Oxidation of diphenyl diselenide with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). A new method for the electrophilic phenylselenenylation of alkenes under mild conditions

Article abstract of DOI:10.1055/s-2001-18091

The oxidation of diphenyl diselenide with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) represents a convenient mild method to produce a strongly electrophilic phenylselenium reagent. Clean phenylseleno methoxylations and hydroxylations of alkenes containing different types of functional groups can be effected by working in methanol or in acetonitrile and water, respectively. This new electrophilic reagent can also be employed to promote efficient cyclization reactions of alkenols to tetrahydrofurans or of alkenoic acids to lactones.

Full text of DOI:10.1055/s-2001-18091

LETTER
1767
Oxidation of Diphenyl Diselenide with 2,3-Dichloro-5,6-dicyanobenzoquinone
(DDQ). A New Method for the Electrophilic Phenylselenenylation of Alkenes
under Mild Conditions.
O
xidation of Diphenyl
a
D
iselenidercello Tiecco,* Lorenzo Testaferri, Andrea Temperini, Luana Bagnoli, Francesca Marini, Claudio Santi
Dipartimento di Chimica e Tecnologia del Farmaco, Sezione di Chimica Organica, Università di Perugia, I-06100 Perugia, Italy
Fax +39(075)5855116; E-mail: tiecco@unipg.it
Received 12 July 2001
Among these inorganic oxidizing agents the most effi-
Abstract: The oxidation of diphenyl diselenide with 2,3-dichloro-
cient and versatile is the (NH4)2S2O8, which produces the
5,6-dicyanobenzoquinone (DDQ) represents a convenient mild
strongly electrophilic phenylselenenyl sulfate.13–16 Organ-
method to produce a strongly electrophilic phenylselenium reagent.
Clean phenylseleno methoxylations and hydroxylations of alkenes
ic oxidizing agents, like m-nitrobenzenesulfonyl
containing different types of functional groups can be effected by peroxide17 or iodobenzene diacetate,18 have also been
working in methanol or in acetonitrile and water, respectively. This
used in some cases. The drawback of most of these meth-
new electrophilic reagent can also be employed to promote efficient
ods is that the reaction conditions employed are often not
cyclization reactions of alkenols to tetrahydrofurans or of alkenoic
compatible with sensitive functional groups, which may
acids to lactones.
be present in the starting alkene. Thus, a method to effect
Key words: selenium, electrophilic additions, cyclization reactions
the oxidation of diphenyl diselenide under mild experi-
mental conditions is still desirable. On the basis of its
known behavior,19 we examined the possibility of using
Organoselenium compounds are presently employed in
organic synthesis as very useful and powerful reagents.1–7
In most of the selenium promoted conversions the first
step requires the introduction of a phenylseleno group into
an organic molecule. Among the various methods avail-
able the most efficient and most largely used procedure
consists in the reaction of an electrophilic phenylselenium
reagent 2 with an alkene 1 in the presence of a nucleo-
phile. In this way the alkyl phenyl selenides 3 are formed
as the result of a stereospecific anti-addition reaction
(Scheme 1).
the 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) 4. It
was thus observed that an electron transfer reaction from
the diphenyl diselenide 5 to the DDQ 4 occurred easily
and afforded the strongly electrophilic phenylselenenylat-
ing agent 6 (Scheme 2). The reaction can be carried out in
methanol, in acetonitrile or in a mixture of acetonitrile and
water at 30 °C.
