Preparation and chemistry of phosphoranyl-derived iodanes

Article abstract of DOI:10.1021/jo026604y

The preparation and chemistry of novel phosphoranyl-derived λ³-iodanes is reported. The phosphoranyl-derived phenyliodonium sulfonates were prepared in good yields by the reaction of stabilized phosphonium ylides [1-triphenylphosphoranylidene-2-propanone, methyl(triphenylphosphoranylidene)acetate, (triphenylphosphoranylidene)acetaldehyde, and (triphenylphosphoranylidene)acetonitrile] with the pyridinium complex of iodobenzene ditriflate or with [hydroxy(tosyloxy)-iodo]benzene under mild conditions. These compounds represent a potentially useful class of reagents that combine in one molecule synthetic advantages of a phosphonium ylide and an iodonium salt. Specifically, phosphorane-derived phenyliodonium tosylates can react with soft nucleophiles, such as iodide, bromide, benzenesulfinate, and thiophenolate anions, with a selective formation of the respective α-functionalized phosphonium ylides, which can be further converted to alkenes by the Wittig reaction with benzaldehyde. The phosphoranyl-derived benziodoxoles can be prepared by the reaction of 1-acetoxybenziodoxole with stabilized phosphonium ylides. An unusual ligand exchange on the iodine(III) center resulting in the substitution of a carbon ligand with an oxygen ligand was observed in the reaction of these compounds with strong acids.

Full text of DOI:10.1021/jo026604y

P r ep a r a tion a n d Ch em istr y of P h osp h or a n yl-Der ived Iod a n es
Viktor V. Zhdankin,†,* Olena Maydanovych,† J on Herschbach,† J essica Bruno,†
Elena D. Matveeva,‡ and Nikolai S. Zefirov‡
Department of Chemistry, University of Minnesota Duluth, Duluth, Minnesota 55812, and Department of
Chemistry, Moscow State University, Moscow, 119899, Russia
vzhdanki@d.umn.edu
Received October 24, 2002
The preparation and chemistry of novel phosphoranyl-derived λ3-iodanes is reported. The phos-
phoranyl-derived phenyliodonium sulfonates were prepared in good yields by the reaction of
stabilized phosphonium ylides [1-triphenylphosphoranylidene-2-propanone, methyl(triphenylphos-
phoranylidene)acetate, (triphenylphosphoranylidene)acetaldehyde, and (triphenylphosphoranylide-
ne)acetonitrile] with the pyridinium complex of iodobenzene ditriflate or with [hydroxy(tosyloxy)-
iodo]benzene under mild conditions. These compounds represent a potentially useful class of reagents
that combine in one molecule synthetic advantages of a phosphonium ylide and an iodonium salt.
Specifically, phosphorane-derived phenyliodonium tosylates can react with soft nucleophiles, such
as iodide, bromide, benzenesulfinate, and thiophenolate anions, with a selective formation of the
respective R-functionalized phosphonium ylides, which can be further converted to alkenes by the
Wittig reaction with benzaldehyde. The phosphoranyl-derived benziodoxoles can be prepared by
the reaction of 1-acetoxybenziodoxole with stabilized phosphonium ylides. An unusual ligand
exchange on the iodine(III) center resulting in the substitution of a carbon ligand with an oxygen
ligand was observed in the reaction of these compounds with strong acids.
In tr od u ction
times greater than the triflate.2a Mixed phosphonium-
iodonium ylides, which are best described by the reso-
nance contributors 1a and 1b (Figure 1), represent a
potentially interesting, but underinvestigated, class of λ3-
iodanes combining in one molecule synthetic advantages
of alkenyliodonium salts and phosphonium ylides.
During the past few years the chemistry of hypervalent
iodine compounds (λ3-iodanes) has experienced an un-
precedented growth.1 A broad variety of polyvalent iodine
reagents have been prepared and new, highly useful
synthetic procedures have been developed. Iodonium salts
and ylides represent an especially important class of
iodanes with rich and synthetically useful chemistry.1-3
In particular, alkenyliodonium salts have found synthetic
application as powerful alkenylating reagents in the
reactions with various nucleophiles.1,2a-c The high reac-
tivity of iodonium salts in the reactions with nucleophiles
is generally explained by the “hyperleaving group” prop-
erties of the phenyliodanyl group, which is a remarkably
good nucleofuge with a leaving group ability about 106
The preparation of the tetrafluoroborate derivatives 1
by the reaction of phosphonium ylides with (diacetoxy-
iodo)benzene in the presence of HBF4 was first reported
by Neilands and Vanag in 1964.4 The same authors
described the reaction of compounds 1 with HCl and HBr,
leading to iodobenzene and the corresponding phospho-
nium salt resulting from nucleophilic substitution of PhI
with the halide anion in the protonated molecule of 1.4
More recently, in 1984, Moriarty and co-workers reported
the preparation of several new tetrafluoroborate deriva-
tives 1 and the X-ray crystal structure for one of them.5
Very recently, Huang and coauthors investigated the
tandem reactions of tetrafluoroborates 1 and their arso-
nium analogues with several common nucleophiles and
aldehydes.6 In particular, this work6 provided additional
experimental support toward our earlier evaluation of
mixed phosphonium-iodonium ylides as useful class of
reagents that combine in one molecule synthetic advan-
tages of a phosphonium ylide and an iodonium salt.7
† University of Minnesota Duluth.
‡ Moscow State University.
