An easy one-pot procedure for the synthesis of N-sulfonyl phosphorous ylides and sulfonyl iminophosphoranes

Article abstract of DOI:10.1007/s00706-007-0640-3

Reaction of triphenylphosphine and an electron deficient acetylenic ester in the presence of strong N-H acid such as alkyl and aryl sulfamides or acetamide produces phosphorous ylides at room temperature in CH ₂Cl₂. The aryl sulfamide phosphoranes undergo a smooth transformation reaction in boiling toluene and produce iminophosphoranes. Springer-Verlag 2007.

Full text of DOI:10.1007/s00706-007-0640-3

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Monatshefte fu¨r Chemie 138, 553–557 (2007)
DOI 10.1007/s00706-007-0640-3
Printed in The Netherlands
An Easy One-Pot Procedure for the Synthesis of N-Sulfonyl
Phosphorous Ylides and Sulfonyl Iminophosphoranes
ꢀ
Ahmad Shaabani , Abbas Rahmati, and Soheila Naderi
Department of Chemistry, Shahid Beheshti University, Tehran, Iran
Received October 14, 2006; accepted (revised) December 3, 2006; published online April 17, 2007
# Springer-Verlag 2007
Summary. Reaction of triphenylphosphine and an electron
The successful attack by nucleophilic trivalent
deficient acetylenic ester in the presence of strong N–H acid
such as alkyl and aryl sulfamides or acetamide produces phos-
phorous ylides at room temperature in CH2Cl2. The aryl sulfa-
mide phosphoranes undergo a smooth transformation reaction
in boiling toluene and produce iminophosphoranes.
phosphines on a carbon atom is facilitated when the
latter is conjugated with a carbonyl group, or when it
is part of an unsaturated bond activated otherwise
[9–17]. There have been many studies on reactions
between trivalent phosphorus nucleophiles and ꢀ,ꢁ-
unsaturated carbonyl compounds in the presence of a
proton source such as an alcohol, phenol, or a CH-
acid [9, 17, 18].
During the course of our studies on the develop-
ment of new multicomponent reactions [19, 20] we
investigated the reaction of triphenylphosphine (1)
and dialkyl acetylenedicarboxylate 2 in the presence
of alkyl and aryl sulfamides 3a–3c or acetamide 3d
(Scheme 1).
Keywords. Iminophosphorane; N-Sulfonyl phosphorous
ylides; Aza-Wittig reaction.
Introduction
The iminophosphoranes (phosphazenes, phosphine-
imines, phosphazo compounds), which are elec-
tronically related to phosphorous are important
intermediates in the synthesis of organic compounds
[1, 2]. The iminophosphoranes have been synthe-
sized via two major routes: (i) The Staudinger reac-
tion using tertiary phosphines with organic azides [3]
and (ii) the Kirsanov reaction constituting an imina-
tion of phosphorous pentachloride and its deriva-
tives with compounds containing amino groups [4].
The availability of functionalized iminophosphoranes
has been largely expanded through the synthesis of
nitrogen heterocycles by intramolecular and inter-
molecular Aza-Wittig reactions. In recent years num-
erous research papers and several review articles
have appeared describing the varied use of iminopho-
sphoranes as powerful tools in organic synthesis strat-
egies directed towards the construction of nitrogen
containing hetrocycles [5–8].
Results and Discussion
The novel three component condensation reaction
shown in Scheme 1 produces the stable phosphorous
ylides 4a–4g in excellent yields in CH2Cl2 at room
temperature without using any catalyst and activator.
The structures of 4a–4g were deduced from their
1
high-field H, 13C, and 31P NMR and IR spectral
data. The nature of these compounds as 1:1:1 adducts
were apparent from their mass spectra, which dis-
played the corresponding molecular ion peaks. The
1H, 13C, and 31P NMR spectra of ylides 4a–4g are
consistent with the presence of two isomers. Selected
major and minor diastereomers of 4a–4g are shown
in Scheme 2. The ylide moiety of these compounds is
ꢀ
Corresponding author. E-mail: a-shaabani@cc.sbu.ac.ir

