Reactions of selenothioic acid S-esters with trivalent phosphorus compounds: New synthetic methods for α-phosphoryl alkyl sulfides and alkyl selenides

Article abstract of DOI:10.1039/a909469e

The reaction of selenothioic acid S-esters 1 with trialkyl phosphites proceeds smoothly with the extrusion of selenium atoms to afford α-phosphoryl sulfides 2 in good to high yields. A similar reaction takes place more easily with dimethyl phenylphosphonite and methyl diphenylphosphinite, although the ketene selenothioacetals 3 are also formed as by-products in increased yields. The use of diselenoic acid esters If and 1g gives α-phosphoryl selenides 2m and 2n. The products exhibit characteristic chemical shifts and coupling constants in their ³¹P NMR spectra. The structure of α-phosphoryl selenide 2n is confirmed by X-ray molecular structure analysis. The reaction with triphenylphosphine leads to oxidative dimerization of ester 1d to give divinyl diselenide 4 in good yield. A catalytic amount of triphenylphosphine is also effective to form divinyl diselenide 4. The reaction may begin with the nucleophilic attack of triphenylphosphine on the carbon atom of the selenocarbonyl group of ester 1d. Details of the reaction pathway leading to α-phosphoryl sulfides 2 are also discussed. The reaction with menthyl diphenylphosphinite 12 has suggested that the reaction may proceed via initial nucleophilic attack of trivalent phosphorus compounds bearing alkoxy groups on the selenium atom of esters 1. The intermediacy of phosphonium ylide 14 has also been supported by the reaction of the ester 1h which gives 1,4-oxathiane 15.

Full text of DOI:10.1039/a909469e

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Reactions of selenothioic acid S-esters with trivalent phosphorus
compounds: new synthetic methods for ꢀ-phosphoryl alkyl sulfides
and alkyl selenides
1
Toshiaki Murai, Chiyoko Izumi, Toshihide Itoh and Shinzi Kato*
Department of Chemistry, Faculty of Engineering, Gifu University, Yanagido Gifu 501-1193,
Japan
Received (in Cambridge, UK) 30th November 1999, Accepted 17th January 2000
The reaction of selenothioic acid S-esters 1 with trialkyl phosphites proceeds smoothly with the extrusion of
selenium atoms to afford α-phosphoryl sulfides 2 in good to high yields. A similar reaction takes place more easily
with dimethyl phenylphosphonite and methyl diphenylphosphinite, although the ketene selenothioacetals 3 are also
formed as by-products in increased yields. The use of diselenoic acid esters 1f and 1g gives α-phosphoryl selenides
2m and 2n. The products exhibit characteristic chemical shifts and coupling constants in their 31P NMR spectra.
The structure of α-phosphoryl selenide 2n is confirmed by X-ray molecular structure analysis. The reaction with
triphenylphosphine leads to oxidative dimerization of ester 1d to give divinyl diselenide 4 in good yield. A catalytic
amount of triphenylphosphine is also effective to form divinyl diselenide 4. The reaction may begin with the
nucleophilic attack of triphenylphosphine on the carbon atom of the selenocarbonyl group of ester 1d. Details
of the reaction pathway leading to α-phosphoryl sulfides 2 are also discussed. The reaction with menthyl
diphenylphosphinite 12 has suggested that the reaction may proceed via initial nucleophilic attack of trivalent
phosphorus compounds bearing alkoxy groups on the selenium atom of esters 1. The intermediacy of phosphonium
ylide 14 has also been supported by the reaction of the ester 1h which gives 1,4-oxathiane 15.
Introduction
Results and discussion
It is of current interest to study the syntheses and reactions of
selenocarbonyl compounds.1 Much attention has been paid to
the higher reactivity of the selenocarbonyl group compared
to the reactivity of ordinary carbonyl and thiocarbonyl com-
pounds. The patterns of the reactions of selenocarbonyl com-
pounds are moderately affected by the substituents attached to
the carbon atom of the selenocarbonyl group. For example, the
reaction of triseleno- and dithioselenocarbonates with trialkyl
phosphites has been used as a synthetic method for fulvalene
derivatives.2 The treatment of selenoic acid O-alkyl esters
(RC(Se)ORЈ) with triethylphosphine has also been reported to
generate purple intermediates which were converted to ordinary
esters by reaction with oxygen.3 Very recently, convenient
methods for the synthesis of selenothioic acid S-esters (RC-
(Se)SRЈ)4 and diselenoic acid esters (RC(Se)SeRЈ)5 1 have been
The reaction of selenothioic acid S-butyl ester 1a with trimethyl
phosphite was carried out (Scheme 1). The results are summar-
ised in Table 1. The use of MeOH, CH3CN, toluene and hexane
as a solvent gave α-phosphoryl sulfide 2a and ketene seleno-
thioacetal 3a as the products. In the reaction with 1 equiv. of
trimethyl phosphite in toluene, the ratio of 3a increased along
with the recovery of starting ester 1a (entry 4), whereas in other
cases the ratio of products 2a and 3a was about 2:1. The
reaction of ester 1a with trimethyl phosphite for 10 min at
85 ЊC in toluene afforded the products 2a and 3a in 57% and
31% isolated yields, respectively, along with 31% of trimethyl
selenophosphate (entry 5). These results are in marked contrast
to the reaction of dithioic acid esters with trimethyl phosphite
where the condensation reaction of the esters took place and
α,β-unsaturated dithioic acid esters were obtained only in low
yields after 8 h.11
Second, the reactions with other trialkyl phosphites, dimethyl
phenylphosphonite [PhP(OMe)2], methyl diphenylphosphinite
[Ph2POMe] and triphenylphosphine [PPh3] were carried out
(Table 2). The use of triethyl phosphite and triisopropyl phos-
phite gave products 2 along with ketene selenothioacetals 3
(entries 1 and 2) under identical reaction conditions to the reac-
tion with trimethyl phosphite (Table 1, entry 6). However, the
reaction with triphenyl phosphite [(PhO)3P] did not proceed,
and the starting ester 1a was recovered. The reaction of ester 1a
with PhP(OMe)2, Ph2POMe and PPh3 was complete within
30 min. When one or two alkoxy groups were attached to the
phosphorus atom, a similar transformation proceeded to afford
α-phosphoryl and α-phosphinoyl sulfides (entries 3–5). On the
contrary, the use of PPh3 gave a complex mixture. In the
reaction with PhP(OMe)2 two diastereomers were formed in a
nearly equal ratio (entry 3). To improve the diastereoselectivity
of product 2d, MeOH, Et2O, CH3CN, hexane and THF were
Scheme 1
established. During the course of our studies on the reactivity
of esters 1 we found that treatment of esters 1 with trialkyl
phosphites provided a new synthetic method for α-phosphoryl
sulfides.6 α-Phosphoryl and α-phosphinoyl alkyl sulfides play an
important role in organic chemistry.7,8 They have been used as
key intermediates of syntheses of olefins involving Wittig-type
reactions.9 They have also been employed as precursors of
phosphorylalkyl radicals.10 In this paper, we report in detail on
the reactions of esters 1 and trivalent phosphorus compounds
and their reaction pathways.