(1) (a) Varvoglis, A. Hypervalent Iodine in Organic Synthesis;
Academic Press: London, 1997; Varvoglis, A. Tetrahedron 1997, 53,
1179-1255. (b) Stang, P. J .; Zhdankin, V. V. Chem. Rev. 1996, 96,
1123-1178; Zhdankin, V. V.; Stang, P. J . Chem. Rev. 2002, 102, 2523-
2584. (c) Wirth, T.; Hirt, U. H. Synthesis 1999, 1271-1287. (d)
Kirschning, A. Eur. J . Org. Chem. 1998, 11, 2267-2274. (e) Kitamura,
T.; Fujiwara, Y. Org. Prep. Proced. Int. 1997, 29, 409-458. (f) Moriarty,
R. M.; Prakash, O. Org. React. 1999, 54, 273-418.
(2) For recent reviews on iodonium salts see: (a) Ochiai, M. In
Chemistry of Hypervalent Compounds; Akiba, K., Ed.; VCH Publish-
ers: New York, 1999; Chapter 13, pp 359-387; Ochiai, M. J . Orga-
nomet. Chem. 2000, 611, 494-508. (b) Pirkuliev, N. S.; Brel, V. K.;
Zefirov, N. S. Russ. Chem. Rev. 2000, 69, 105-120. (c) Okuyama, T.
Acc. Chem. Res. 2002, 35, 12-18. (d) Zhdankin, V. V.; Stang, P. J .
Tetrahedron 1998, 54, 10927-10966. (e) Grushin, V. V. Chem. Soc.
Rev. 2000, 29, 315-324.
(4) Neilands, O.; Vanag, G. Dokl. Akad. Nauk SSSR 1964, 159, 373.
(5) Moriarty, R. M.; Prakash, I.; Prakash, O.; Freeman, W. A. J .
Am. Chem. Soc. 1984, 106, 6082.
(6) Huang, Z.; Yu, X.; Huang, X. J . Org. Chem. 2002, 67, 8261;
Huang, Z.; Yu, X.; Huang, X. J . Tetrahedron Lett. 2002, 43, 6823.
(7) Zhdankin, V. V.; Maydanovych, O.; Herschbach, J .; Bruno, J .;
Matveeva, E. D.; Zefirov, N. S. Tetrahedron Lett. 2002, 42, 2359.
(3) For recent review on iodonium ylides, see: Neilands, O. Latv.
J . Chem. 2002, 27-59.
10.1021/jo026604y CCC: $25.00 © 2003 American Chemical Society
Published on Web 01/04/2003
1018
J . Org. Chem. 2003, 68, 1018-1023

Phosphoranyl-Derived Iodanes
F IGURE 1. Mixed phosphonium-iodonium tetrafluorobo-
rates.
F IGURE 2. Compound 4a .
SCHEME 1
nium salt and the triflate anion weakly associated with
the iodine atom. The I-C bond distances of 2.068 Å (I-
C1) and 2.108 Å (I-Ph) are within the range of a typical
bond length in diaryliodonium salts (2.0-2.1 Å). The
distance between the iodine atom and the nearest oxygen
of the triflate anion, I‚‚‚OTf, is 2.957 Å, while the shortest
P‚‚‚OTf distance is 4.370 Å, indicating the absence of
secondary bonding between the phosphorus atom and the
triflate anion. The phosphorus atom has a relatively short
intramolecular interaction with the carbonyl oxygen
(P-O ) 2.849 Å). The C1-C2 bond distance of 1.415 Å
indicates a significant double bond character, which is
consistent with the enolic structure of 4a (Figure 2) and
typical of the carbonyl-stabilized phosphonium ylides.
Structure of 4a is in good agreement with the X-ray data
on the related tetrafluoroborate derivative published in
1984 by Moriarty and co-workers.5 Overall, the X-ray
data indicate that the actual structure of mixed phos-
phonium-iodonium ylides is better described by the
resonance contributor 1a , which is similar to alkenyl-
iodonium salts, rather than the contributor 1b, analogous
to iodonium ylides.
In the present work, we report the preparation and
chemistry of two new types of mixed phosphonium-
iodonium ylides, namely, the phosphorane-derived phe-
nyliodonium sulfonates and the phosphorane-derived
benziodoxoles. X-ray crystal structures of these com-
pounds were reported in our preliminary communica-
tions.7,8
Resu lts a n d Discu ssion
P h osp h or a n yl-Der ived P h en yliod on iu m Su lfo-
n a tes. The synthesis of new sulfonate derivatives of
phosphonium-iodonium ylides 4 and 6 is outlined in
Scheme 1. The triflate iodonium derivatives 4 can be
prepared in good yields by the reaction of phosphonium
ylides 2 with the pyridinium complex of iodobenzene
ditriflate (3)9 under mild conditions. It should be empha-
sized that the use of the pyridinium complex 3 is essential
in this procedure; the application of PhIO/Tf2O in the
absence of pyridine leads to the formation of a black tar,
due to the strongly acidic character of this reagent. The
tosylate derivatives 6 can be conveniently prepared under
similar conditions by treatment of phosphonium ylides
2 with Koser reagent10 in dichloromethane (Scheme 1).
Products 4 and 6 in general were isolated in the form of
stable, white, microcrystalline solids, with the exception
of the nitrile derivatives 4c and 6c, which had lower
thermal stability and were isolated as oils.
Sulfonates 4 and 6 were identified by NMR, IR, and
elemental analysis. In particular, proton NMR spectra
of these compounds showed signals of four phenyls as
well as the respective signals of the substituent X and
the tosylate anion for products 6. 13C NMR displayed a
low-intensity signal of the ylidic carbon at 60-30 ppm
as a doublet with J CP ≈ 100 Hz and the signals corre-
sponding to the aromatic rings and the X-groups.