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554
A. Shaabani et al.
Scheme 1
Scheme 2
1
strongly conjugated with the adjacent carbonyl
group and rotation about the partial double bond in
(E)-4 and (Z)-4 is slow on the NMR time scale at
ambient temperature (see Scheme 2).
signments of the H, 13C, and 31P resonances in the
1H, 13C, and 31P NMR spectra of 5a and 5b are given
in the exp. part.
It is important to note that the aryl sulfamides
4a–4d undergo a smooth transformation in boil-
ing toluene and produce iminophosphoranes 5
(Scheme 4, path A); However, methyl sulfamides
4e and 4f and acetamide derivative 4g did not react
under the above mentioned conditions. Thus, the re-
actions of 1, 2, and aryl sulfamide were carried out
under reflux conditions in toluene and directly pro-
duced 5 (Scheme 4, path B).
In conclusion, we introduced a new three-com-
ponent condensation reaction of triphenylphosphine
and dialkyl acetylenedicarboxylates in the presence
of alkyl and aryl sulfamides or acetamide for the
synthesis of a novel family of stable phosphorous
On the basis of the well established chemistry of
trivalent phosphorus nucleophiles, it is reasonable
to assume that phosphorus ylide 4 results from the
initial addition of 1 to 2 and subsequent protonation of
the 1:1 adduct by the NH-acid 3. Then, the Michael
acceptor is attacked by the nitrogen atom of the con-
jugate base of the NH-acid to form phosphorane 4.
Phosphorus ylides 4a–4g undergo a clean reaction in
boiling toluene to produce iminophosphoranes 5 and
dimethyl fumarate or dimethyl maleate (Scheme 3).
Structures of iminophosphoranes 5a and 5b were
assigned to the isolated products on the basis of
1
their IR, H, 13C, 31P, and mass spectra. Partial as-

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Synthesis of N-Sulfonyl Phosphorous Ylides and Sulfonyl Iminophosphoranes
555
Scheme 3
Scheme 4
ylide systems. The one-pot nature protocol in the
absence of catalyst makes it an interesting approach.
In addition, although the present synthesis of imi-
nophosphorans follows the older methods it offers
significant advantages for the synthesis of imino-
phosphoranes from sulfonamides and their ylides.