DOI: 10.1039/a909469e
J. Chem. Soc., Perkin Trans. 1, 2000, 917–924
This journal is © The Royal Society of Chemistry 2000
917

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Table 1 Reactions of selenothioic acid S-butyl ester 1a with trimethyl phosphitea
Yield (%)b,c
(MeO)3P
Entry
Solvent
(equiv.)
Temp./ЊC
Time
2a
3a
1
2
3
4
5
6
7
8
MeOH
CH3CN
toluene
toluene
toluene
toluene
hexane
hexane
3
3
3
1
3
5
3
3
rt
rt
rt
85
85
65
rt
6 h
6 h
6 h
40 min
10 min
40 min
6 h
71
67
60
51
68 (57)
66
55
29
33
23
42
32 (31)
34
11
69
1 h
62
38
a The ester 1a (0.5 mmol) was stirred with trimethyl phosphite in a solvent (2.5 mL). b Yield was determined on the basis of 1H NMR spectra of the
reaction mixture. c Isolated yields are shown in parentheses.
Table 2 Reaction of selenothioic acid S-butyl ester 1a with phos-
phorus compoundsa
Reaction
conditions
Product
Entry
1
yield (%)b
(EtO)3P
toluene
Fig. 1 Stable conformation of compound 2.
85 ЊC, 10 min
gave a complex mixture (entry 2). PhP(OMe)2 and Ph2POMe
also reacted smoothly with α-disubstituted ester 1d (entries 4
and 7). In the former case one of the diastereomers was formed
predominantly, although the stereochemistry of the product
was not determined. The reaction of dioxaphospholane took
place accompanied by the ring opening of the dioxaphos-
pholane to afford product 2j in 70% yield (entry 5). Finally,
diselenoic acid esters 1f and 1g were reacted with Ph2POMe to
give α-phosphoryl selenides 2m and 2n in 84 and 47% yields,
respectively (entries 8 and 9).
(PriO)3P
toluene
85 ЊC, 30 min
2
3
PhP(OMe)2
toluene
rt, 30 min
The α-phosphoryl sulfides obtained showed characteristic 31
P
NMR spectra (Table 4). The signals of α-phosphoryl sulfides
2a, 2g, 2h and 2k were observed at about δ 29 (entries 1–4). The
replacement of a methoxy group with a phenyl group shifted
the signals to lower fields by about 15 ppm (entries 8 and 9).
Interestingly, further replacement of a methoxy group with a
phenyl group, namely, α-diphenylphosphoryl sulfides 2f and 2l
showed the signals higher than those of α-methoxy(phenyl)-
phosphoryl sulfides 2d and 2i (entries 10 and 11). In contrast,
the coupling constants between the phosphorus atom and the
carbon atom (1JP-C) became larger as the number of alkoxy
groups increased. This may be understood as follows. The con-
former of 2 shown in Fig. 1 appears to be the most stable
among several possible conformers. Then, stereoelectronic
effects may be present between an O–P bond and the C–S bond.
In other words, delocalization of the electrons from the C–S
σ orbital to the P–O σ* orbital may occur, and this enhances
the strength of the bond between the phosphorus and carbon
atoms. As a matter of fact, 1J value of 2b is larger than that of
Bu-P(O)(OEt)2 (1JP-C = 140.9 Hz) by about 10 Hz.12 Finally, no
substantial difference was observed between the sulfides and
PhP(OMe)2
Et2O
rt, 1 h
4d
Ph2POCH3
toluene
rt, 5 min
5
a The ester 1a (0.5 or 1 mmol) was stirred with phosphorus com-
pounds (2 or 3 equiv.) in a solvent (2.5 or 5 mL). b Isolated yield. c The
ratio of the stereoisomers was determined on the basis of 13C NMR
spectra of the reaction mixture. d Ethaneselenothioic acid S-tert-butyl
ester was used as the ester.
used as solvent, but the ratio of the stereoisomers did not
change. The use of selenothioacetic acid S-tert-butyl ester gave
product 2e with better selectivity, although the yield of product
2e decreased (entry 4).
2
selenide (entries 10–12), although in the latter case, a JP-Se
coupling was observed (36.6 Hz). The structure of α-phosphoryl
selenide 2n was further confirmed by X-ray analysis. Fig. 2
shows an ORTEP drawing of 2n, and selected bond lengths and
bond angles are listed in Table 5. The bond length of Se1–C1 is
1.981(3) Å, which is close to the value of the carbon–selenium
single bond of trans-2-dimethoxyphosphoryl-1,3-diselenane
(C–Se: 1.97 Å).13 The torsion angle of Se1–C1–P1–O1 of 2n
is 56.9(2)Њ. The α-phosphoryl selenide exists in a bisecting
conformation in the solid state. A substantial non-bonded
interaction, which has recently been discussed in compounds
containing selenium and oxygen atoms,14 was not observed.
Next, α-substituted esters
1 were used as a starting
material. The results are summarised in Table 3. The reaction of
α-mono- 1b and α-disubstituted esters 1d and 1e with trimethyl
phosphite successfully proceeded to give the corresponding
α-phosphoryl sulfides in good yields, although the reaction time
was strongly affected by the substituents next to the seleno-
carbonyl group (entries 1, 3 and 6). In these reactions the
formation of ketene selenothioacetals 3 was suppressed. On the
contrary, the reaction with esters 1c, in which a hydroxy group
was attached to the carbon atom β to the selenocarbonyl group,
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J. Chem. Soc., Perkin Trans. 1, 2000, 917–924

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Table 3 Reaction of selenothioic acid S-butyl esters 1 with trivalent
Table 4 Spectroscopic data of 2a
phosphorus compoundsa
31P NMR
1JP-C
/
d
Reaction
conditions
Product
Entry
1
Compoundb,c
δ (ppm)
Hz
Entry
1
Ester
yield (%)b
29.9
29.3
150.2
151.1
(MeO)3P
85 ЊC
1.5 h
2
3
(MeO)3P
85 ЊC
1 h
2
3
Complex mixture
29.5
28.1
149.2
149.2
(MeO)3P
110 ЊC
6 h
4
5
PhP(OMe)2
110 ЊC
20 min
4
5
1d
1d
28.8
28.5
149.2
144.7
6
7
8
27.6
25.5
151.1
152.1
110 ЊC
5 h
(MeO)3P
110 ЊC
6 h
6
7
44.3
44.4
103.4
104.3
Ph2POMe
110 ЊC
10 min
1d
9
44.0
43.4
102.9
104.8
(MeO)3P
110 ЊC
4 h
10
11
33.8
31.3
71.2
72.2
8
9
Ph2POMe
rt
15 min
a The ester 1 (0.5, 0.8 or 1 mmol) was stirred with trimethyl phosphite
12
30.7
68.3
(3 equiv.) in toluene (2.5 or 5 mL). b Isolated yield. c R represents
CH2CH᎐CH2. d The ratio of diastereomers is shown in parentheses. e RЈ
᎐
represents CH2CBr᎐CH2.