On the basis of these structural data, it could be
anticipated that the chemical reactivity of the sulfonate
derivatives 4 and 6 is similar to the reactivity of alk-
enyliodonium salts and phosphonium ylides. At the same
time, due to the powerful electron-withdrawing ability
of the phenyliodanyl group,1b the nucleophilicity of the
ylidic carbon in these compounds is sharply decreased
and, therefore, their reactivity as phosphonium ylides in
the Wittig reaction with aldehydes should be low. As
expected, we have found that no reaction is observed
between compounds 6 and benzaldehyde, even at tem-
peratures above 100 °C. In contrast, compounds 6 are
highly reactive in the reactions with nucleophiles due to
the excellent leaving group ability of the phenyliodanyl
group. We have found that sulfonates 6 readily react with
halide anions and with benzenesulfinate anion at room
temperature, under the same conditions as previously
reported by Ochiai for alkenyliodonium salts.11,12
Tosyla te 6a reacts with potassium iodide or potassium
bromide in methanol with a selective formation of the
respective R-halogenated phosphonium ylides 7 (Scheme
2), which were isolated as analytically pure microcrys-
talline solids in high yield. Products 7 were identified on
the basis of spectroscopic data and elemental analysis.
Likewise, the reaction of tosylate 6b with sodium ben-
zenesulfinate under mild conditions affords sulfone 8 as
the major product (Scheme 3).
A single-crystal X-ray structure of iodonium triflate 4a
was reported in our preliminary communication.7 The
structural data revealed a typical geometry of an iodo-
(11) (a) Ochiai, M.; Oshima, K.; Masaki, Y. Tetrahedron Lett. 1991,
32, 7711. (b) Ochiai, M.; Oshima, K.; Masaki, Y. J . Am. Chem. Soc.
1991, 113, 7059.
(12) (a) Ochiai, M.; Oshima, K.; Masaki, Y.; Kunishima, M.; Tani,
S. Tetrahedron Lett. 1993, 34, 4829. (b) Ochiai, M.; Kitagawa, Y.;
Toyonari, M.; Uemura, K. Tetrahedron Lett. 1994, 35, 9407.
(8) Zhdankin, V. V.; Maydanovych, O.; Herschbach, J .; Tykwinski,
R. R.; McDonald, R. J . Am. Chem. Soc. 2002, 124, 11614.
(9) Weiss, R.; Seubert, J . Angew. Chem., Int. Ed. Engl. 1994, 33,
891.
(10) Koser, G. F. Aldrichimica Acta 2001, 34, 89.
J . Org. Chem, Vol. 68, No. 3, 2003 1019

Zhdankin et al.
SCHEME 2
SCHEME 3
SCHEME 4
SCHEME 5
cyanide,15d amides,15e and tosylate,15f,g can be prepared
by ligand exchange on iodine upon treatment of 1-hy-
droxy-1,2-benziodoxol-3(1H)-one with the appropriate
nucleophile. These various benziodoxole derivatives have
found practical application as the reagents for oxidative
functionalization of organic substrates.1,14b Considering
the importance of benziodoxole derivatives in organic
chemistry, we decided to explore the preparation and
chemistry of novel phosphoranyl-derived benziodoxoles.
Compounds 12 were prepared by the reaction of
phosphoranes 2 with acetoxybenziodoxole 11 in the
presence of trimethylsilyl triflate and pyridine (Scheme
5) and isolated in the form of stable, white, microcrys-
talline solids.
Benziodoxoles 12 were characterized by elemental
analysis and spectroscopic data. In particular, proton
NMR spectra of these compounds showed signals of the
triphenylphosphonium group and the benziodoxole ring,
as well as the respective signals of the substituent R. 13
C
NMR displayed a low-intensity signal of the ylidic carbon
at 45-26 ppm as a doublet with J CP ≈ 100 Hz and the
signals corresponding to the aromatic rings and the R
groups.
The mechanism of nucleophilic substitution in mixed
ylides 6 is probably similar to the analogous reactions of
alkenyliodonium salts and can be realized by several
alternative pathways, such as an addition-elimination
route, ligand coupling on iodine, or a direct SN2-type
process.11,12 The R-substituted phosphonium ylides that
can be conveniently prepared by the reactions of mixed
ylides 6 with nucleophiles represent an important class
of reagents useful in the synthesis of natural products.13
Mixed ylides 6 cannot react directly with carbonyl
compounds, but their products of nucleophilic substitu-
tion can be easily converted to alkenes 9 by the Wittig
reaction with benzaldehyde. A representative example
of such a tandem reaction is shown in Scheme 4.
Compounds 6a and 6b selectively react with lithium
thiophenolate in dichloromethane to afford the respective
ylide 9 along with iodobenzene as the byproduct. The
subsequent reaction of ylides 9 with benzaldehyde yields
alkenes 10 with a predominant formation of Z isomers.
P h osp h or a n yl-Der ived Ben ziod oxoles. In the past
decade, there has been considerable interest and research
activity focused on the chemistry of five-membered
iodine(III) heterocycles, derivatives of benziodoxole.1,14
The most important and best-investigated heterocyclic
iodane is 1-hydroxy-1,2-benziodoxol-3(1H)-one, the cyclic
tautomer of 2-iodosylbenzoic acid. Other iodine-substi-
tuted benziodoxoles, such as the peroxide,15a,b azide,15c
Single-crystal X-ray structures of both products 12a
and 12b were reported in our preliminary communica-
tion.8 The structural data revealed a typical, essentially
planar geometry of the benziodoxole ring system with the
I-O bond lengths at about 2.5-2.6 Å. The I-C bond
lengths in 12b are 2.056 and 2.134 Å, which are values
comparable to the analogous bonds in derivatives 4a . The
ylidic fragment in 12 has a planar, enolic geometry, with
all parameters similar to 4a (Figure 2); the plane of the
enolate fragment in 12 is perpendicular to the benz-
iodoxole ring system.
