 13–16.

M. Taillefer et al. / Journal of Organometallic Chemistry 624 (2001) 307–315
309
Table 1
Synthesis of a,b-unsaturated phosphines 13–16 and alkenes 17–20
3
3
irradiation [7], isomerisation problems for the product
[8] or even the preliminary isolation of diphosphorus
precursors (in this last case, only melting points and
micro-analyses are given for the identification of the
phosphines [9]).
the observed JHH(cis) and JHH(trans), in every case
assigned to the real isomers, respectively Z and E.
Indeed, in the literature this assignment is based on
synthetic methods. For example in the case of 13a the
identification is based on the reaction of Ph2PCl with
the Grignard reagent of E and Z bromostyrene, which
afforded a mixture of the styrylphosphine E and Z
isomers [10]. This identification method being in our
opinion not totally unambiguous, we have, still in the
case of 13a, confirmed the correct assignment by reduc-
ing the PꢀS bond of the well identified E isomer of the
corresponding styrylphosphine sulfide 28a (Scheme 2).
However, a total inversion of configuration during the
reduction, although unlikely, being not wholly ex-
cluded, we have definitively resolve the question of the
correct identification of the isomers Z and E, by a
Concerning the styryl phosphine 13a, it has been
reported in the literature [10,11] that for this phosphine,
3
and another one with R=propyl, JHH(trans) could be
3
less than JHH(cis). However this unique result to our
knowledge, is not clearly linked to the geometry of the
molecule, no apparent inversion being established when
R is a methyl or a tert-butyl group. Additionally the
two numerical values attributed to the coupling con-
stants of 13a (10.8 and 12.8 Hz) were too small to
3
correspond to JHH(trans). Confronted to these results,
a doubt was present for the phosphines 13–14: Were

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M. Taillefer et al. / Journal of Organometallic Chemistry 624 (2001) 307–315
Scheme 2.
1
Fig. 1. H-NMR parameters of the Z and E ethylenic phosphines 13d (R%R¦CO : C5H4NꢁCHO) and 13c (R%R¦CO : O2NꢁC6H4ꢁCHO) in CDCl3.
1
reinvestigation of the H-NMR spectra of some phos-
are straightforward and show that the signal of H-6 is
correlated with the high-frequency olefinic hydrogen in
the Z isomer and with the low-frequency one in the E
isomer. Similar long-range correlations are observed in
13c where the AA’XX’ system of the p-nitrophenyl
group is obviously identified in 2D spectra. The results
are collected in Fig. 1.
phines 13–14.
1
The comparison of the H-NMR spectra of four of
our phosphines, 13a–d allowed us to assign without
ambiguity the chemical shifts and coupling constants of
the three spin system given by the two hydrogens of the
double bond and the phosphorus atom of their Z and E
isomers.
Among these four compounds, 13c and 13d present
the most easily analysed spectra: the three nuclei form
an AMX spin system in which DwAM is so large that
one-half of the AM part is located under or very close
to the large signals of the P(phenyl)2 group. gs-COSY
experiments using a high digital resolution (0.2 Hz/pt)
allow the detection of the hidden signal with a good
precision and identify at the same time which signal
belongs to the hydrogen close to the pyridyl group in
13d: the analyses of the 4-spin system of the pyridine
Fig. 2. 1H-NMR parameters of Z and E ethylenic phosphines 13b
(R%R¦CO : MeꢁC6H4ꢁCHO) in CDCl3.

M. Taillefer et al. / Journal of Organometallic Chemistry 624 (2001) 307–315
311
Fig. 3. 1H-NMR parameters of Z and E ethylenic phosphines 13a (R%R¦CO: PhCHO) in [2H]6-acetone/CDCl3 80/20.
Fig. 4. (top) 1H-NMR spectrum of the E isomer of 13a in CDCl3. (bottom) 1H NMR spectrum of the E isomer of 13a in a mixture 80/20 of
[2H]6-acetone and CDCl3.