a CDCl3 was used as a solvent. b R represents CH2CH᎐CH2. c RЈ repre-
᎐
᎐
sents CH2CBr᎐CH2. d Coupling constant was determined on the basis
᎐
of 13C NMR spectra.
Finally, the reaction of α-disubstituted ester 1d with PPh3
was carried out (Scheme 2). The use of 1 equiv. of PPh3 in
CH3CN gave diselenide 4 in 68% yield. Interestingly, a catalytic
amount of PPh3 was effective for the conversion of 1d to 4. A
plausible reaction pathway leading to 4 is outlined in Scheme 3.
Nucleophilic attack of PPh3 on the carbon atom of the seleno-
carbonyl group of 1d initially may take place to form 5. Then,
migration to the selenium atom of the proton α to the seleno-
carbonyl group proceeds to generate eneselenol 6, followed by
air oxidation to give 4. In general, it is known that diselenides
are easily reduced to the corresponding selenols with sodium
borohydride in MeOH at room temperature,15 but in this case
the reaction gave ester 1d rather than eneselenol 6 in 83%
yield.
The reaction pathway using trialkyl phosphites is outlined in
Scheme 4 on the basis of the proposed mechanism of the reac-
tions of thiocarbonyl compounds with trialkyl phosphites.16–18
In the first step, trialkyl phosphites may nucleophilically
J. Chem. Soc., Perkin Trans. 1, 2000, 917–924
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Table 5 Selected bond lengths and angles for compound 2n with esti-
mated standard deviation in parentheses
Bond length/Å
Bond angle (Њ)
Se(1)–C(1)
P(1)–O(1)
P(1)–C(1)
Se(1)–C(2)
P(1)–C(9)
P(1)–C(15)
1.981(3)
1.490(2)
1.819(3)
1.936(3)
1.808(3)
1.805(3)
Se(1)–C(1)–P(1)
C(1)–Se(1)–C(2)
C(1)–P(1)–O(1)
C(1)–P(1)–C(9)
C(1)–P(1)–C(15) 107.5(1)
P(1)–C(1)–C(3) 114.1(2)
106.3(1)
98.0(1)
114.2(1)
106.0(1)
Fig. 2 ORTEP drawing of compound 2n with atomic numbering
scheme.
Scheme 4
the β-elimination of dialkyl phosphites from 9. On the other
hand, two reaction pathways can be proposed for the formation
of the products 2. One involves the intermediate 9 (Path B).
Alternatively, the process involving the initial attack of trialkyl
phosphites on the selenium atom of the esters 1 is possible (path
A). Then, the elimination of Se᎐P(OR) from 10 gives phos-
᎐
3
phonuim salt 11, followed by hydrolysis to give the product
2. To confirm the validity of the proposed reaction pathway
menthyl phosphinite 12 was reacted with ester 1d (Scheme 5).
Scheme 2
Scheme 3
Scheme 5
attack the carbon atom of esters 1 (path B) similarly to the
reaction with PPh3 shown in Scheme 3. Then, intramolecular
rearrangement of the alkyl group on the phosphoryl group of 8
may occur to form 9. A similar rearrangement has been postu-
lated for the reactions of cycloalkanethiones with trialkyl
phosphites.17 The formation of products 3 may be explained by
The reaction proceeded smoothly in 1,2-dichloroethane at 83 ЊC
to afford α-phosphoryl sulfide 2l in better yield than the reac-
tion with Ph2POMe (Table 3, entry 7) along with 75% yield of
selenophosphinite 13. No product having a menthylselanyl
920
J. Chem. Soc., Perkin Trans. 1, 2000, 917–924

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group, which should be formed when the migration of the
menthyl group (analogous to the process from 8 to 9) occurred,
was observed. The formation of menthol as a by-product has
suggested hydrolysis of an intermediate similar to 11. Finally,
the reaction of ester 1h with trimethyl phosphite was carried
out. The reaction was complete within 10 min at 85 ЊC to give
1,4-oxathiane 15 in 40% yield (Scheme 6). The initial reaction
phosphite (0.18 mL, 1.5 mmol) at room temperature. After
being stirred at 85 ЊC (temperature of oil bath) for 10 min under
nitrogen, the resulting mixture was concentrated in vacuo. The
residue was purified by column chromatography on silica gel
using hexane–Et2O (100:0 to 80:20) as the solvent to elute
α-phosphoryl sulfide 2a (0.065 g, 57%) and ketene selenothio-
acetal 3a (0.032 g, 31%).
2-(Dimethoxyphosphoryl)-3-thiaheptane 2a. A colourless oil
(Found: C, 42.37; H, 8.73. C8H19O3PS requires C, 42.47; H,
8.46%); νmax/cmϪ1 3476, 2957, 2873, 2361, 2343, 1458, 1377,
1238, 1184, 1028, 827, 808, 734, 669, 533; δH (400 MHz, CDCl3)
0.92 (3 H, t, J 7.3, CH3), 1.42 (2 H, sex, J 7.4, CH2), 1.49 (3 H,
dd, J 7.4, 3JP-H 17.2, CH3), 1.54–1.62 (2 H, m, CH2), 2.70–2.83
2
(2 H, m, SCH2), 2.85 (1 H, qui, J 7.3, JP-H 7.3, PCHS), 3.82
3
3
(3 H, d, JP-H 10.7, OCH3), 3.84 (3 H, d, JP-H 10.5, OCH3);
δC (100 MHz, CDCl3) 13.6, 16.1, 21.9, 31.3, 31.8, 33.9, 53.4,
53.7; m/z (EI) 226 (Mϩ), 169 (Mϩ Ϫ Bu).