It is known from the literature that, in contrast to
iodonium salts, benziodoxole derivatives are generally not
reactive in nucleophilic substitution reactions.1,14b,15 As
(15) (a) Ochiai, M.; Ito, T.; Takahashi, H.; Nakanishi, A.; Toyonari,
M.; Sueda, T.; Goto, S.; Shiro, M. J . Am. Chem. Soc. 1996, 118, 7716;
Sueda, T.; Fukuda, S.; Ochiai, M. Org. Lett. 2001, 3, 2387; Ochiai, M.;
Nakanishi, A.; Ito, T. J . Org. Chem. 1997, 62, 4253; Ochiai, M.;
Kajishima, D.; Sueda, T. Tetrahedron Lett. 1999, 40, 5541; Ochiai, M.;
Kajishima, D.; Sueda, T. Heterocycles 1997, 46, 71; Ochiai, M.;
Nakanishi, A.; Yamada, A. Tetrahedron Lett. 1997, 38, 3927. (b) Dolenc,
D.; Plesnicar, B. J . Am. Chem. Soc. 1997, 119, 2628. (c) Zhdankin, V.
V.; Krasutsky, A. P.; Kuehl, C. J .; Simonsen, A. J .; Woodward, J . K.;
Mismash, B.; Bolz, J . T. J . Am. Chem. Soc. 1996, 118, 5192. (d)
Zhdankin, V. V.; Kuehl, C. J .; Krasutsky, A. P.; Bolz, J . T.; Mismash,
B.; Woodward, J . K.; Simonsen, A. J . Tetrahedron Lett. 1995, 36, 7975;
Zhdankin, V. V.; Kuehl, C. J .; Arif, A. M.; Stang, P. J . Mendeleev
Commun. 1996, 50; Akai, S.; Okuno, T.; Takada, T.; Tohma, H.; Kita,
Y. Heterocycles 1996, 42, 47. (e) Zhdankin, V. V.; McSherry, M.;
Mismash, B.; Bolz, J . T.; Woodward, J . K.; Arbit, R. M.; Erickson, S.
Tetrahedron Lett. 1997, 38, 21. (f) Zhdankin, V. V.; Kuehl, C. J .;
Krasutsky, A. P.; Bolz, J . T.; Simonsen, A. J . J . Org. Chem. 1996, 61,
6547. (g) Muraki, T.; Togo, H.; Yokoyama, M. Synlett 1998, 286;
Muraki, T.; Togo, H.; Yokoyama, M. J . Org. Chem. 1999, 64, 2883.
(13) J ohnson, A. W.; Kaska, W. C.; Starzewsky, K. A. O.; Dixon, D.
Ylides and Imines of Phosphorus; Wiley: New York, 1993.
(14) Reviews on benziodoxoles: (a) Morales-Rojas, H.; Moss, R. A.
Chem. Rev. 2002, 102, 2497. (b) Zhdankin, V. V. Rev. Heteroatom Chem.
1997, 17, 133.
1020 J . Org. Chem., Vol. 68, No. 3, 2003

Phosphoranyl-Derived Iodanes
SCHEME 6
conditions. These compounds represent a potentially
useful class of reagents that combine in one molecule
synthetic advantages of a phosphonium ylide and an
iodonium salt. Specifically, iodonium tosylates 6 can react
with soft nucleophiles, such as iodide, bromide, benze-
nesulfinate, and thiophenolate anions, with a selective
formation of the respective R-functionalized phosphonium
ylides 7-9, which can be further converted to alkenes
10 by the Wittig reaction with benzaldehyde.
The phosphoranyl-derived benziodoxoles 12 can be
prepared by the reaction of acetoxybenziodoxole 11 with
stabilized phosphonium ylides. An unusual ligand ex-
change on the iodine(III) center resulting in the substitu-
tion of a carbon ligand with an oxygen ligand was
observed in the reaction of these compounds with strong
acids.
SCHEME 7
Exp er im en ta l Section
Gen er a l. All reactions were performed under dry nitrogen
atmosphere with flame-dried glassware. All commercial re-
agents were ACS reagent grade and used without further
purification. Methylene chloride and acetonitrile were distilled
from CaH2 immediately prior to use. Diethyl ether was distilled
from Na/benzophenone. Phenyl(dipyridinium)iodonium triflate
3 was prepared from (diacetoxyiodo)benzene, trimethylsilyl
triflate, and pyridine by a known procedure.9 1-Acetoxyben-
ziodoxole 1 was prepared by heating the commercial 2-iodo-
sylbenzoic acid with acetic anhydride.17 Infrared spectra were
recorded as a KBr pellet; NMR spectra were recorded at 300
MHz (1H NMR) and 75.5 MHz (13C NMR). Chemical shifts are
reported in parts per million (ppm). 1H and 13C chemical shifts
are referenced relative to the residual nondeuterated solvent.
Microanalyses were carried out by Atlantic Microlab, Inc.,
Norcross, GA.