Scheme 1
The use of the commercially available phenylselenenyl
chloride and bromide often gives rise to undesirable pro-
cesses such as incorporation of halide anions and decrease
in regioselectivity. For this purpose new phenylseleneny-
lating agents, which do not contain nucleophilic counteri-
ons have been introduced. Some of them were prepared
from PhSeCl like the N-phenylselenophthalimide8,9 or
generated in situ with silver salts, like the
hexafluorophosphate10 or the triflate.11,12 In other cases
the electrophilic reagent was more conveniently produced
in situ by the oxidation of the diphenyl diselenide with
Scheme 2
Treatment of the diphenyl diselenide with DDQ repre-
sents therefore a new, very simple and convenient method
to produce the electrophilic phenylselenium reagent under
extremely mild experimental conditions. The efficiency
of the method has been tested by studying the phenylsele-
no methoxylation and hydroxylation of different types of
alkenes as well as the selenium promoted cyclization re-
actions of alkenols and alkenoic acids. As indicated in
Scheme 2 the reactions of alkenes 1 in methanol or in ac-
etonitrile and water afforded the -methoxyselenide 7 or
-hydroxyselenide 8, respectively.
several
reagents.
Thus
KNO3,13
CuSO4,13
13
Ce(NH4)2(NO2)6
were all successfully employed.
Synlett 2001, No. 11, 26 10 2001. Article Identifier:
1437-2096,E;2001,0,11,1767,1771,ftx,en;G14401ST.pdf.
© Georg Thieme Verlag Stuttgart · New York
ISSN 0936-5214
The results obtained are summarized in Table 1. Reaction
yields are good in almost every case. In the phenylseleno
methoxylation reactions,20 as already observed with other

1768
M. Tiecco et al.
LETTER
Table 1 Phenylseleno Methoxylation and Hydroxylation of Alk-
enes with PhSeSePh and DDQ in Methanol or in Acetonitrile and Wa-
ter, respectively, at 30 °C.
in good yields. Compounds 8a, 8h and 8i were obtained
as single regioisomers. The reaction was not regiospecific
in the case of 8b. In this case also the reaction was a ste-
reospecific anti-addition. In fact, the reactions of the alk-
enes 1d, 1e and 1g afforded 8d, 8e and 8g, respectively, as
the sole reaction products. The cyclic hemiacetal 8h,
which is obtained in excellent yield as a 2:1 mixture of
two diastereoisomers, is very likely produced from the
initially formed -hydroxy aldehyde.
Entry Alkene 1
-Methoxyselenide 7 or
-Hydroxyselenide 8
Yield (%)a
a
65
90
b
50b
45c
-Hydroxyselenides can be transformed into several valu-
able derivatives and are therefore considered important
intermediates in organic synthesis.1–7,22 It seemed there-
fore interesting to investigate the scope of the present
method and in particular its compatibility with other func-
tional groups present in the starting alkenes.
c
54d
d
98
78
Table 2 summarizes the results obtained from the phe-
nylseleno hydroxylation of alkenes containing a carbonyl,
a cyano, an acetylenic or an acetoxy as a second functional
group. In every case the reaction occurs selectively at the
C,C-double bonds and is not influenced by the presence of
the other functional groups. Reaction yields are good in all
cases. With the two terminal alkenes 1m and 1n the addi-
tion reaction is not regiospecific. In contrast, the -hy-
droxyselenide 8l was obtained as the sole reaction
product.
e
78
f
93
64
g
h
49
Table 2 Conversion of functionalized Alkenes into -Hydroxyse-
lenides.
Entry Alkene 1
-Hydroxyselenide 8
Yield (%)
77
84e
l
i
50f
m
44a
n
o
66a
86
a The yields of the -hydroxyselenides are reported in italic.
b A 32% of the other regioisomer was isolated.
c A 30% of the anti-Markovnikov product was isolated.
d A 8% of the other regioisomer was isolated.
e Isolated as a 2:1 mixture of diastereoisomers.
f Isolated as a 1:1 mixture of diastereoisomers.
p
59
phenylselenenylating agents, the addition is not always re-
giospecific. Products deriving from a clean Markovnikov
orientation were observed in the cases of 7a, 7f and 7h,
whereas a mixture of the two regioisomers was obtained
in the cases of 7b and 7c. As expected, the reactions were
completely stereospecific. Thus, the product of anti-addi-
tion 7d was obtained as the sole reaction product. The for-
mation of product 7h is not unexpected since DDQ is
known to behave as mild and efficient catalyst for the ac-
etalization of carbonyl compounds.21
q
r
68b
80c
a A 17% of the other regioisomer was isolated.
b A 13% of 2-hydroxy-1-[(phenylseleno)methyl]ethyl acetate was ob-
tained.
