The first synthesis and isolation of 'bis(aryloxy)phosphorothioylsulfenyl iodides' (= bis(aryloxy)phosphinesulfenyl iodide P-sulfides) from the reaction of S,S′-(diphenylstannylene) O,O,O′,O′-tetraaryl bis[phosphorodithioates] (= [(diphenylstannylene)bis(

Article abstract of DOI:10.1002/1522-2675(200208)85:8<2559::AID-HLCA2559>3.0.CO;2-9

S,S′-(Diphenylstannylene) O,O,O′,O′-tetraaryl bis[phosphorodithioates] (=[(diphenylstannylene)bis- (thio)]bis[bis(aryloxy)phosphine P-sulfides]) 5 react with N-iodosuccinimide (NIS) in CH₂Cl₂ at -30° under A to give 'bis(aryloxy)phos

Full text of DOI:10.1002/1522-2675(200208)85:8<2559::AID-HLCA2559>3.0.CO;2-9

Helvetica Chimica Acta Vol. 85 (2002)
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The First Synthesis and Isolation of −Bis(aryloxy)phosphorothioylsulfenyl
Iodides× (ˆ Bis(aryloxy)phosphinesulfenyl Iodide P-Sulfides) from the
Reaction of S,S'-(Diphenylstannylene) O,O,O',O'-Tetraaryl
Bis[phosphorodithioates]
(ˆ [(Diphenylstannylene)bis(thio)]bis[bis(aryloxy)phosphine P-Sulfides])
with N-Iodosuccinimide
by Min Shi*a) and Shinji Katob)
a) State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,
Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032 China (e-mail: Mshi@pub.sioc.ac.cn)
b) Department of Chemistry, Faculty of Engineering, Gifu University, Yanagido, Gifu 501-1193 Japan
Dedicated to Professor Shinji Kato on the occasion of his retirement
S,S'-(Diphenylstannylene) O,O,O',O'-tetraaryl bis[phosphorodithioates] (ˆ [(diphenylstannylene)bis-
(thio)]bis[bis(aryloxy)phosphine P-sulfides]) 5 react with N-iodosuccinimide (NIS) in CH2Cl2 at À308 under
A to give −bis(aryloxy)phosphorothioylsulfenyl iodides× (ˆ bis(aryloxy)phosphinesulfenyl iodide P-sulfides) 6
(Scheme 3), which can readily react in situ with 4-methylbenzenecarbodithioic acid, thiol, and cyclohexene to
afford the corresponding unsymmetrical disulfides and the adduct in good yields as the novel electrophilic
dithiophosphorylating reagents (Schemes 4 and 5). By adding hexane into the solution at À308 after reaction of
5 with NIS, the −phosphorothioylsulfenyl iodides× 6 can be isolated as yellow solids in good yields (see Table).
Introduction. Phosphorodithioic acid derivatives such as (RO)2P(ˆS)SR' and
[(RO)2P(ˆS)]2Sx (x ˆ 1, 2, 3, 4 etc.) are of great importance because of their wide
application as pesticides [1] and lubricating additives, etc. [2][3]. For dithiophosphor-
ylation, the nucleophilic reagents such as alkali-metal phosphorodithioates
(RO)2P(ˆS)SNa [4] and ammonium phosphorodithioates (RO)2P(ˆ S)S(NH2R'2)
[4] have been widely employed. In contrast, −phosphorothioylsulfenyl halides
(ˆ phosphinesulfenyl halide P-sulfides) (RO)2PS(ˆS)X (X ˆ Cl, Br, I), which are
potential electrophilic dithiophosphorylating reagents, have rarely been investigated
due to their thermal instability and difficult synthesis.
To the best of our knowledge, only Almasi and co-workers [5 8] reported in 1962
that −bis(alkyloxy)phosphorothioylsulfenyl chlorides× 1 can be obtained by the reaction
of −bis(alkyloxy)phosphorothioylsulfenamides× (ˆ bis(alkyloxy)phosphinesulfenamide
P-sulfides) 2 with hydrochloric acid (Scheme 1). Moreover, in 1982, Michlaski et al.
indicated that −bis(alkyloxy)phosphorothioylsulfenyl bromides× 3 can be isolated from
the reaction of phosphorodithioic acid O,O-dialkyl S-(trimethylsilyl) esters 4 with
bromine (Scheme 1). Very recently, further details of this reaction have been disclosed
[10]. These methods, however, suffer from two main drawbacks: i) the starting
materials are not readily available, and ii) the starting compounds 3 are very prone to
hydrolysis. In addition, the compounds 2 and 4 synthesized according to these
procedures are oily substances, so their purification is very difficult.