Typ ica l P r oced u r e for th e P r ep a r a tion of P h osp h o-
r a n yl-Der ived P h en yliod on iu m Tr ifla tes. 1-P h en yliod o-
n iu m [1-(tr iph en ylph osph or an yliden e)-2-pr opan on e] Tr i-
fla te, 4a . A solution of ylide 2a (0.106 g, 0.335 mmol) in
dichloromethane (3 mL) was added to a suspension of reagent
39 (0.221 g, 0.335 mmol) under a nitrogen atmosphere at room
temperature. The solution was additionally stirred for 3 h,
washed several times with water, dried, and concentrated in
expected, we have found that the chemical properties of
compounds 12 are quite different from the noncyclic
phosphoranyl derivatives 6 and other known iodonium
salts. In contrast to the noncyclic derivatives 6, benz-
iodoxoles 12 are not reactive toward soft nucleophiles,
such as PhS- and I- anions, even at elevated temperature
(up to 100 °C) and in the presence of copper or palladium
catalysts. On the other hand, compounds 12 readily react
with strong acids (e.g., HOTf), affording phosphonium
salt 13 and benziodoxole 14 as major products (Scheme
6). Phosphonium triflate 13 was isolated from the reac-
tion mixture as the major product and identified by
elemental analysis, MS, and NMR spectroscopy. In
1
particular, the H and 13C NMR spectra of triflate 13 are
a
vacuum. Recrystallization of the residue from dichlo-
close to the literature data reported for the similar
romethane/diethyl ether afforded 0.556 g (83%) of product 4a
in the form of a white, microcrystalline solid: mp 108-110
phosphonium halides and tetrafluoroborate.16
1
°C; IR 3065, 1534, 1440, 1252, 512 cm-1; H NMR (CDCl3) δ
This reaction represents an unusual example of a
ligand exchange on the iodine(III) center resulting in the
substitution of a carbon ligand with an oxygen ligand. A
plausible mechanism of this reaction includes protonation
of the ylidic carbon of 12 followed by substitution of the
carbon ligand in intermediate 15 with water (Scheme 7).
This remarkable substitution is most likely explained by
a stabilizing effect of the phosphonium moiety on the
carbon leaving group in the protonated intermediate 15.
7.66-7.27 (m, 20H), 2.62 (s, 3H); 13C NMR (CDCl3) δ 193.4,
133.7, 133.5, 131.3, 130.9, 129.5, 129.3, 123.2 (d, J CP ) 94 Hz),
121.0 (q, J CF ) 318 Hz), 118.1, 43.3 (d, J CP ) 104 Hz), 27.0;
FAB HRMS m/z 521.0504 [M - OTf]+, calcd for C27H23IOP
521.050. Anal. Calcd for C28H23F3IO4PS: C, 50.16; H, 3.46; I,
18.93; S, 4.78. Found: C, 49.72; H, 3.48; I, 19.01; S, 4.65. For
X-ray structure see ref 7.
P h en yliodon iu m [m eth yl(tr iph en ylph osph or an yliden e)-
a ceta te] Tr ifla te, 4b. In a similar procedure, the reaction of
ylide 2b (300 mg, 0.85 mmol) with the generated in situ
reagent 3 (0.85 mmol) afforded 0.519 g (89%) of product 4b:
Con clu sion
mp 131-132 °C; IR 3062, 1598, 1435, 1250, 1115, 500 cm-1
;
1H NMR (CDCl3) δ 7.62-7.26 (m, 20H), 3.56 (s, 3H); 13C NMR
(CDCl3) δ 168.1, 134.1, 133.9, 132.0, 131.1, 129.6, 129.5, 123.5
(d, J CP ) 98 Hz), 121 (q, J CF ) 318 Hz), 118.3, 53.0, 26.7 (d,
J CP ) 98 Hz). Anal. Calcd for C28H23F3IO5PS‚H2O: C, 47.74;
H, 3.58; I, 18.02; S, 4.55. Found: C, 47.55; H, 3.36; I, 18.12; S,
4.51.
In conclusion, we have reported the preparation and
chemistry of novel phosphoranyl-derived λ3-iodanes. The
sulfonate iodonium derivatives 4 and 6 can be prepared
in good yields by the reaction of phosphonium ylides 2
with the pyridinium complex of iodobenzene ditriflate (3)
or with [hydroxy(tosyloxy)iodo]benzene (5) under mild
P h en yliod on iu m [(tr ip h en ylp h osp h or a n ylid en e)a ceto-
n itr ile] Tr ifla te, 4c. The reaction of ylide 2c (300 mg, 0.995
(16) (a) Gray, G. A. J . Am. Chem. Soc. 1973, 95, 7736. (b) Nesmey-
anov, N. A.; Berman, S. T.; Petrovskii, P. V.; Lutsenko, A. I.; Reutov,
O. A. J . Organomet. Chem. 1977, 129, 41.
(17) Baker, G. P.; Mann, F. G.; Sheppard, N.; Tetlow, A. J . J . Chem.
Soc. 1965, 3721.
J . Org. Chem, Vol. 68, No. 3, 2003 1021

Zhdankin et al.
mmol) with reagent 3 (0.995 mmol) under similar conditions
afforded 0.507 g (78%) of product 4c as a colorless oil: IR 3065,
the yellow microcrystalline powder of product 7a (103 mg,
80%): mp 96-98 °C; IR (KBr) 3049, 2991, 1676, 1524, 1362,
1
1
2153, 1440, 1251, 1024, 565 cm-1; H NMR (CDCl3) δ 7.36-
1156, 1102, 995 cm-1; H NMR (CDCl3) δ 7.8-7.3 (m, 15H),
7.77 (m). 13C NMR (CDCl3) δ 137.4, 133.8, 132.3, 132.1, 131.9,
129.6, 129.5, 124.0 (d, J CP ) 100 Hz), 121 (q, J CF ) 318 Hz),
118.3, 117.7, 31.5 (d, J CP ) 100 Hz). Due to the compound’s
low stability, C, H, N analysis was not possible.