Compounds 13a and 13b differ from the preceding
ones in the sense that the signals of the aryl groups
coming from the carbonyl compounds (phenyl and
p-methylphenyl respectively), are strongly mixed with
those of the P(phenyl)2 groups, keeping off any detec-
tion of long-range correlations with one hydrogen of
the double-bond. However, chemical shifts and cou-
pling constants of the Z isomers leave no doubt about
the assignments if they are compared to 13c and 13d
(Figs. 2 and 3). The same holds for the E isomer of 13b,
even if the two signals of the olefinic hydrogens are very
close and require the 3-spin system to be analysed as
ABX to obtain the coupling constants (Fig. 2).
The spectrum of the E isomer of 13a in CDCl3 shows
a simple doublet at 6.984 ppm with a splitting of 11 Hz
(Fig. 4(top)) already described first by Aguiar in 1966
[6] then by Duncan [10] and Mitchell [11]. Actually, this
doublet is due to a degeneracy of the ABX system
where DwAB is close to zero and the observed splitting is
not a coupling constant. By addition of successive
amounts of [2H]6-acetone to the CDCl3 solution, the
anisochrony of the two hydrogens is increased, leading
the eight transitions of the AB part to appear (Fig.
4(bottom)) and allowing the calculation of the chemical
shifts and coupling constants reported in Fig. 3.
Our results, besides the fact that they prove the

312
M. Taillefer et al. / Journal of Organometallic Chemistry 624 (2001) 307–315
identification of the isomers of the phosphines 13,
indicate then that for 13a, the apparent inversion in the
coupling constants was the result of an inadequate
carbonyl compound. The postulated mechanism is of
the same type as described for the synthesis of the
phosphines 13–16. The yields are good and the reaction
is E-stereoselective, according to the stabilized charac-
ter of the intermediate monoylide 24–26, substituted by
the electron-withdrawing group Ph2P(S), Ph2P(O) or
(EtO)2P(O) [5]. Work is in progress to generalise, as for
Ph2PCl, the synthesis to other a,b-unsaturated phos-
phorus compounds, by variation of the carbonyl
substrate.
1
interpretation of the H-NMR spectra.
Thus, the four phosphines we studied do not present
3
any exception to the rule JHH(trans)\3JHH(cis), and
3
this classic rule applies also for JPH. Another point to
2
notice is the large JPH in E isomers compared to the Z
ones, a point which disagrees with the results quoted by
Mitchell [11].
Additionally, in the case of 13a, we checked the
correct isomeric assignment from a crystal of the corre-
sponding postulated Z isomer [mp=89°C: l 31P= −
24.2 (THF)] and confirmed this configuration by X-Ray
analysis (Fig. 5 and Table 2).
A preliminary study of the reactivity of 1 has also
allowed the synthesis of the oxides 27a and sulfides 28a
corresponding to the styrylphosphine 13a, as well as the
synthesis of the diethyl styrylphosphonate 29a, using
respectively Ph2P(O)Cl, Ph2P(S)Cl and (EtO)2P(O)Cl as
phosphorus electrophiles and the benzaldehyde as a
3. Conclusions
The study of the reactivity of non-stabilized, semi-
stabilized and stabilized lithium diphenylphosphonium
diylides 1–4 towards Ph2PCl, Ph2P(O)Cl, Ph2P(S)Cl
and (EtO)2P(O)Cl, allowed us to develop, in the case of
non-stabilized diylides, a general and one-pot synthetic
method to synthesize various a,b-unsaturated phospho-
rus compounds (phosphines 13–14, phosphine oxide
27a, phosphine sulfide 28a, phosphonate 29a), via the
intermediate formation of the corresponding function-
alized monoylides 9–10 or 24–26 and their in situ
reaction with carbonyl compounds. Depending on the
stabilisation degree of the intermediate monoylide the
reaction is Z or E stereoselective and the created double
bond can be di- or trisubstituted. Additionally, we have
shown that for the double bond of phosphines 13, the
3
classic rule JHH(trans)\3JHH(cis) is still valid. These
results show once again the interest of diylides 1–4 as
synthetic tools. Further developments will be under-
taken in order to enlarge the field of application of this
reaction with the synthesis of other a,b-unsaturated
phosphorus compounds, as for example the butadienyl
phosphines and analogues.