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Helvetica Chimica Acta Vol. 85 (2002)
Scheme 1
On the other hand, in our laboratory, the synthetic methods to furnish −acylsulfenyl
halides× RC(ˆO)SX (X ˆ Cl, Br, I), which are also potential electrophilic thiocarbox-
ylating reagents, have been developed. Thus, the −acylsulfenyl halides× 2a were readily
obtained from the reaction of silver [11], mercury [12], zinc [13], and tin carbothiolates
1a [14][15] with halogen or N-halosuccinimides (NXS, X ˆ Cl, Br, I) (Scheme 2).
These results suggest that −phosphorothioylsulfenyl halides× might be synthesized by
the reaction of phosphorodithioic acid metal salts with N-halosuccinimide or halogens.
In fact, we have synthesized the −phosphorothioylsulfenyl bromides× 3 from the
reaction of S,S'-(diphenylstannylene) O,O,O',O'-tetraalkyl or O,O,O',O'-tetraarylbis-
[phosphorodithioates] 5 with N-bromosuccinimide (NBS) in CH2Cl2 [16]. But we
could not isolate the −bis(aryloxy)phosphorothioylsulfenyl iodides× 6. In this paper, we
wish to report the synthesis and isolation of bis(aryloxy)phosphorothioylsulfenyl
iodides 6 from the reaction of S,S'-(diphenylstannylene) O,O,O',O'-tetraaryl bis-
[phosphorodithioates] (ˆ [diphenylstannylenebis(thio)]bis[bis(aryloxy)phosphine P-
sulfides]) 5 with N-iodosuccinimide (NIS).
Scheme 2
Results and Discussion.
Bis(aryloxy)phosphorothioylsulfenyl iodides 6 are
unknown compounds because they are very labile, and their isolation from reaction
mixtures is very difficult. So far, no successful isolation of this kind of compound has
been reported. During our own investigation on the synthesis and isolation of 6, we
confirmed that, at low temperature (À 308), diphenoxyphosphorothioylsulfenyl iodide
6a was indeed formed by trapping reagents such as a carbodithioic acid, ethanethiol, or
cyclohexene. In a typical trapping experiment, 5a was treated with NIS in CH2Cl2 at
À308 for 2 h, and, then, the carbodithioic acid was added and the mixture stirred at

Helvetica Chimica Acta Vol. 85 (2002)
2561
Scheme 3
Scheme 4
À308 for 8 h (Scheme 4). After evaporation, the crude product was purified by column
chromatography (silica gel) to give 7a as a red oily product in high yield (86%). Its
structure was established on the basis of spectroscopic data.
Similarly, the trapping experiments with ethanethiol and cyclohexene gave the
corresponding product 7b and 7c, respectively, in moderate yields (80 and 60%, resp.)
(Scheme 4). All these results suggest that the bis(aryloxy)phosphorothioylsulfenyl
iodides 6 were unambiguously formed at À308.
We then attempted to isolate compounds 6 from the reaction mixture, although it is
very difficult because evaporation of the mixture after reaction at room temperature,
bis(aryloxy)phosphorothioylsulfenyl iodides 6 immediately decomposed to precipitate
iodine (I2), and the reaction solution turned from yellow-orange to dark red. After
tremendous efforts, we finally found that −bis(aryloxy)phosphorothioylsulfenyl iodides×
6a d could be precipitated from the reaction mixture at À308 by adding hexane. Quick
filtration of the resulting solid allowed us to isolate 6a d in good yield (see Table).
Repeated recrystallization from CH2Cl2/hexane at À308 finally gave 6 in quite pure
form. The structure of the −bis(aryloxy)phosphorothioylsulfenyl iodides× 6 were
established by spectroscopic data (see Table) and microanalyses. This is the first
report on the isolation of bis(aryloxy)phosphorothioylsulfenyl iodides 6.