2.4 (s, 3H); 13C NMR (CDCl3) δ 190.4, 133.5, 131.9, 128.6, 126.6
(d, J CP ) 92.9 Hz), 28.0, 10.0 (d, J CP ) 115 Hz, CdP); FAB
HRMS m/z (%) 444.0165 (75) M+, 445.0207 (100), [M + H]+;
calcd for C21H18IOP 444.0140; calcd for C21H19IOP 445.0218.
Anal. Calcd for C21H18IOP‚0.5H2O: C, 55.65; H, 4.23. Found:
C, 55.97, H, 4.30.
1-B r o m o -1-(t r ip h e n y lp h o s p h o r a n y lid e n e )-2-p r o -
p a n on e, 7b. In a similar procedure, the reaction of ylide 6a
(200 mg, 0.29 mmol) with potassium bromide (172 mg, 1.4
mmol) in methanol afforded 92 mg (81%) of 7b as a white
microcrystalline powder: mp 136-138 °C; IR 3050, 2981, 1682,
1505, 1377, 1156, 1102, 999 cm-1; 1H NMR (CDCl3) δ 7.8-7.5
(m, 15H), 2.4 (s, 3H); 13C NMR (CDCl3) δ 188.9, 133.6, 132.0,
128.5, 125.9 (d, J CP ) 92.9 Hz), 45.8 (d, J CP ) 117 Hz), 26.5.
FAB HRMS m/z (%) 396.0275 (19), 398.0295 (23), M+; calcd
for C21H1879BrOP 396.0278; calcd for C21H1881BrOP 398.0258.
Anal. Calcd for C21H18BrOP: C, 63.49; H, 4.57; Br, 20.11.
Found: C, 63.41; H, 4.77; Br, 19.83.
P h en yliod on iu m [(tr ip h en ylp h osp h or a n ylid en e)a cet-
a ld eh yd e] Tr ifla te, 4d . The reaction of ylide 2d (200 mg,
0.660 mmol) with reagent 3 (0.660 mmol) under similar
conditions afforded 0.243 g (56%) of product 4d : mp 129-130
°C; IR 3062, 2812, 1735, 1440, 1260, 1029, 500 cm-1; 1H NMR
(CDCl3) δ 9.55 (d, J PH ) 26 Hz, 1H), 7.24-7.96 (m, 20H); 13C
NMR (CD3CN) δ 179.5, 136.1, 135.6, 134.7, 134.2, 133.8, 132.5,
122.7 (d, J CP ) 93 Hz), 121 (q, J CF ) 318 Hz), 116.4, 56.0 (d,
J CP ) 94 Hz). FAB HRMS m/z 507.0363 [M - OTf]+, calcd for
C
26H21IOP 507.040. Anal. Calcd for C27H21F3IO4PS: C, 49.40;
H, 3.22; I, 19.33; S, 4.89. Found: C, 49.54; H, 3.42; I, 19.45; S,
4.95.
Typ ica l P r oced u r e for th e P r ep a r a tion of P h osp h o-
r a n yl-Der ived P h en yliod on iu m Tosyla t es. 1-P h en yl-
iodon iu m [1-(tr iph en ylph osph or an yliden e)-2-pr opan on e]
Tosyla te, 6a . A mixture of reagent 5 (0.196 mg, 0.5 mmol)
and phosphonium ylide 2a (0.151 g, 0.5 mmol) in dry dichlo-
romethane (20 mL) was stirred overnight at room temperature
under nitrogen. The resulting solution was concentrated in a
vacuum, yielding a slightly yellow oil. The oil was recrystal-
lized from dichloromethane and diethyl ester to afford 0.170
g (50%) of product 6a as white crystals: mp 111-112 °C; IR
Ben zen esu lfon yl[m eth yl(tr iph en ylph osph or an yliden e)-
a ceta te], 8. A solution of sodium benzenesulfinate (232 mg,
1.4 mmol) in dimethyl sulfoxide (20 mL) was added to the
solution of compound 6b (200 mg, 0.29 mmol) in dichlo-
romethane (20 mL) under a nitrogen atmosphere at 0 °C. The
resulting mixture was stirred overnight at room temperature.
Then mixture was washed with distilled water (3 × 15 mL),
and the organic layer was dried with sodium sulfate and
concentrated in a vacuum, yielding product 8 as a colorless
oil (82 mg, 62%): IR (CCl4) 3057, 2976, 1738, 1432, 1259, 1190,
1115, 1071 cm-1; 1H NMR (CDCl3) δ 7.9-7.1 (m, 20H), 3.3 (s,
3H); 13C NMR (CDCl3) 168.1, 147.9, 133.6, 132.4, 128.6, 127.8,
127.4, 124.9, 124.5 (d, J CP ) 90.0 Hz), 59.0 (d, J CP ) 112 Hz),
50.3, 29.5; FAB HRMS m/ z 497.09524 [M + Na]+, calcd for
1
3050, 1550, 1223, 1176, 1114, 1031 cm-1; H NMR (CDCl3) δ
7.4-8.0 (m, 20H), 7.34 (d, 2H, J ) 8 Hz), 7.12 (d, 2H, J ) 8
Hz) 2.63 (s, 3H), 2.33 (s, 3H); 13C (CDCl3) δ 193.5, 143.4, 139.1,
135.4, 133.7, 133.4, 131.1, 129.4, 129.3, 128.4, 126.0, 123.6 (d,
J CP ) 92.9 Hz), 118.5, 43.9 (d, J CP ) 102 Hz), 27.3, 21.3. Anal.
Calcd for C34H30IO4PS: C, 58.97; H, 4.37; I, 18.32. Found C,
59.05; H, 4.34; I, 18.45.
C
27H23O4PSNa 497.09658.