2-(Diethoxyphosphoryl)-3-thiaheptane 2b. A colourless oil
(Found: C, 46.95; H, 9.03. C10H23O3PS requires C, 47.23; H,
9.12%); νmax/cmϪ1 3475, 2933, 2874, 1654, 1456, 1392, 1236,
1164, 1024, 959, 789, 731, 666, 538; δH (400 MHz, CDCl3)
0.92 (3 H, t, J 7.2, CH2CH3), 1.34 (3 H, t, J 7.1, OCH2CH3),
1.35 (3 H, t, J 7.1, OCH2CH3), 1.39–1.46 (2 H, m, CH2CH3),
Scheme 6
selectively takes place on the selenocarbonyl group attached to
the alkylthio group, and phosphonium salt 14 may be formed
as an intermediate, followed by the intramolecular cyclisation
to give product 15.
In conclusion, reactions of selenothioic acid S-esters and
diselenoic acid esters with trivalent phosphorus compounds
have been demonstrated. The reactions provide a new and effi-
cient synthetic method for α-phosphoryl sulfides and selenides.
The reaction may involve nucleophilic attack of trivalent phos-
phorus compounds on the selenium atom of the esters, and
phosphonium salts may be formed as intermediates.
3
1.48 (3 H, dd, J 7.6, JP-H 17.1, PCHCH3), 1.54–1.62 (2 H, m,
SCH2CH2), 2.70–2.86 (3 H, m, SCH2, PCHS), 4.14–4.24 (4 H,
m, OCH2); δC (100 MHz, CDCl3) 13.6, 16.2, 16.4, 16.5, 21.9,
31.3, 31.7, 34.1, 62.5, 62.9; m/z (EI) 254 (Mϩ).
2-(Diisopropoxyphosphoryl)-3-thiaheptane 2c. A colourless
oil (Found: C, 50.84; H, 9.54. C12H27O3PS requires C, 51.04;
H, 9.64%); νmax/cmϪ1 3476, 2978, 2874, 2366, 2345, 1718, 1654,
1456, 1385, 1236, 1178, 1142, 1108, 985, 886, 788, 734, 669, 547,
486; δH (400 MHz, CDCl3) 0.92 (3 H, t, J 7.3, CH2CH3), 1.33–
1.36 (12 H, m, OCH(CH3)CH3), 1.39–1.44 (2 H, m, CH2CH3),
Experimental
General
3
1.45 (3 H, dd, J 7.3, JP-H 16.8, PCHCH3), 1.53–1.61 (2 H, m,
The IR spectra were obtained on a Perkin Elmer FT-IR 1640
spectrophotometer. The H NMR spectra were measured on a
SCH2CH2), 2.70–2.84 (3 H, m, SCH2, PCHS), 4.70–4.83 (2 H,
m, OCH); δC (100 MHz, CDCl3) 13.6, 16.4, 21.9, 23.86, 23.9,
24.1, 24.2, 31.4, 31.8, 34.7, 70.8, 71.3; m/z (EI) 282 (Mϩ).
1
JEOL α-400 (399.7 MHz) in CDCl3. Chemical shifts of protons
are reported in δ values referenced to tetramethylsilane as an
internal standard, and the following abbreviations were used; s:
singlet, d: doublet, t: triplet, q: quartet, qui: quintet, sex: sextet,
hep: heptet, m: multiplet. The 13C NMR spectra were measured
on a JEOL α-400 (100.4 MHz). The 31P NMR (161.7 Hz)
and 77Se NMR (76.2 MHz) spectra were obtained from a JEOL
α-400 spectrometer, and their chemical shifts are expressed in
δ values deshielded with respect to neat PPh3 and Me2Se,
respectively as an external standard. All spectra were acquired
in the proton-decoupled mode; generally 0.05–0.3 mmol solu-
tions in CDCl3 (0.4 mL) were used. The mass spectra (MS) were
taken on Shimadzu GCMS QP1000 (EI mode) or GCMS
9020DF high resolution mass spectrometers. The high reso-
lution mass spectroscopy was taken on a Shimadzu GCMS
9020DF high resolution mass spectrometer. Elemental analyses
were carried out by the Elemental Analysis Center of Kyoto
University. High performance liquid chromatography (HPLC)
was performed using a Japan Analytical Industry LC-908
recycling preparative HPLC coupled to an RI indicator and UV
detector (256 nm). Melting points were determined using a
Yanaco micromelting point apparatus and are uncorrected.
2-Phenyl-1,3,2-dioxaphospholane19 and menthyl diphenyl-
phosphinate20 were prepared according to the literature. All the
starting esters 1 were prepared by the literature method.4 Other
substrates were commercially received.
2-[Methoxy(phenyl)phosphoryl]-3-thiaheptane 2d. A colour-
less oil; νmax/cmϪ1 3454, 3058, 2958, 2872, 2366, 2346, 1592,
1439, 1376, 1222, 1181, 1122, 1039, 793, 747, 697, 654, 542, 509;
δH (400 MHz, CDCl3) (Major) 0.89 (3 H, t, J 7.3, CH2CH3),
3
1.27–1.43 (2 H, m, CH2CH3), 1.39 (3 H, dd, J 7.4, JP-H 16.5,
PCHCH3), 1.45–1.56 (2 H, m, SCH2CH2), 2.58–2.76 (2 H, m,
3
SCH2), 2.86–2.95 (1 H, m, PCHS), 3.74 (3 H, d, JP-H 10.7,
CH3), 7.47–7.60 (3 H, m, Ar), 7.81–7.87 (2 H, m, Ar); (Minor)
0.86 (3 H, t, J 7.2, CH2CH3), 1.27–1.43 (2 H, m, CH2CH3),
3
1.45–1.56 (2 H, m, SCH2CH2), 1.49 (3 H, dd, J 7.4, JP-H 16.0,
PCHCH3), 2.48–2.62 (2 H, m, SCH2), 2.86–2.95 (1 H, m,
PCHS), 3.72 (3 H, d, 3JP-H 10.7, CH3), 7.47–7.60 (3 H, m, Ar),
7.81–7.87 (2 H, m, Ar); δC (100 MHz, CDCl3) (Major) 13.61,
15.8, 21.9, 31.4, 32.1, 37.1, 51.9, 128.1, 128.371, 132.5, 132.7,
132.8, 132.9; (Minor) 13.58, 15.3, 21.8, 31.3, 31.5, 36.7, 51.9,
128.371, 128.372, 132.5, 132.7, 132.8, 132.9; m/z (EI HRMS)
272.10093 (Mϩ, C13H21P2S requires 272.1016728); m/z (EI
LRMS) 272 (Mϩ).