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556
A. Shaabani et al.
2
1
(OCH3), 56.70 (d, JPC ¼ 17.4Hz, CH–N), 126.12 (d, JPC
¼
Experimental
92.6Hz, P–Cipso), 128.96 (d, JPC ¼ 12.4 Hz, Cortho), 132.47
2
(Cpara), 133.88 (d, JPC ¼ 9.9 Hz, Cmeta), 170.40 (d, JPC
¼
3
2
Melting points were measured on an Electrothermal 9100 ap-
paratus. Mass spectra were recorded on a FINNIGAN-MAT
8430 mass spectrometer operating at an ionization potential of
70eV. IR spectra were recorded on a Shimadzu IR-470 spec-
12.7Hz, CO), 173.69 (d, JPC ¼ 8.5 Hz, CO) ppm; 31P NMR:
3
ꢃ ¼ 22.27 ppm.
1
Minor isomer: 31.5%; H NMR: ꢃ ¼ 2.86 (s, OCH3), 3.13
1
trometer. H, 13C, and 31P NMR spectra were recorded on a
3
(s, CH3SO2), 3.54 (s, OCH3), 4.10 (dd, JHH ¼ 9.1 Hz, and
3JHP ¼ 16.9Hz, P–C–CH), 5.66 (bd, JHH ¼ 9.1 Hz, NH),
3
BRUKER DRX-300 AVANCE spectrometer at 300.13, 75.47,
and 121.48MHz. NMR spectra were obtained on solutions
in DMSO-d6. All the products are known compounds (except
7.48–7.69 (m, 3C6H5) ppm; 13C NMR: ꢃ ¼ 43.34 (CH3SO2),
1
44.68 (d, JPC ¼ 136.2Hz, P¼C), 50.36 (OCH3), 52.52
1
4e–4g), which were characterized by IR, H, 13C, and 31P
2
1
(OCH3), 56.07 (d, JPC ¼ 17.4Hz, CH–N), 125.64 (d, JPC
¼
92.8Hz, P–Cipso), 129.02 (d, JPC ¼ 12.1 Hz, Cortho), 132.13
2
NMR spectral data and their mps compared with literature
[21, 22].
(Cpara), 133.91 (d, JPC ¼ 5.4 Hz, Cmeta), 170.03 (d, JPC
¼
3
2
18.0Hz, CO), 173.83 (d, JPC ¼ 12.1Hz, CO) ppm; 31P
3
NMR: ꢃ ¼ 23.30ppm.
Dimethyl 2-(p-methylsulfonamido)-3-(triphenylphosphoran-
ylidene)butandioate (4a)
To a magnetically stirred solution of 0.262 g 1 (1 mmol) and
0.171 g p-toluenesolfonamide (1 mmol) in 20 cm3 CH2Cl2
was added dropwise a mixture of 0.142 g dimethyl ace-
tylenedicarboxylate (1 mmol) in 2 cm3 CH2Cl2 at room tem-
perature over 10 min. The reaction mixture was stirred for
5 h at room temperature. After completion of the reaction
the solvent was removed under reduced pressure and the
residual solid recrystallized from 1:1 acetone:n-hexane.
Yield 0.495 g (86%); major isomer: 61.8%, minor isomer:
38.2%; pale yellow powder, mp 163–164ꢁC (Ref. [21]
166–167ꢁC).
Diethyl 2-(methylsulfonamido)-3-(triphenylphosphoranylid-
ene)butandioate (4f, C27H30NO6PS)
Yield 0.437 g (83%); white powder, mp 167–169ꢁC; IR
(KBr): ꢂꢀ¼ 3445, 3045, 2900, 1733, 1607, 1473, 1435cmꢂ1
;
MS: m=z (%) ¼ 454 (25), 408 (30), 303 (20), 262 (30), 183
(80), 99 (100).
Major isomer: 74.1%; 1H NMR: ꢃ ¼ 0.83 (t, 3JHH ¼ 7.1 Hz,
3
CH3), 1.16 (t, JHH ¼ 7.2 Hz, CH3), 1.61 (s, CH), 2.84 (s,
3
CH3SO2), 3.63 (t, JHH ¼ 7.1 Hz, CH2), 3.95–4.14 (m, CH2),
6.29 (d, 3JHH ¼ 9.1 Hz, NH), 7.41–7.66 (m, 3C6H5) ppm; 13
C
¼
1
NMR: ꢃ ¼ 14.12 (CH3), 14.21 (CH3), 42.48 (d, JPC
2
61.6Hz, P¼C), 43.30 (CH3SO2), 56.57 (d, JPC ¼ 17.5Hz,
1