1-P h en ylsu lfa n yl-1-(t r ip h en ylp h osp h or a n ylid en e)-2-
P h en yliodon iu m [m eth yl(tr iph en ylph osph or an yliden e)-
a ceta te] Tosyla te, 6b. In a similar procedure, the reaction
of ylide 2b (170 mg, 0.51 mmol) with reagent 5 (200 mg, 0.51
mmol) in dichloromethane afforded 170 mg (47%) of 6b as
white crystals: mp 118-119 °C; IR 3050, 2948, 1622, 1430,
p r op a n on e, 9a (Typ ica l P r oced u r e). Butyllithium in hex-
ane (0.11 mL of 2.5M solution) was mixed with benzenethiol
(31 mg, 0.28 mmol) in dichloromethane (1 mL) under nitrogen
at 0 °C. Then, a solution of ylide 6a (194 mg, 0.28 mmol) in
dichloromethane (10 mL) was added to this mixture. The
resulting mixture was stirred for 5 h at 0 °C and then left
overnight at room temperature. Then the mixture was filtered
and the organic solution was concentrated in a vacuum to yield
product 9a in the form of a slightly yellow solid (106 mg,
89%): mp 214-218 °C;18 1H NMR (CDCl3) δ 7.8-7.0 (m, 20H),
2.35 (s, 3H); 13C NMR (CDCl3) δ 196.8, 133.5, 133.1, 131.8,
129.2, 128.6, 127.2, 125.9, 126.6 (d, J CP ) 100 Hz), 55.5 (d,
J CP ) 104 Hz), 25.5; FAB HRMS m/z 427.13188 (M + H)+,
calcd for C27H24OPS 427.12855. Ylide 9a was further converted
to the known19 (Z)-4-phenyl-3-phenylsulfanyl-3-buten-2-one,
10a , by treatment with benzaldehyde at room temperature.
Rea ction of Com p ou n d 9b in Situ w ith Ben za ld eh yd e.
In a similar procedure, the reaction of ylide 6b (200 mg, 0.28
mmol) with benzenethiol (31 mg, 0.28 mmol) in dichlo-
romethane afforded 101 mg (85%) of crude 9b as a yellow oil,
which was further converted to the known20 (Z)-methyl-2-
(phenylsulfanyl) cinnamate, 10b, by treatment with benzal-
dehyde at room temperature. Compound 10b was isolated by
column chromatography (silica gel, hexane/ethyl acetate, 10:
1) to yield 49 mg (40%): 1H NMR (CDCl3) δ 8.1-7.1 (m, 11H),
3.7 (s, 3H);19 CI HRMS m/z 271.0815 [M + H]+, calcd for
1
1280, 1192, 1098, 1031, 1010 cm-1; H NMR (CDCl3) δ 7.68-
7.48 (m, 20H), 7.29 (d, 2H, J ) 8 Hz), 7.09 (d, 2H, J ) 8 Hz),
3.60 (s, 3H), 2.31 (s, 3H); 13C NMR (CDCl3) δ 168.3, 143.8,
138.8, 135.0, 133.7, 132.1, 131.0, 129.5, 129.3, 128.3, 126.1,
123.8 (d, J CP ) 93.4 Hz), 119.9, 61.5 (d, J CP ) 103 Hz), 52.5,
21.3. Anal. Calcd for C34H30IO5PS: C, 57.63; H, 4.27. Found:
C, 58.02; H, 4.28.
P h e n y lio d o n iu m [(t r ip h e n y lp h o s p h o r a n y lid e n e )-
a ceton itr ile] Tosyla te, 6c. A solution of reagent 5 (200 mg,
0.51 mmol) in freshly distilled acetonitrile (20 mL) was added
to the solution of ylide 2c (153 mg, 0.51 mmol) in acetonitrile
(5 mL) at 0 °C under nitrogen. The resulting clear yellow
solution was stirred for 2 h at 0 °C and left overnight at room
temperature. The resulting solution was concentrated in a
vacuum, yielding a slightly yellow oil. The oil was recrystal-
lized from acetonitrile and diethyl ester to afford 0.175 g (51%)
of product 6c as yellow crystals: mp 102-107 °C (dec); IR
3051, 2916, 2864, 2148, 1918, 1472, 1171, 1031 cm-1; 1H NMR
(CDCl3) δ 7.74-7.5 (m, 20H), 7.3 (d, 2H, J ) 8 Hz), 7.07 (d,
2H, J ) 8 Hz), 2.3 (s, 3H); 13C NMR (CDCl3) δ 143.5, 138.9,
134.6, 133.7, 132.7, 131.3, 130.9, 129.8, 128.4, 125.9, 122.0 (d,
J CP ) 93.4 Hz), 120.6, 33.8 (d, J CP ) 99 Hz), 21.2. Due to the
compound’s low stability, C, H, N analysis was not possible.
1-I o d o -1-(t r ip h e n y lp h o s p h o r a n y lid e n e )-2-p r o p a -
n on e, 7a (Typ ica l P r oced u r e). A solution of potassium
iodide (240 mg, 1.4 mmol) in methanol (20 mL) was added to
the solution of compound 6a (200 mg, 0.29 mmol) in methanol
(30 mL) under a nitrogen atmosphere at 0 °C. The resulting
yellow mixture was stirred overnight at room temperature.
The formation of a slightly yellow precipitate was observed.
The precipitate was filtered and dried in a vacuum to yield
C
16H15SO2 271.0793.
Typ ica l P r oced u r e for th e P r ep a r a tion of P h osp h o-
r a n yl-Der ived Ben ziod oxoles. 1-[2-Oxo-1-(tr ip h en yl-λ5-
p h osp h a n ylid en e)p r op yl]-1H-1λ3-ben zo[d ][1,2]iod oxol-3-
(18) Zbiral, E.; Werner, E. Tetrahedron Lett. 1984, 25, 1111.