4,4-Dimethyl-2-[methoxy(phenyl)phosphoryl]-3-thiapentane
2e. A colourless solid, mp 53–55 ЊC; νmax/cmϪ1 3502, 2960, 1774,
1654, 1463, 1439, 1366, 1252, 1224, 1176, 1160, 1116, 1037, 805,
766, 752, 700, 660, 590, 546, 509; δH (400 MHz, CDCl3) (Major)
1.16 (9 H, s, SC(CH3)3), 1.51–1.60 (3 H, m, PCHCH3), 2.73–
2.86 (1 H, m, PCHS), 3.74 (3 H, d, 3JP-H 10.9, OCH3), 7.44–7.58
(3 H, m, Ar), 7.82–7.90 (2 H, m, Ar); (Minor) 1.13 (9 H, s,
SC(CH3)3), 1.51–1.60 (3 H, m, PCHCH3), 2.73–2.86 (1 H, m,
PCHS), 3.71 (3 H, d, 3JP-H 11.2, OCH3), 7.44–7.58 (3 H, m, Ar),
7.82–7.90 (2 H, m, Ar); δC (100 MHz, CDCl3) (Major) 18.6,
General procedure for reactions of selenothioic acid S-esters with
trivalent phosphorus compounds
To a solution of ethaneselenothioic acid S-butyl ester 1a
(0.098 g, 0.5 mmol) in toluene (2.5 mL) was added trimethyl
J. Chem. Soc., Perkin Trans. 1, 2000, 917–924
921

View Article Online
30.5, 35.1, 44.2, 51.9, 128.1, 128.3, 132.3, 132.9, 133.0, 133.1;
(Minor) 18.4, 30.5, 34.8, 44.1, 51.9, 128.2, 128.4, 132.3, 132.9,
133.0, 133.1; m/z (EI HRMS) 272.09912 (Mϩ, C13H21O2PS
requires 272.1016728); m/z (EI LRMS) 272 (Mϩ).
5-[(2-Hydroxyethoxy)phenylphosphoryl]-4-prop-2-enyl-6-
thiadec-1-ene 2j. Colourless oil; νmax/cmϪ1 3374, 3076, 2958,
2930, 2873, 2346, 1831, 1639, 1592, 1439, 1379, 1276, 1208,
1120, 1098, 1035, 950, 916, 884, 751, 697, 563; δH (400 MHz,
CDCl3) (Major) 0.87 (3 H, t, J 7.3, CH2CH3), 1.13–1.51 (4 H,
m, CH CH , SCH CH ), 1.91–2.18 (2 H, m, CH CH᎐CH ),
᎐
2
3
2
2
2
2
2-(Diphenylphosphoryl)-3-thiaheptane 2f. A colourless solid,
mp 85.3–87.3 ЊC (Found: C, 67.74; H, 7.25. C18H23OPS requires
C, 67.90; H, 7.28%); νmax/cmϪ1 3056, 2959, 2924, 2362, 1508,
1487, 1438, 1182, 1119, 1072, 1026, 998, 741, 722, 701, 692, 546,
532; δH (400 MHz, CDCl3) 0.83 (3 H, t, J 7.3, CH2CH3), 1.28
(2 H, sex, J 7.3, CH2CH3), 1.44 (2 H, qui, J 7.4, SCH2CH2), 1.55
2.24–2.38 (3 H, m, CHCH CH᎐CH , CH CH᎐CH ), 2.47–2.61
᎐
᎐
2
2
2
2
2
(2 H, m, SCH2), 2.94 (1 H, dd, J 1.0, JP-H 4.9, PCHS), 3.71–
3.76 (1 H, m, OCHH), 3.84–3.90 (2 H, m, OCHH, OH), 4.09–
4.16 (2 H, m, OCH ), 4.96–5.11 (4 H, m, CH᎐CH ), 5.48–5.79
᎐
2
2
(2 H, m, CH᎐CH ), 7.48–7.61 (3 H, m, Ar), 7.83–7.90 (2 H, m,
᎐
2
3
Ar); (Minor) 0.77 (3 H, t, J 7.3, CH2CH3), 1.13–1.51 (4 H, m,
(3 H, dd, J 7.4, JP-H 15.0, PCHCH3), 2.40–2.47 (1 H, m,
CH CH , SCH CH ), 1.91–2.18 (2 H, m, CH CH᎐CH ), 2.24–
᎐
2
3
2
2
2
2
SCHHCH2), 2.50–2.57 (1 H, m, SCHHCH2), 3.30 (1 H, dq,
J 7.3, 2JP-H 9.5, PCHS), 7.45–7.54 (6 H, m, Ar), 7.84–7.94 (4 H,
m, Ar); δC (100 MHz, CDCl3) 13.5, 15.8, 21.6, 31.2, 31.6, 37.3,
128.3, 128.4, 131.4, 131.7, 131.8, 132.0; m/z (EI LRMS) 318
(Mϩ).
2.38 (3 H, m, CHCH CH᎐CH , CH CH᎐CH ), 2.47–2.61 (2 H,
᎐
᎐
2
2
2
2
2
m, SCH2), 2.97 (1 H, dd, J 1.5, JP-H 4.4, PCHS), 3.71–3.76
(1 H, m, OCHH), 3.84–3.90 (2 H, m, OCHH, OH), 4.09–4.16
(2 H, m, OCH ), 4.96–5.11 (4 H, m, CH᎐CH ), 5.48–5.79 (2 H,
᎐
2
2
m, CH᎐CH ), 7.48–7.61 (3 H, m, Ar), 7.83–7.90 (2 H, m, Ar);
᎐
2
δC (100 MHz, CDCl3) (Major) 13.5, 21.6, 31.1, 34.1, 35.0, 35.1,
37.6, 45.71, 62.3, 69.3, 116.8, 117.4, 128.5, 129.8, 132.67,
132.72, 136.7, 137.1; (Minor) 13.6, 21.8, 31.4, 34.4, 34.9, 35.4,
38.1, 45.69, 62.3, 69.0, 116.8, 117.5, 128.6, 129.8, 132.5, 132.67,
136.6, 137.0; m/z (EI HRMS) 382.16738 (Mϩ, C20H31O3PS
requires 382.174833); m/z (EI LRMS) 382 (Mϩ).
5-(Dimethoxyphosphoryl)-6-thiadec-1-ene 2g. A colourless oil
(Found: C, 49.34; H, 8.93. C11H23O3PS requires C, 49.61; H,
8.70%); νmax/cmϪ1 3484, 3078, 2956, 2852, 2367, 2345, 1846,
1641, 1560, 1458, 1380, 1252, 1183, 1032, 915, 821, 752, 637,
550, 479; δH (400 MHz, CDCl3) 0.92 (3 H, t, J 7.3, CH2CH3),
1.37–1.49 (2 H, m, CH2CH3), 1.53–1.61 (2 H, m, SCH2CH2),
1.62–1.72 (1 H, m, PCHCHH), 1.96–2.07 (1 H, m, PCHCHH),
2-Bromo-4-(2-bromoprop-2-enyl)-5-(dimethoxyphosphoryl)-6-
thiadec-1-ene 2k. A colourless oil (Found: C, 35.96; H, 5.31.