Similar results were obtained in the phenylseleno hydrox-
ylation of alkenes.20 -Hydroxyselenides 8 were obtained
c Isolated as a 1:1 mixture of diastereoisomers.
Synlett 2001, No. 11, 1767–1771 ISSN 0936-5214 © Thieme Stuttgart · New York

LETTER
Oxidation of Diphenyl Diselenide
1769
The preference for Markovnikov addition observed in the
reaction of the alkenes 1l, 1q and 1r is not surprising since
similar results were observed in the phenylseleno acetox-
ylation of terminal alkenes containing an acyloxy group in
the allylic or homoallylic position.23 The reactions of alk-
enes 1o and 1p proceed with high regio- and stereoselec-
tivity. Remarkably, the reaction of 1p with N-
phenylselenophthalimide in the presence of water was not
regiospecific.24
Table 4 Ring-closure Reactions of unsaturated Acids promoted by
PhSeSePh and DDQ in CH3CN at 30 °C.
Entry Alkenoic acid 11
Lactone 12
Yield (%)
95a
a
b
c
85
63
The new electrophilic phenylselenenylating agent pro-
duced from the oxidation of diphenyl diselenide with
DDQ was then employed to promote ring-closure reac-
tions of alkenes containing internal nucleophiles.25 The
reactions investigated were the cyclizations of alkenols 9
to the cyclic selenoethers 10, and of alkenoic acids 11 to
the lactones 12, in acetonitrile at 30 °C. The results ob-
tained are collected in Table 3 and in Table 4.
d
e
47
90b
Table 3 Ring-closure Reactions of Alkenols promoted by Ph-
SeSePh and DDQ in CH3CN at 30 °C.
a The reaction from the corresponding methyl ester furnished also the
hydroxyphenylselenenylated product in appreciable yield.
b Isolated as a 1:1 mixture of diastereoisomers.
Entry Alkenol 9
Cyclic selenoether 10 Yield (%)
a
86
b
c
70
anti-addition as observed with other phenylselenenylating
agents.1–7
57a,c
In conclusion, the results described in the present paper
indicate that the oxidation of diphenyl diselenide with
DDQ represents a very simple method to produce the
strongly electrophilic phenylselenenylating agent in the
absence of nucleophilic counterions. Reaction conditions
are very mild and allow alkenes containing other function-
al groups to be used as reagents. The examples described
above demonstrate that this new procedure is general and
that it favourably compares with the other methods de-
scribed in the literature.1–7,25
d
e
58b,c
70
Acknowledgement
a Isolated as a 1:1 mixture of diastereoisomers.
b Isolated as a 8:2 mixture of diastereoisomers.
c The ratios were determined by GC-MS.
Financial support from MURST, National Project “Stereoselezione
in Sintesi Organica. Metodologie e Applicazioni”, the University of
Perugia, Progetti di Ateneo, and CNR, Rome is gratefully acknow-
ledged.
The cyclizations of the alkenols 9 proceeded easily and af-
forded the expected five- or six-membered cyclic seleno-
ethers 10 in good yields.26 The formation of compounds
10c and 10d is interesting since these compounds18 have
been recently used for the synthesis of C-glycosides, po-
tential inhibitors27 of carbohydrate processing enzymes as
well as for the synthesis of hydroxylated pyrrolizidines.28
References and Notes
(1) Topics in Current Chemistry: Organoselenium Chemistry;
Wirth, T., Ed.; Springer: Berlin, 2000.
(2) Organoselenium Chemistry - A Pratical Approach; Back, T.
G., Ed.; Oxford: New York, 2000.
(3) Krief, A.; Hevesi, L. Organoselenium Chemistry; Springer:
Berlin, 1988.
(4) Rappoport, Z. The Chemistry of Organic Selenium and
Tellurium Compounds; Wiley: New York, 1987.