Fig. 5. Molecular structure of the Z isomer of 13a.
Table 2
,
Selected bond distances (A) and bond angles (°) with e.s.d.s. in
parentheses for 13a
4. Experimental
Bonds lengths
C(2)ꢁC(211)
C(1)ꢁC(2)
P(1)ꢁC(121)
P(1)ꢁC(111)
P(1)ꢁC(1)
Melting points were determined using a Wild Leitz
1.467(2)
1.339(2)
1.8385(14)
1.8412(15)
1.8140(16)
1
350 and are given uncorrected. H and 31P-NMR spec-
tra were recorded on a Bruker AC-200 spectrometer at
1
200.1 MHz and 81.0 MHz respectively. H-2D experi-
ments were performed on a Bruker DRX-250 with a
1
Bond angles
z-gradients unit. H and 31P chemical shifts are in ppm
from TMS and external 85% H3PO4 respectively. 31P
quantitative measurements on reaction mixtures (THF)
were made using a relaxation delay of 20 sec with no
1H irradiation and an external [2H]6-DMSO lock. The
program gNMR was used for the calculations of 1H
spectra [12]. IR spectra were obtained with a Perkin–
Elmer 377. Mass spectra were measured with a Jeol
JMS DX-300 spectrometer. All solvents were distilled
from drying agents prior to use. Tetrahydrofuran
(THF) was distilled under nitrogen atmosphere over
C(1)ꢁP(1)ꢁC(111)
C(1)ꢁP(1)ꢁC(121)
C(111)ꢁP(1)ꢁC(121)
P(1)ꢁC(1)ꢁC(2)
C(1)ꢁC(2)ꢁC(211)
P(1)ꢁC(111)ꢁC(112)
P(1)ꢁC(111)ꢁC(116)
P(1)ꢁC(121)ꢁC(122)
P(1)ꢁC(121)ꢁC(126)
C(2)ꢁC(211)ꢁC(212)
C(2)ꢁC(211)ꢁC(216)
102.77(7)
99.78(7)
98.57(6)
130.62(12)
131.14(15)
125.28(11)
115.93(12)
122.09(12)
119.01(12)
117.76(14)
124.34(14)

M. Taillefer et al. / Journal of Organometallic Chemistry 624 (2001) 307–315
313
Table 3
Synthesis of vinylic phosphorus compounds 27a–29a
a
Entry
Time (min)
X
R¦
27a–29a
27a–29a l 31P (THF)
d
d
e
FR b (%)
Yield c (%)
E
Z
E/Z
g
1
2
3
1
O
S
O
Ph
Ph
OEt
27a
28a
29a
100
100
90
86
50
25.47
37.76
19.66
100/0
95/5
100/0
1
29.36
40 f
a Reaction time after addition of the aldehyde. Reaction temperature: 20°C.
b Formation rate determined by 31P-NMR.
c Isolated yield after column chromatography.
d Chemical shifts (ppm) of 27a–29a (E and Z isomers) in the reaction mixture (THF).
e Ratio determined by 31P-NMR.
f Reaction time in hours. Reaction temperature: 65°C.
g The Z isomer has been obtained by the quantitative oxidation of Z-13a with H2O2: l 31P=20.0 ppm.
Table 4
Characterisation of a,b-unsaturated phosphines 13–14 a
Compound
1H NMR (CDCl3) l (ppm), J (Hz)
MS (EI) m/z
13a
Z: 89°C (hexane) Lit.