C14H25Br2O3PS requires C, 36.23; H, 5.43%); νmax/cmϪ1 3752,
3484, 2955, 2851, 2346, 1794, 1628, 1508, 1465, 1380, 1298,
1257, 1182, 1136, 1032, 892, 854, 822, 751, 620, 564, 538, 517,
485; δH (400 MHz, CDCl3) 0.92 (3 H, t, J 7.3, CH2CH3), 1.42
(2 H, sex, J 7.4, CH2CH3), 1.55–1.62 (2 H, m, SCH2CH2), 2.34–
2.40 (1 H, m, CHHCHCH2), 2.53–2.58 (1 H, m, CHHCHCH2),
2.65–2.72 (1 H, m, CHCH2CBr), 2.74–2.90 (3 H, m, SCH2,
PCHS), 2.93–3.00 (2 H, m, CHHCHCHH), 3.83 (3 H, d, 3JP-H
10.7, OCH3), 3.87 (3 H, d, 3JP-H 10.7, OCH3), 5.51 (1 H, d, 6JP-H
1.0, CBr᎐CHH), 5.55 (1 H, d, 6J 1.0, CBr᎐CHH), 5.67 (1 H,
2.22–2.31 (1 H, m, CHHCH᎐CH ), 2.38–2.46 (1 H, m, CHH-
᎐
2
CH᎐CH ), 2.63–2.71 (2 H, m, SCH ), 2.74–2.81 (1 H, m,
᎐
2
2
3
PCHS), 3.83 (6 H, d, JP-H 10.5, OCH3), 5.01–5.11 (2 H, m,
CH᎐CH ), 5.72–5.83 (1 H, m, CH᎐CH ); δ (100 MHz, CDCl )
᎐
᎐
2
2
C
3
13.6, 21.9, 28.2, 30.6, 31.3, 32.0, 38.8, 53.5, 53.6, 115.9, 137.1;
m/z (EI LRMS) 266 (Mϩ).
5-(Dimethoxyphosphoryl)-4-prop-2-enyl-6-thiadec-1-ene 2h.
A colourless oil (Found: C, 54.62; H, 8.86. C14H27O3PS requires
C, 54.88; H, 8.88%); νmax/cmϪ1 3484, 3077, 2957, 2367, 1838,
1641, 1442, 1380, 1346, 1256, 1182, 1057, 915, 820, 749, 651,
564, 484; δH (400 MHz, CDCl3) 0.92 (3 H, t, J 7.3, CH2CH3),
1.42 (2 H, sex, J 7.3, CH2CH3), 1.56 (2 H, qui, J 7.3, SCH2CH2),
᎐
᎐
P-H
d, 6JP-H 0.7, CBr᎐CHH), 5.69 (1 H, s, CBr᎐CHH); δ (100 MHz,
᎐
᎐
C
CDCl3) 13.6, 21.9, 31.3, 33.9, 36.1, 41.3, 41.4, 41.8, 53.3, 54.1,
119.5, 132.1, 132.4; m/z (EI LRMS) 464 (Mϩ).
1.95–2.03 (1 H, m, CHHCH᎐CH ), 2.08–2.15 (1 H, m, CH-
᎐
2
CH CH᎐CH ), 2.27–2.31 (2 H, m, CH CH᎐CH ), 2.49–2.55
᎐
᎐
2
2
2
2
(1 H, m, CHHCH᎐CH ), 2.65–2.74 (2 H, m, SCH ), 2.91 (1 H,
᎐
2
2
5-(Diphenylphosphoryl)-4-prop-2-enyl-6-thiadec-1-ene 2l. A
colourless solid; mp 78.5–81.5 ЊC (Found: C, 72.04; H, 7.91.
C24H31OPS requires C, 72.33; H, 7.84%); νmax/cmϪ1 3057, 2958,
2928, 2872, 1638, 1437, 1179, 1118, 1072, 995, 910, 785, 750,
720, 700, 538, 524; δH (400 MHz, CDCl3) 0.74 (3 H, t, J 7.3,
CH2CH3), 1.08–1.29 (4 H, m, CH2CH3, SCH2CH2), 1.87–2.01
2
3
dd, J 2.3, JP-H 17.7, PCHS), 3.82 (3 H, d, JP-H 10.5, OCH3),
3
3.84 (3 H, d, JP-H 10.5, OCH ), 5.02–5.11 (4 H, m, CH᎐CH ),
᎐
3
2
5.66–5.80 (2 H, m, CH᎐CH ); δ (100 MHz, CDCl ) 13.6, 21.8,
᎐
2
C
3
31.3, 33.9, 34.7, 35.1, 38.6, 42.7, 53.2, 53.7, 116.8, 117.3, 136.7,
137.1; m/z (EI LRMS) 306 (Mϩ).
(2 H, m, CH CH᎐CH ), 2.08–2.15 (1 H, m, CHCH CH᎐CH ),
᎐
᎐
2
2
2
2
5-[Methoxy(phenyl)phosphoryl]-4-prop-2-enyl-6-thiadec-1-
ene 2i. A colourless oil; νmax/cmϪ1 3076, 2957, 2930, 2873, 2368,
2346, 1654, 1639, 1591, 1438, 1276, 1236, 1119, 1036, 998, 914,
782, 751, 697, 561, 541, 498; δH (400 MHz, CDCl3) 0.86 (3 H, t,
J 7.1, CH2CH3), 1.13–1.49 (4 H, m, CH2CH3, SCH2CH2), 1.94–
2.21–2.37 (3 H, m, CH CH᎐CH , SCHH), 2.60–2.66 (1 H, m,
᎐
2 2
SCHH), 3.29 (1 H, dd, J 1.8, 2JP-H 8.4, PCHS), 4.88–4.93 (2 H,
m, CH᎐CH ), 5.04–5.17 (2 H, m, CH᎐CH ), 5.52–5.73 (2 H, m,
᎐
᎐
2
2
CH᎐CH ), 7.43–7.55 (6 H, m, Ar), 7.85–8.02 (4 H, m, Ar);
᎐
2
δC (100 MHz, CDCl3) 13.4, 21.6, 31.2, 34.8, 35.4, 35.5, 38.4,
46.7, 116.5, 117.6, 128.2, 128.6, 131.3, 131.6, 131.7, 131.8,
132.80, 132.84, 136.8, 137.4; m/z (EI LRMS) 398 (Mϩ).