(5) Liotta, D. Organoselenium Chemistry; Wiley: New York,
1987.
The results collected in Table 4 show that the cyclizations
of the alkenoic acids 11 in acetonitrile proceed smoothly
in all the cases investigated and afforded the expected -
or -lactones 12 in fairly good yields. The products 12c
and 12d were obtained as single stereoisomers thus con-
firming that the ring-closure reaction is a stereospecific
(6) Paulmier, C. Selenium Reagents and Intermediates in
Organic Synthesis; Pergamon Press: Oxford, 1986.
(7) Clive, D. L. J. Tetrahedron 1978, 34, 1049.
Synlett 2001, No. 11, 1767–1771 ISSN 0936-5214 © Thieme Stuttgart · New York

1770
M. Tiecco et al.
LETTER
(8) Nicolaou, K. C.; Claremon, D. A.; Barnette, W. E.; Seitze, S.
P. J. Am. Chem. Soc. 1979, 101, 3704.
(9) Nicolaou, K. C.; Petasis, N. A.; Claremon, D. A.
Tetrahedron 1985, 41, 4835.
(10) Jackson, W. P.; Ley, S. V.; Whittle, A. J. J. Chem. Soc.,
Chem. Commun. 1980, 1173.
(11) Murata, S.; Suzuki, T. Tetrahedron Lett. 1987, 28, 4297.
(12) Murata, S.; Suzuki, T. Tetrahedron Lett. 1987, 28, 4415.
(13) Tiecco, M.; Testaferri, L.; Tingoli, M.; Chianelli, D.;
Bartoli, D. Tetrahedron Lett. 1988, 44, 2273.
27.1, 21.6; MS m/z (relative intensity): 286 (46), 172 (100),
157 (39), 97 (36), 83 (70), 55 (76), 41 (33). Anal. Calcd for
C13H18O2Se: C, 54.74; H, 6.36. Found: C, 54.88; H, 6.23.
(3R)-7-(RS)-Hydroxy-3,7-dimethyl-6-(phenylseleno)
Octanal (8i): Mixture of two diastereoisomers (1:1). Oil. 1H
NMR : 9.74 (t, 1 H, J = 2.1 Hz), 9.63 (t, 1 H, J = 2.2 Hz),
7.66–7.52 (m, 4 H), 7.33–7.20 (m, 6 H), 3.08 (dd, 1 H,
J = 5.8 and 2.4 Hz), 3.02 (dd, 1 H, J = 5.9 and 2.1 Hz), 2.9–
2.55 (bs, 2 H), 2.5–2.1 (m, 4 H), 2.08–1.2 (m, 10 H), 1.36 (s,
6 H), 1.25 (s, 6 H), 0.95 (d, 6 H, J = 7.3 Hz). 13C NMR :
202.5 (2 C), 133.6 (4 C), 129.3 (2 C), 129.1 (4 C), 127.2 (2
C), 72.8 (2 C), 64.9, 64.8, 51.1, 50.5, 36.2, 35.9, 30.2, 30.0,
28.0, 27.5, 26.9 (2 C), 26.8 (2 C), 20.2, 19.4; MS m/z
(relative intensity): 328 (3), 270 (32), 158 (100), 113 (37), 95
(88), 69 (65), 43 (94). Anal. Calcd for C16H24O2Se: C, 58.71;
H, 7.39. Found: C, 58.84; H, 7.28.
(14) Tiecco, M.; Testaferri, L.; Tingoli, M.; Chianelli, D.;
Bartoli, D. Tetrahedron Lett. 1989, 30, 1471.
(15) Tiecco, M.; Testaferri, L.; Tingoli, M.; Chianelli, D.;
Bartoli, D.; Balducci, R. J. Org. Chem. 1990, 55, 429.
(16) Tiecco, M.; Testaferri, L.; Tingoli, M.; Bagnoli, L.; Marini,
F.; Santi, C.; Temperini, A. Gazz. Chim. It. 1996, 126, 635.