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Helvetica Chimica Acta Vol. 85 (2002)
Table. Yields, Spectral Data, and Physical Properties of (ArO)2P(ˆS)SI (6a d)
Ar of (ArO)2P(ˆS)SI
Yielda) [%]
M.p. [8]
IR (KBr): nÄ(PˆS) [cmÀ1
]
31P-NMRb) [d]
6a
6b
6c
6d
C6H5
74
80
60
50
85 86
87 88
104 105
95 96
635, 845
635, 845
635, 845
635, 845
67.7
68.2
70.0
69.2
4-MeC6H4
4-MeOC6H4
4-ClC6H4
a) Isolated yield. b) External standard: 85% H3PO4.
Conclusions. We found that bis(aryloxy)phosphorothioylsulfenyl iodides 6 can be
isolated from the reaction mixture as yellow precipitates after addition of hexane at low
temperature (À 308). Efforts are underway to elucidate the mechanistic details of this
reaction and to identify systems enabling similar syntheses of other substrates and
subsequent transformations thereof.
Experimental Part
General. Organic solvents were dried by standard methods when necessary. Commercially available
reagents were used without further purification. TLC Monitoring: Huanghai-GF254 silica-gel-coated plates.
Flash column chromatography (FC): silica gel, 200 300 mesh. M.p.: Yanagimoto micro-melting-point
apparatus; uncorrected. 1H-NMR Spectra: Bruker AM-300 spectrometer; in CDCl3 with SiMe4 as internal
standard; d in ppm, J in Hz. Mass spectra: Hewlett-Packard 5989 instrument; for high resolution, Finnigan
MA ‡ spectrometer. Some of the solid compounds reported in this paper gave satisfactory CHN microanalyses
with Carlo-Erba 1106 analyzer.
Reaction of S,S'-(Diphenylstannylene) O,O,O',O'-Tetraaryl Bis[phosphorodithioates] with NIS: General
Procedure. To S,S'-(diphenylstannylene) O,O,O',O'-tetraphenyl bis[phosphorodithioate] (ˆ([diphenylstan-
nylene)bis(thio)]bis[diphenoxyphosphine P-sulfide]; 5a; 835 mg, 1.0 mmol) in CH2Cl2 (20 ml), N-iodosuccini-
mide (NIS) (270 mg, 1.2 mmol) was added at À308 under Ar ( ! immediately orange soln). The mixture was
stirred at À308 for 2 h. Anh. hexane (16 ml) was added to the mixture to give a yellow precipitate. After
filtration, the obtained solid was recrystallized from CH2Cl2 (8 ml)/hexane (20 ml): 301 mg (74%) of
diphenoxyphosphorothioylsulfenyl iodide (ˆdiphenoxyphosphinesulfenyl iodide P-sulfide; 6a). Yellow solid.
M.p. 85 868. IR (CHCl3): 635, 845 (PˆS). 1H-NMR (CDCl3): 7.13 7.38 (m, Ph). 31P-NMR (121 MHz, CDCl3,
.
‡
85% H3PO4): 67.7. EI-MS: 408 (M ). Anal. calc. for C12H10IO2PS2: C 35.31, H 2.47; found: C 35.27, H 2.33%.
We thank the State Key Project of Basic Research (Project 973) (No. G2000048007) and the National
Natural Science Foundation of China for financial support (20025206 and 29972012). We also thank the Inoue
Photochirogenesis Project (ERATO, JST) for chemical reagents.
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Helvetica Chimica Acta Vol. 85 (2002)
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Received April 26, 2002