2.16 (2 H, m, CH CH᎐CH ), 2.19–2.36 (3 H, m, CHCH CH᎐
᎐
᎐
2
2
2
CH , CH CH᎐CH ), 2.43–2.58 (2 H, m, SCH ), 2.90 (1 H, dd,
᎐
2
2
2
2
J 1.5, 2JP-H 13.2, PCHS), 3.72 (3 H, d, 3JP-H 11.2, OCH3), 4.96–
5.09 (4 H, m, CH᎐CH ), 5.49–5.79 (2 H, m, CH᎐CH ), 7.47–
5-(Dimethoxyphosphoryl)-4-phenyl-6-selenahept-1-ene 2m. A
colourless oil (Found: C, 48.64; H, 6.01. C14H21O3PSe requires
C, 48.42; H, 6.10%); νmax/cmϪ1 3462, 3063, 3029, 3004, 2977,
2952, 2928, 2850, 1640, 1603, 1496, 1455, 1419, 1277, 1244,
1183, 1060, 1032, 914, 846, 818, 775, 758, 742, 702, 664, 594,
᎐
᎐
2
2
7.60 (3 H, m, Ar), 7.81–7.88 (2 H, m, Ar); (Minor) 0.77 (3 H, t,
J 7.1, CH2CH3), 1.13–1.49 (4 H, m, CH2CH3, SCH2CH2), 1.94–
2.16 (2 H, m, CH CH᎐CH ), 2.19–2.36 (3 H, m, CHCH CH᎐
᎐
᎐
2
2
2
CH , CH CH᎐CH ), 2.43–2.58 (2 H, m, SCH ), 2.89 (1 H, dd,
᎐
2
2
2
2
2
J 1.5, 2JP-H 13.7, PCHS), 3.70 (3 H, d, 3JP-H 10.7, OCH3), 4.96–
5.09 (4 H, m, CH᎐CH ), 5.49–5.79 (2 H, m, CH᎐CH ), 7.47–
539; δH (400 MHz, CDCl3) (Major) 2.12 (3 H, s, JSe-H 12.0,
SeCH ), 2.56–2.64 (1 H, m, CHHCH᎐CH ), 2.78–2.86 (1 H, m,
᎐
᎐
᎐
2
2
3
2
7.60 (3 H, m, Ar), 7.81–7.88 (2 H, m, Ar); δC (100 MHz, CDCl3)
(Major) 13.6, 21.8, 31.4, 34.3, 35.1, 35.3, 37.6, 46.0, 51.5, 116.6,
117.3, 128.5, 129.7, 132.4, 132.5, 132.7, 132.8, 136.8, 137.1;
(Minor) 13.5, 21.7, 31.2, 34.1 (SCH2), 34.96, 34.97, 38.0, 45.9,
51.9, 116.6, 117.2, 128.4, 129.9, 132.4, 132.5, 132.7, 132.8,
136.9, 137.3; m/z (EI HRMS) 352.16682 (Mϩ, C19H29O2PS
requires 352.16427); m/z (EI LRMS) 352 (Mϩ).
CHHCH᎐CH ), 3.03 (1 H, dd, J 4.2, 2JP-H 16.3, PCHSe), 3.33–
᎐
2
3
3.40 (1 H, m, PCHCH), 3.57 (3 H, d, JP-H 10.7, OCH3), 3.65
(3 H, d, 3JP-H 10.7, OCH ), 4.89–5.14 (2 H, m, CH᎐CH ), 5.54–
᎐
3
2
5.73 (1 H, m, CH᎐CH ), 7.20–7.37 (5 H, m, Ar); (Minor) 1.81
᎐
2
(3 H, s, 2JSe-H 12.0, SeCH ), 2.66–2.72 (1 H, m, CHHCH᎐CH ),
᎐
3
2
2
2.78–2.86 (1 H, m, CHHCH᎐CH ), 2.86 (1 H, dd, J 4.3, J
᎐
2
P-H
17.4, PCHSe), 3.33–3.40 (1 H, m, PCHCH), 3.72 (3 H, d, 3JP-H
922
J. Chem. Soc., Perkin Trans. 1, 2000, 917–924

View Article Online
10.7, OCH3), 3.79 (3 H, d, 3JP-H 10.7, OCH3), 4.89–5.14 (2 H, m,
CH᎐CH ), 5.54–5.73 (1 H, m, CH᎐CH ), 7.20–7.37 (5 H, m,
Table 6 Crystal data for 2n
᎐
᎐
2
2
Chemical formula
Formula weight
Crystal system
µ(Mo-Kα)
Unit-cell dimensions
Space group
C20H19OPS
385.30
Ar); δC (100 MHz, CDCl3) (Major) 7.5, 38.8, 39.7, 44.5, 53.2,
53.4, 117.5, 127.0, 127.8, 128.7, 136.3, 140.9; (Minor) 7.2, 35.6,
42.8, 44.4, 53.4, 53.8, 116.6, 126.8, 128.2, 128.5, 136.1, 141.5;
Triclinic
22.84 cmϪ1
2
δSe (76.2 MHz, CDCl3) (Major) 74.9 (d, JSe-P 12.2); (Minor)
0.17 × 0.17 × 0.14
77.8 (d, 2JSe-P 18.3); m/z (EI LRMS) 348 (Mϩ).
¯
P1 (#2)
2
Z
a
b
c
α
β
γ
V
9.404(3) Å
16.703(4) Å
5.777(1) Å
96.67(2)
107.37(2)
83.96(2)
857.9(4) Å3
Mo-Kα
Ϫ80.0
0.034
0.036
4194
3951
1-(Diphenylphosphoryl)-1-phenyl-2-selenapropane 2n. A col-
ourless solid; mp 221.5–223.5 ЊC (Found: C, 62.32; H, 4.98.
C20H19OPSe requires C, 62.35; H, 4.97%); νmax/cmϪ1 3057, 2934,
1654, 1560, 1492, 1438, 1262, 1184, 1174, 1120, 1107, 1071,
1027, 796, 718, 698, 600, 533, 519; δH (400 MHz, CDCl3) 1.93
2
2
(3 H, s, JSe-H 12.0, SeCH3), 4.47 (1 H, d, JP-H 5.9, PCHSe),
7.14–7.60 (13 H, m, Ar), 7.90–7.95 (2 H, m, Ar); δC (100 MHz,
CDCl3) 6.2, 40.9, 127.4, 128.1, 128.2, 128.4, 128.5, 129.85,
129.91, 131.2, 131.3, 131.4, 131.5, 131.88, 131.91, 135.8; δSe
Radiation
T/ЊC
R
Rw
Observed reflections
Unique reflections
Rint
2
(76.2 MHz, CDCl3) 238.2 (d, JSe-P 36.6); m/z (EI LRMS) 292
(Mϩ Ϫ SeCH3).