(17) Yoshida, M.; Satoh, N.; Kamigata, N. Chem. Lett. 1989,
1433.
(18) Tingoli, M.; Tiecco, M.; Testaferri, L.; Temperini, A. Synth.
Commun. 1998, 28, 1769.
(19) Becker, H. D.; Turner, A. B. The Chemistry of Quinonoid
Compound, Vol. 2; Patai, S., Ed.; J. Wiley: New York, 1988,
1351.
5-Hydroxy-6-(phenylseleno)hexan-2-one (8l): Oil. 1H
NMR : 7.58–7.42 (m, 2 H), 7.34-7.12 (m, 3H), 3.74-3.6 (m,
1H), 3.07 (dd, 1H, J = 12.6 and 4.5 Hz), 2.90 (dd, 1 H,
J = 12.6 and 7.8 Hz), 3.1–2.85 (bs, 1 H), 2.58 (dd, 1 H,
J = 7.2 and 3.2 Hz), 2.55 (dd, 1 H, J = 7.2 and 3.0 Hz), 2.0–
1.6 (m, 2 H), 2.13 (s, 3 H); 13C NMR : 208.9, 132.6 (2 C),
129.0, 128.8 (2 C), 127.0, 69.3, 39.7, 36.4, 30.0. Anal. Calcd
for C12H16O2Se: C, 53.14; H, 5.95. Found: C, 53.27; H, 5.83.
2-Hydroxy-1-phenyl-3-(phenylseleno) Propyl Acetate
(8r): Mixture of two diastereoisomers (1:1). Oil. 1H NMR :
7.5–7.12 (m, 20 H), 5.78 (d, 1 H, J = 6.4 Hz), 5.3–5.1 (m, 2
H), 4.95 (d, 1 H, J = 4.8 Hz), 4.1–3.92 (m, 1 H), 3.15 (dd, 1
H, J = 13.0 and 5.5 Hz), 3.1–2.7 (m, 3 H), 2.8 (dd, 1 H,
J = 13.0 and 8.0 Hz). 13C NMR : 170.1 (2 C), 136.2 (2 C),
132.6 (2 C), 129.1 (2 C), 128.5 (4 C), 128.4 (4 C), 128.1 (4
C), 127.1 (2 C), 126.9 (2 C), 126.5 (2 C), 77.9, 76.5, 74.2,
72.6, 31.8, 27.6, 21.0, 20.6. MS m/z (relative intensity): 350
(14), 201 (29), 183 (37), 157 (30), 133 (41), 107 (100), 71
(28), 43 (64). Anal. Calcd for C17H18O3Se: C, 58.46; H, 5.19.
Found: C, 58.53; H, 5.28.
(20) All new compounds were fully characterized by MS, 1H and
13C NMR spectroscopy and by combustion analysis. Starting
materials are commercially available or were prepared as
described in the literature. Phenylseleno methoxylation
and hydroxylation of alkenes: General Procedure. To the
solution of the starting alkene (1 mmol), in anhyd MeOH
(15 mL) or in CH3CN and H2O (98:2) (15 mL), diphenyl
diselenide (0.6 mmol)and then DDQ (0.6 mmol) were added
and the mixture was stirred at 30 °C. The initial deep red
color of the solution gradually disappears. The progress of
the reaction was monitored by TLC and GC-MS. Reaction
times ranged from 8 h to 48 h. The reaction mixture was
poured into 10% Na2CO3 solution to eliminate the formed
hydroquinone and extracted with Et2O. The organic layer
was dried (Na2SO4) and evaporated. Chromatography of the
residue through a silica gel column afforded the reaction
products in pure form. Compounds 7a,17 7c,17 7d,14 8a,8 8b,
8d,13 8e,8 8g8 and 8p17 have already been described.
Physical, spectral and analytical data of some selected new
compounds are reported below.
(21) Kjolberg, B.; Neumann, K. Acta Chem. Scand. 1993, 47,
834.