CHN), 61.35 (OCH2), 61.44 (OCH2), 126.22 (d, JPC
Diethyl 2-(p-methylsulfonamido)-3-(triphenylphosphoranyl-
idene)butandioate (4b)
¼
2
91.5Hz, Cipso), 128.53 (d, JPC ¼ 12.2Hz, C), 128.82 (d,
3
2JPC ¼ 12.3 Hz, C), 131.97 (C), 132.10 (d, JPC ¼ 10.0 Hz,
Yield 0.549 g (91%); major isomer: 59.9%, minor iso-
mer: 40.1%; pale yellow powder, mp 167–168ꢁC (Ref.
[21] 168–169ꢁC).
2
C), 133.65 (C), 133.85 (d, JPC ¼ 10.0 Hz, C), 165.65 (C),
2
3
169.85 (d, JPC ¼ 13.1Hz, CO), 173.07 (d, JPC ¼ 8.4 Hz,
CO) ppm; 31P NMR: ꢃ ¼ 22.21 ppm.
Minor isomer: 25.9%; 1H NMR: ꢃ ¼ 1.13 (t, 3JHH ¼ 6.8 Hz,
Dimethyl 2-(benzensulfonamido)-3-(triphenylphosphoranyl-
idene)butandioate (4c)
3
CH3), 1.21 (t, JHH ¼ 7.1 Hz, CH3), 2.11 (s, CH), 2.81 (s,
CH3SO2), 3.91–4.18 (m, 2CH2), 5.57 (d, 3JHH ¼ 8.6 Hz, NH),
Yield 0.488 g (87%); major isomer: 68.2%, minor isomer:
31.8%; pale yellow powder, mp 150–153ꢁC (Ref. [21] 161–
162ꢁC).
7.41–7.70 (m, 3C6H5) ppm; 13C NMR: ꢃ ¼ 13.91 (CH3),
1
14.03 (CH3), 42.13 (CH3SO2), 44.18 (d, JPC ¼ 61.9Hz,
2
P¼C), 56.09 (d, JPC ¼ 17.2Hz, CHN), 61.27 (OCH2), 61.51
1
2
(OCH2), 125.71 (d, JPC ¼ 92.0Hz, Cipso), 128.72 (d, JPC
¼
12.4Hz, Cortho), 128.72 (d, JPC ¼ 12.0 Hz, Cortho), 131.72
2
Diethyl 2-(benzensulfonamido)-3-(triphenylphosphoranylid-
ene)butandioate (4d)
(Cpara), 132.27 (d, JPC ¼ 2.9 Hz, Cmeta), 133.10 (C), 165.32
3
(C), 169.64 (d, 2JPC ¼ 18.7 Hz, CO), 173.07 (d, 3JPC ¼ 8.3 Hz,
Yield 0.548 g (93%); major isomer: 71.9%, minor isomer:
28.1%; pale yellow powder, mp 163–165ꢁC (Ref. [21] 158–
159ꢁC).
CO) ppm; 31P NMR: ꢃ ¼ 23.21 ppm.
Diethyl 2-(methylsulfonamido)-3-(triphenylphosphoranylid-
ene)butandioate (4g, C26H26NO5P)
Dimethyl 2-(methylsulfonamido)-3-(triphenylphosphoranylid-
ene)butandioate (4e, C25H26NO6PS)
Yield 0.338g (73%); white powder, mp 160–163ꢁC; IR (KBr):
ꢂꢀ¼ 3420, 2948, 1741, 1668, 1482, 1432cmꢂ1; MS: m=z
(%) ¼ 404 (80), 372 (30), 303 (50), 287 (75), 262 (100), 183
(80), 165 (20).
Yield 0.404 g (81%); pale yellow powder, mp 163–164ꢁC; IR
(KBr): ꢂꢀ¼ 3315, 2940, 1744, 1611, 1480, 1429 cmꢂ1; MS:
m=z (%) ¼ 354 (15), 340 (30), 277 (15), 201 (25), 183 (70),
152 (30), 122 (50), 51 (100).
1
Major isomer: 61.5%; H NMR: ꢃ ¼ 1.97 (s, CH3CONH),
1
3
3
Major isomer: 68.5%; H NMR: ꢃ ¼ 2.88 (s, OCH3), 3.13
3.15 (s, OCH3), 3.70 (dd, JPH ¼ 15.2Hz, JHH ¼ 8.9 Hz,
3
3
(s, CH3SO2), 3.71 (s, OCH3), 4.04 (dd, JHH ¼ 9.1Hz, and
CHN), 6.27 (d, JHH ¼ 8.8 Hz, NH), 7.47–7.73 (m, 3C6H5)
3
2
3JHP ¼ 7.78 Hz, P–C–CH), 6.35 (bd, JHH ¼ 9.1 Hz, NH),
ppm; 13C NMR: ꢃ ¼ 49.05 (OCH3), 51.54 (d, JPC ¼ 17.8Hz,
1
7.48–7.69 (m, 3C6H5) ppm; 13C NMR: ꢃ ¼ 42.20 (CH3SO2),
Hz, CHN), 52.29 (OCH3), 126.53 (d, JPC ¼ 91.9Hz, Cipso),
1
43.91 (d, JPC ¼ 127.6 Hz, P¼C), 49.41 (OCH3), 52.53
128.62 (d, 2JPC ¼ 12.3Hz, P–Cortho), 133.80 (d, 3JPC ¼ 9.8 Hz,