0.026
A procedure for the reaction of 2-prop-2-enylpent-4-ene-
selenothioic acid S-butyl ester 1d with triphenylphosphine
radiation (λ = 0.71069 Å). An X-ray quality crystal of 2n was
obtained by recrystallization from MeOH. A full-matrix least-
squares refinement was executed with non-hydrogen atoms
being anisotropic. The final least-square cycle included fixed
hydrogen atoms at calculated positions of which each isotropic
thermal parameter was set to 1.2 times of that of the connect-
ing atom. Other parameters are summarised in Table 6.
To a solution of 2-prop-2-enylpent-4-eneselenothioic acid
S-butyl ester 1d (0.275 g, 1.0 mmol) in CH3CN (5 mL) was
added triphenylphosphine (0.066 g, 0.25 mmol) at room tem-
perature. After being stirred at this temperature for 20 h, the
resulting mixture was concentrated in vacuo. To the residue
was added hexane, and the mixture was filtered. The filtrate was
concentrated, and the residue was purified by column chromato-
graphy on silica gel using hexane to elute 5 (0.228 g, 83% as a
yellow oil).
Acknowledgements
This work was supported in part by a Grant-in-Aid for
Scientific Research on Priority Areas (No. 11120222) and
by a Grant-in-Aid for Scientific Research (No. 9355032) from
the Ministry of Education, Science, Sports and Culture,
Japan.
A procedure for the reduction of bis[1-(butylthio)-2-prop-2-enyl-
penta-1,4-dienyl] diselenide 4
To
a solution of bis[1-(butylthio)-2-prop-2-enylpenta-1,4-
dienyl] diselenide 5 (1.646 g, 3.0 mmol) in MeOH (30 mL) was
added sodium borohydride (0.340 g, 9.0 mmol) at room tem-
perature. After being stirred at this temperature for 5 min under
nitrogen, the resulting mixture was poured into water, and
extracted with Et2O three times. The organic layer was dried
over Na2SO4 and concentrated in vacuo. The residue was puri-
fied by column chromatography on silica gel using hexane to
elute 1d (1.364 g, 83% as a red violet oil).
References
1 For reviews of selenocarbonyl compounds, see: (a) C. Paulmier,
Selenium Reagents and Intermediates in Organic Synthesis, ed. J. E.
Baldwin, Pergamon Press, New York 1986, p. 58; (b) F. S. Guziec,
Jr., The Chemistry of Organic Selenium and Tellurium Compounds,
ed. S. Patai, Wiley, New York, 1987, vol. 2, p. 215; (c) F. S. Guziec,
Jr., Organoselenium Chemistry, ed. D. Liotta, Wiley-Interscience,
New York, 1987, p. 277; (d) A. Ogawa and N. Sonoda, Compre-
hensive Organic Synthesis, ed. B. M. Trost and I. Fleming, Pergamon
Press, Oxford, 1991, vol. 6, p. 461; (e) Comprehensive Organic
Functional Group Transformations, eds. A. R. Katritzky, O. Meth-
Cohn and C. W. Rees, Pergamon, Oxford, 1995, vol. 3, p. 381; vol. 5,
p. 505, p. 565; ( f ) T. Murai and S. Kato, Sulfur Rep., 1998, 20, 397.
2 (a) M. R. Bryce, Aldrichimica Acta, 1985, 18, 73; (b) J. M. Fabre, S.
Chakroune, L. Giral, A. Gorgues and M. Salle, Synth. Met., 1993,
2073; (c) M. L. Petrov and I. K. Rubtsova, Russ. J. Org. Chem.,
1994, 30, 1065; (d) K. Takimiya, Y. Aso and T. Otsubo, Synth. Met.,
1997, 1891; (e) K. Takimiya, A. Morikami, Y. Aso and T. Otsubo,
Chem. Commun., 1997, 1925; ( f ) K. Takimiya, A. Morikami and
T. Otsubo, Synlett, 1997, 319; (g) K. Takimiya, A. Oharuda,
A. Morikami, Y. Aso and T. Otsubo, Angew. Chem., Int. Ed., 1998,
37, 619; (h) T. Jigami, K. Takimiya and T. Otsubo, J. Org. Chem.,
1998, 63, 8865.
2,3-Dimethyl-2-methylselanyl-3-(dimethoxyphosphoryl)-1,4-
oxathiane 15. To a solution of ethaneselenothioic acid S-
selenoacetoxyethyl ester 1h (0.191 g, 0.66 mmol) in toluene (15
mL) was added trimethyl phosphite (0.47 mL, 3.96 mmol) at
room temperature. After being stirred at 85 ЊC for 10 min, the
resulting mixture was concentrated in vacuo. The residue was
purified by column chromatography on silica gel using hexane
and Et2O to elute 15 (0.089 g, 40% as a yellow oil). A colour-
less liquid (Found: C, 32.30; H, 5.59. C9H19O4PSSe requires C,
32.44; H, 5.75%); νmax/cmϪ1 3483, 2954, 2852, 1736, 1654, 1589,
1449, 1370, 1281, 1187, 1040, 850, 803, 734, 664, 510, 468, 460;
δH (400 MHz, CDCl3) 2.16 (3 H, s, SCCH3), 2.17 (3 H, q, J 1.5,
OCCH3), 2.31 (3 H, q, J 1.5, SeCH3), 2.95 (2 H, t, J 7.2, SCH2),
3
3.78 (6 H, d, JP-H 11.2, OCH3), 4.08 (2 H, q, J 7.3, OCH2);
3 P.-E. Hansen, J. Chem. Soc., Perkin Trans. 1, 1980, 1627.
δC (100 MHz, CDCl3) 5.9, 21.9, 22.9, 31.9, 54.3, 66.4, 123.3,
130.8; δP (161.7 MHz, CDCl3) 1.5; δSe (76.2 MHz, CDCl3)
230.5; m/z (EI LRMS) 334 (Mϩ).
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X-Ray structure analysis†
The measurement was carried out on a Rigaku AFC7R four-
circle diffractometer with graphite-monochromated Mo-Kα
† CCDC reference number 207/393. See http://www.rsc.org/suppdata/
p1/a9/a909469e/ for crystallographic files in .cif format.
J. Chem. Soc., Perkin Trans. 1, 2000, 917–924
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