(19) Deng, G.; Huang, Z.; Yu, X.; Huang, X. J . Chem. Res., Synop.
1999, 144.
(20) Andres, D. F.; Laurent, E. G.; Marquet, B. S.; Benotmane, H.;
Bensadat, A. Tetrahedron 1995, 51, 2605.
1022 J . Org. Chem., Vol. 68, No. 3, 2003

Phosphoranyl-Derived Iodanes
on e, 12a . A sample of 1-acetoxybenziodoxole 11 (200 mg, 0.65
mmol) was dissolved in dichloromethane (3.5 mL) and stirred
under nitrogen for 30 min, then trimethylsilyl triflate (145 mg,
0.65 mmol) was added, and after 10 min of stirring, a solution
of pyridine (155 mg, 1.95 mmol) in dichloromethane (0.5 mL)
was added. The reaction mixture was additionally stirred for
2 h at room temperature. A solution of ylide 2a (207 mg, 0.65
mmol) in dichloromethane (0.1 mL) was then added to the
reaction mixture. The mixture was stirred overnight at room
temperature. The resulting clear solution was washed with
distilled water and dried with anhydrous sodium sulfate.
Solvents were removed in a vacuum to afford a colorless oil,
which was recrystallized from dichloromethane and diethyl
ether to yield 157 mg (43%) of 12a in the form of white
crystals: mp 175-176 °C; IR (KBr) 3048, 1635, 1610, 1535,
169.4 (d, J CP ) 13 Hz), 167.1, 134.1, 133.7, 133.2, 132.2, 130.2,
129.7, 129.2, 125.0 (d, J CP ) 98.7 Hz), 122.9, 117.3, 52.1, 26.7
(d, J CP ) 98.2 Hz). Anal. Calcd for C28H22IO4P‚H2O: C, 56.20;
H, 4.04; I, 21.21. Found: C, 56.30; H, 3.87; I, 20.72. For X-ray
structure see ref 8.
Rea ction of Com p ou n d 12a w ith Tr iflu or om eth a n e-
su lfon ic Acid . A sample of compound 12a (200 mg, 0.35
mmol) was dissolved in dichloromethane (25 mL) and stirred
under nitrogen at 0 °C for 30 min, then trifluoromethane-
sulfonic acid (53 mg, 0.35 mmol) was added. The reaction
mixture was stirred overnight at room temperature, then the
solvent was removed in a vacuum to afford 250 mg of colorless
oil, which, according to 1H and 13C NMR spectra, was a mixture
of phosphonium salt 13 and 1-hydroxybenziodoxole 14. Careful
crystallization of this oil from dichloromethane and diethyl
ether afforded 137 mg (83%) of phosphonium salt 13 in the
form of white crystals: mp 133-135 °C; IR (KBr) 3048, 2930,
2300, 1719, 1660, 1255, 1164 cm-1; 1H NMR (CDCl3) δ 7.7 (m,
15H), 5.17 (d, J CP ) 11.7 Hz, 2H), 2.47 (s, 3H); 13C NMR
(CDCl3) δ 200.4 (CdO), 134.8 (CH), 133.5 (CH), 130.1 (CH),
1
1361, 1303, 1010 cm-1; H NMR (CDCl3) δ 8.38 (d, 1H, J ) 8
Hz), 7.8 (d, 1H, J ) 8 Hz), 7.8-7.4 (m, 17H), 2.47 (s, 3H); 13
C
NMR (CDCl3) δ 194.6, 166.9, 134.1, 133.4, 133.2, 132.6, 132.5,
130.2, 129.4, 124.7 (d, J CP ) 92.7 Hz), 122.5, 117.4, 44.4 (d,
J CP ) 91.8 Hz), 27.8; ES MS m/z (%) 565 (100), [M + H]+, 317
(83), [M - IC6H4CO2]+. Anal. Calcd for C28H22IO3P‚H2O: C,
57.75; H, 4.15; I, 21.79. Found: C, 57.81; H, 3.94; I, 22.05.
For X-ray structure see ref 8.
120.1 (q, SO2CF3), 118.3 (d, J CP ) 89.7 Hz, CP), 38.9 (d, J CP
)
59.9 Hz, CH2P); FAB MS m/z (%) 319 (100), [M - OTf]+. Anal.
Calcd for C22H20F3O4PS: C, 56.41; H, 4.30; S, 6.85. Found: C,
56.20; H, 4.36; S, 7.00.
(3-Oxo-3H-1λ3-ben zo[d ][1,2]iod oxol-1-yl)(tr ip h en yl-λ5-
p h osp h a n ylid en e)a cetic Acid Meth yl Ester , 12b. In a
similar procedure, the reaction of 1-acetoxybenziodoxole 1 (200
mg, 0.65 mmol) with ylide 2b (217 mg, 0.65 mmol) afforded
174 mg (46%) of product 12b in the form of white crystals:
mp 151-152 °C; IR (KBr) 3055, 1602, 1435, 1355, 1275, 1200
Ack n ow led gm en t. This work was supported by a
research grant from the National Science Foundation
(NSF/CHE-0101021) and by a CRDF award (RC2-2216).
1
cm-1; H NMR (CDCl3) δ 8.32 (d, 1H, J ) 8 Hz), 7.81 (d, 1H,
J ) 8 Hz), 7.6-7.4 (m, 17H), 3.55 (s, 3H); 13C NMR (CDCl3) δ
J O026604Y
J . Org. Chem, Vol. 68, No. 3, 2003 1023