93–95°C [10]
Z: 102°C (hexane)
Figs 3, 4a, 4b
Fig. 2
288
13b
13c
302
333
Z and E mixture (83/17): Fig. 1
83°C (hexane)
14c
Z and E mixture (50/50): Z isomer: 1.87 (dd, 3JPH=3, 4JHH=1.5, 3 H, CH3) 7.34–7.39 (m, 11 H, 2 C6H5 347
104°C
and ꢀCH) 7.5 (d, 3JHH=8.5, 2 H, C6H4) 8.15 (d 3JHH=8.5, 2 H, C6H4)
E isomer: 2.06 (dd, 3JPH=10, 4JHH=1.4, 3 H, CH3) 6.55 (d, 3JPH=11, 1H,
ꢀCH) 7.34–7.44 (m, 10 H, 2 C6H5) 7.48 (d, 3JHH=8.8, 2 H, C6H4) 8.22 (d
3JHH=8.8, 2 H, C6H4)
13d
13e
Z: 116°C (hexane)
Isomer mixture: oil
Fig. 1
289
Z isomer: 6.31 (dd, 2JPH=1.5, 3JHH=13, 1 H, PꢁCH) 6.37 (dd, 1H, OCHꢀCH) 278
6.55 (d, 1H, OCHꢀCHꢁCH) 7.12 (dd, 3JHH=13, 3JPH=23.7, 1H, HꢁCꢀCꢁP)
7.31–7.50 (m, 11H, 2 C6H5 and OꢁCH)
E isomer: 6.31 (d, 1H, OCHꢀCHꢁCH) 6.41 (dd, 1H, OCHꢀCH) 6.64 (dd,
2JPH=12.4, 3JHH=17, 1 H, PꢁCH) 6.88 (dd, 3JHH=17, 3JPH=9.7, 1H,
HꢁCꢀCꢁP) 7.30–7.48 (m, 11H, 2 C6H5 and OꢁCH)
1.26–1.37 (m, 3H, CH3) 2.59–2.63 (m, 1H, CHꢁMe) 2.84–3.0 (m, 2H, CH2)
5.96–6.82 (m, 2H, CHꢀCH) 7.12–7.84 (m, 15H, ArH)
13f
Isomer mixture: oil
330
a Satisfactory elemental analyses were obtained for the Z pure or the Z/E mixtures of 13 or 14.
sodium/benzophenone and stored over sodium. The
reactions were performed under nitrogen using Schlenk
techniques. n-Butyllithium commercial solutions in hex-
ane (Aldrich) were titrated before use [13]. Commercial
aldehydes and ketones (Aldrich) were used without
– 50°C, a solution of n-BuLi (7 ml of 1.6 M solution in
hexane; 11.2 mmol) is added dropwise. At the end of
the addition, the mixture is allowed to warm up in one
hour to 20°C (yellow solution). The phosphorus elec-
trophile
Ph2PCl,
Ph2P(O)Cl,
Ph2P(S)Cl
or
purification.
Phosphorus
electrophiles,
Ph2PCl,
(EtO)2P(O)Cl (5.6 mmol), is then directly added (with-
out additional solvent) to the solution. After 15 minutes
at 20°C, the carbonyl compound (5.6 mmol) is quickly
and directly added. The reaction times and tempera-
tures, are indicated, depending on the carbonyl com-
pounds, in Tables 1 and 3.
Work-up: At the end of the reaction (monitored by
31P-NMR), the solution is concentrated and the result-
ing oils are dissolved into dichloromethane. After wash-
ing of the organic layer with water (3×50 ml) and
drying over MgSO4, the mixture is filtered and concen-
trated, at a temperature below 25°C. The resulting
Ph2P(O)Cl, Ph2P(S)Cl and (EtO)2P(O)Cl, were distilled
under vacuum and stored under nitrogen prior use.