(22) Toshimitsu, A.; Aoai, T.; Uemura, S.; Owada, H.; Okano, M.
Tetrahedron Lett. 1985, 41, 5301.
(23) Engman, L. J. Org. Chem. 1989, 54, 884.
(24) Sweeeney, J. B.; Knight, J. R.; Haughan, A. F. Tetrahedron
Lett. 1994, 35, 1781.
[(2,5,5-Trimethoxy-4,4-dimethylpentyl)seleno] Benzene
(7h): Oil. 1H NMR : 7.61–7.45 (m, 2 H), 7.31–7.16 (m,
3 H), 4.84 (s, 1 H), 3.58–3.4 (m, 1 H), 3.47 (s, 3 H), 3.25 (s,
3 H), 3.12 (dd, 1 H, J = 12.1 and 4.3 Hz), 2.93 (dd, 1 H,
J = 12.1 and 7.1 Hz), 1.67–1.58 (m, 2 H), 0.93 (s, 3 H), 0.91
(s, 3 H). 13C NMR : 132.7 (2 C), 128.8 (2 C), 128.7, 126.7,
113.6, 77.7, 58.2 (2 C), 55.6, 42.0, 38.9, 32.9, 22.9, 22.1. MS
m/z (relative intensity): 346 (17), 175 (23), 143 (71), 111
(29), 75 (100), 47 (12). Anal. Calcd for C16H26O3Se: C,
55.65; H, 7.59. Found: C, 55.77; H, 7.48.
3,3-Dimethyl-5-[(phenylseleno)methyl] tetrahydro-
furan-2-ol (8h): Mixture of two diastereoisomers (2.6:1).
Oil. Major diast. 1H NMR : 7.60–7.45 (m, 2 H), 7.34–7.15
(m, 3 H), 4.9 (s, 1 H), 4.50–4.25 (m, 1 H), 3.82 (bs, 1 H), 3.24
(dd, 1 H, J = 12.2 and 5.7 Hz), 3.02 (dd, 1 H, J = 12.2 and
7.1 Hz), 1.84 (dd, 1 H, J = 12.2 and 6.5 Hz), 1.69 (dd, 1 H,
J = 12.2 and 9.3 Hz), 1.08 (s, 3 H). 13C NMR : 132.5 (2 C),
129.9, 128.9 (2 C), 126.8, 104.2, 78.2, 44.1, 43.1, 35.0, 25.2,
29.1. Minor diast. 1H NMR : 7.60–7.45 (m, 2 H), 7.34–7.15
(m, 3 H), 5.04 (s, 1 H), 4.50–4.25 (m, 1 H), 3.92 (bs, 1 H),
3.12 (dd, 1 H, J = 12.1 and 6.0 Hz), 2.97 (dd, 1 H, J = 12.1
and 7.1 Hz), 2.04 (dd, 1 H, J = 12.6 and 7.7 Hz), 1.5 (dd, 1
H, J = 12.6 and 6.8 Hz), 1.08 (s, 3 H). 13C NMR : 132.5 (2
C), 129.9, 128.9 (2 C), 126.8, 104.6, 76.3, 43.9, 43.1, 33.7,
(25) Tiecco, M. In Topics in Current Chemistry:
Organoselenium Chemistry, Chap. Electrophilic Selenium,
Selenocyclizations; Wirth, T., Ed.; Springer: Berlin, 2000, 7.
(26) Ring-Closure Reactions. General Procedure. A solution of
diphenyl diselenide (0.6 mmol), of DDQ (0.6 mmol) and of
the alkenol or the alkenoic acid (1 mmol) in CH3CN (15 mL)
was stirred at 30 °C. The progress of the reaction was
monitored by TLC and GC-MS, the reaction times ranged
from 8 h to 30 h and during this time the color of the mixture
gradually disappeared. The reaction mixture was poured into
10% Na2CO3 solution and extracted with diethyl ether. The
organic layer was dried (Na2SO4) and evaporated.
Chromatography of the residue through a silica gel column
afforded the reaction products in pure form. Compounds
10a,15 10b,15 10c,18 10d,18 10e,15 12a–c15 have already been
described. Physical, spectral and analytical data of some
selected compounds are reported below. (4RS,5SR)-5-
Phenyl-4-(phenylseleno)dihydrofuran-2(3H)-one(12d):29
Oil. 1H NMR : 7.58–7.42 (m, 2 H), 7.4–7.28 (m, 8 H), 5.35
(d, 1 H, J = 7.3 Hz), 3.73 (dt, 1 H, J = 8.2 and 7.3 Hz), 3.02
(dd, 1 H, J = 17.6 and 8.2 Hz), 2.64 (dd, 1 H, J = 17.6 and
8.2 Hz). 13C NMR : 173.3, 137.0, 135.9 (2 C), 129.4 (2 C),
128.8 (2 C), 128.6 (3 C), 125.7 (2 C), 86.0, 42.1, 35.9. MS
m/z (relative intensity): 318 (20), 184 (100), 161 (21), 105
Synlett 2001, No. 11, 1767–1771 ISSN 0936-5214 © Thieme Stuttgart · New York

LETTER
(48), 77 (38). Anal. Calcd for C16H14O2Se: C, 60.58; H, 4.45.
Oxidation of Diphenyl Diselenide
1771
4.3 Hz), 3.15 (dd, 1 H, J = 13.3 and 4.8 Hz), 3 (dd, 1 H,
J = 13.3 and 7.4 Hz), 2.5 (ddd, 1 H, J = 13.5, 8.4 and 1.7 Hz),
2.37 (ddd, 1 H, J = 13.5, 9.5 and 7.5 Hz). 13C NMR : 173.0,
139.3, 133.3 (2 C), 129.5 (2 C), 129.3 (2 C), 128.3, 128.0,
127.2 (3 C), 77.6, 51.2, 34.3, 31.6. Anal. Calcd for
C17H17NO4SSe: C, 49.76; H, 4.18; N, 3.41. Found: C, 49.78;
H, 4.21; N, 3.38.
Found: C, 60.56; H, 4.46.
N-{2-Oxo-5-[(phenylseleno)methyl]tetrahydrofuran-3-
yl}benzenesulfonamide (12e): Oil. First diastereoisomer.
1H NMR : 7.92–7.8 (m, 2 H), 7.65–7.44 (m, 5 H), 7.35–
7.24 (m, 3 H), 5.56 (d, 1 H, J = 4.5 Hz), 4.5 (ddt, 1 H,
J = 10.1, 7.4 and 5.1 Hz), 4.03 (ddd, 1 H, J = 11.3, 8.3 and
4.5 Hz), 3.27 (dd, 1 H, J = 13.0 and 5.1 Hz), 3.0 (dd, 1 H,
J = 13.0 and 7.4 Hz), 2.0–1.8 (m, 2 H). 13C NMR : 173.5,
139.3, 132.7 (2 C), 129.5 (2 C), 129.3 (2 C), 128.3, 128.0,
127.2 (3 C), 76.8, 52.9, 36.4, 30.7. Second diastereoisomer.
1H NMR : 7.92–7.80 (m, 2 H), 7.65–7.44 (m, 5 H), 7.35–
7.24 (m, 3 H), 5.3 (d, 1 H, J = 4.3 Hz), 4.78 (dddd, 1 H,
J = 7.5, 7.4, 4.8 and 1.7 Hz), 4.2 (ddd, 1 H, J = 9.5, 8.4 and
(27) Cipolla, L.; Lay, L.; Nicotra, F. Carbohydr. Lett. 1996, 2,
131.
(28) Hall, A.; Meldrum, K. P.; Therond, P. R.; Wightman, R. H.
Synlett 1997, 123.
(29) Tiecco, M.; Testaferri, L.; Tingoli, M.; Marini, F. J. Chem.
Soc., Chem. Commun. 1994, 221.
Synlett 2001, No. 11, 1767–1771 ISSN 0936-5214 © Thieme Stuttgart · New York