4.1. Reacti6ity of 1–4 towards Ph2PCl, Ph2P(O)Cl,
Ph2P(S)Cl and (EtO)2P(O)Cl. Synthesis of the h,i-un-
saturated phosphorus compounds 13–14, 27a–29a: Gen-
eral procedure
The diphenyldialkylphosphonium salt corresponding
to the diylide 1–4 [3] (5.6 mmol) is introduced in THF
(200 ml). To the heterogeneous mixture, cooled at

314
M. Taillefer et al. / Journal of Organometallic Chemistry 624 (2001) 307–315
Table 5
,
tion in idealised positions (d(CH)=0.96 A) and their
atomic coordinates were recalculated after each cycle.
They were given isotropic thermal parameters 20%
higher than those of the carbon to which they are
attached. Least-squares refinements were carried out by
minimising the function Sw(ꢀFoꢀ−ꢀFcꢀ), where Fo and Fc
are the observed and calculated structure factors. The
weighting scheme used in the last refinement cycles was
w=w%[1−{DF/6|(Fo)}2]2 where w%=1/S1nArTr(x) with
three coefficients Ar for the Chebyshev polynomial
ArTr(x) where x was Fc/Fc(max) [15].Models reached
convergence with R=S(ꢀꢀFoꢀ−ꢀFcꢀꢀ)/S(ꢀFoꢀ) and Rw=
Crystal data and details of the structure determination for 13a
Formula
C
288.33
20H17
P
Formula weight (g)
Shape (color)
Size (mm)
Crystal system
Space group
Box (colorless)
0.75×0.28×0.12
Monoclinic
P21/c
16.352(3)
5.9197(9)
16.582(4)
109.33(2)
1514.6
4
608
1.264
1.661
,
a (A)
,
b (A)
,
c (A)
i (°)
3
,
V (A )
Z
[Sw(ꢀFoꢀ−ꢀFcꢀ)2/Sw(Fo)2]1/2
, having values listed in
F(000)
z (calc), (g cm−3
)
Table 5.
v (Mo–Ka) (cm−1
)
The calculations were carried out with the CRYSTALS
package programs [16] and the molecular view was
realised with the help of ORTEP [17].
Diffractometer
Stoe IPDS
0.71073
160(2)
Radiation (Mo–Ka) (u)
Temperature (K)
Detector distance (mm)
Scan mode
.
70
€ (rotation)
0.0B€B199.5
1.5
5. Supplementary material
€ range (°)
€ increment (°)
Exposure time (min)
2q range (°)
Absorption method
Number of reflections collected
Number of unique reflections
Merging factor Rint
Reflections used (I\2|(I))
R
Crystallographic data (excluding structure factors)
for the structure reported in this paper have been
deposited with the Cambridge Crystallographic Data
Centre as supplementary publication no. CCDC
150786. Copies of these data may be obtained free of
charge from The Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK. Fax: +44-1223-336033;
e-mail: deposit@ccdc.cam.ac.uk or www.ccdc.cam.
ac.uk.
3
4.3B2qB52.1
None
11984
2843
0.0394
2075
0.0305
0.0363
Chebyshev
1.28, 0.237, 0.970
0.011
−0.250/0.306
1.070
Rw
Weighting scheme
Coefficient Ar
(D/|)max
Dzmin/Dzmax
GOF
Acknowledgements
Variable parameters
191
We thank N. Beauvais (Maˆıtrise student), D. Car-
pentier and P. Beuchet (Maste`re students) for their
participation to this work.
crude oils are purified by chromatography on alumina
(solvents: hexane–dichloromethane, 90:10) to give the
corresponding a,b-unsaturated phosphorus compounds.
The characterisation of the phosphines 13–14 is pre-
sented Table 1 (31P-NMR), Table 4 (1H-NMR, Mass,
elemental analyses and melting point when available),
in the NMR discussion and in Section 4.2.
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