Azidosulfonylation of alkenes, dienes, and enynes

Article abstract of DOI:10.1016/j.tet.2008.09.096

The radical mediated azidosulfonylation of various alkenes and alkynes that are able to undergo a rapid radical rearrangement is reported. For instance, treatment of 1,6-dienes or 1-en-6-ynes with benzenesulfonyl azide affords cyclic azidosulfones. High yields are observed when tertiary alkyl radicals are azidated in the last step of the cascade process. The azidosulfonylation of β-pinene involving ring opening of the bicyclic skeleton is also reported.

Full text of DOI:10.1016/j.tet.2008.09.096

Tetrahedron 64 (2008) 11860–11864
Contents lists available at ScienceDirect
Tetrahedron
journal homepage: www.elsevier.com/locate/tet
Azidosulfonylation of alkenes, dienes, and enynes
*
Nathalie Mantrand, Philippe Renaud
University of Berne, Department of Chemistry and Biochemistry, Freiestrasse 3, CH-3012 Berne, Switzerland
a r t i c l e i n f o
a b s t r a c t
Article history:
The radical mediated azidosulfonylation of various alkenes and alkynes that are able to undergo a rapid
radical rearrangement is reported. For instance, treatment of 1,6-dienes or 1-en-6-ynes with benzene-
sulfonyl azide affords cyclic azidosulfones. High yields are observed when tertiary alkyl radicals are
Received 26 September 2008
Accepted 30 September 2008
Available online 8 October 2008
azidated in the last step of the cascade process. The azidosulfonylation of
opening of the bicyclic skeleton is also reported.
b-pinene involving ring
Keywords:
Radical reactions
Sulfonyl radicals
Azides
Ó 2008 Elsevier Ltd. All rights reserved.
Sulfones
Dienes
Enynes
1. Introduction
So far, no examples involving the formation of a C–N bond in the
terminal step has been developed.
Radical reactions represent a unique tool for the ring-closing
and ring-opening reactions.1 Most radical chain reactions are based
on the generation of the starting radicals from alkyl halides and
chalcogenides. A general representation of a 5-exo-trig cyclization
process is depicted in Scheme 1 (Eq. 1). In this example, the radical
Yꢀ abstracts an atom X to generate the radical that undergoes the
cyclization process. For this approach, stannyl radicals (Yꢀ¼R3Snꢀ)
are frequently used due to their unique ability to abstract halogen
and chalcogen atoms. An alternative procedure consists of adding
a radical to alkenes and alkynes to generate the starting radical as
shown in Scheme 1 (Eq. 2). Interestingly, this second approach is
not limited to the use of stannyl radicals and excellent results are
also obtained with thiyl and sulfonyl radicals (Y¼RSꢀ and RSO2ꢀ ) that
are known to add efficiently and rapidly to alkenes.
The free-radical cyclization reaction of 1,6-dienes with thiyl
radicals is well documented and involves in most cases thiols as
reagents2 (for a typical example, see Scheme 2, Eq. 3).3 Sulfonyl
radicals have been used for similar cyclization reactions and, in-
terestingly, they offer the possibility to terminate the chain process
by a variety of C–X (X¼halogen or SeR) and C–C bonds when sul-
fonyl halides, selenides (Scheme 2, Eq. 4),4 and cyanides are used.5
Recently, we reported the use of sulfonyl azides as very efficient
radical traps for secondary and tertiary alkyl radicals.6,7 For in-
stance, sulfonyl azides have been used as a key reagent for the
carbazidation of olefins (Scheme 3, Eq. 5).8 In this process, the
benzenesulfonyl radical resulting from the azidation step is used to
generate an electrophilic carbon centered radical that efficiently
adds to olefins. This takes place via reaction of the sulfonyl radical
with hexabutylditin affording a tin radical that rapidly abstracts the
iodine atom. The azidosulfonylation of the olefin (Scheme 3, Eq. 6)
is a potential side reaction of the carboazidation. However, this
process was never observed, presumably due to the fact that the
addition of the sulfonyl radical is a reversible process9 and the
azidation step is slow. We report here that benzenesulfonyl azide is
a suitable reagent to conduct an azidosulfonylation reaction cou-
pled with a fast cyclization or ring-opening process.
X
Y•
–(X–Y)
5-exo-trig
(1)
(2)
Y
Y•
5-exo-trig
Y
* Corresponding author. Fax: þ41 31 631 34 26.
Scheme 1.
E-mail address: philippe.renaud@ioc.unibe.ch (P. Renaud).
0040-4020/$ – see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2008.09.096

N. Mantrand, P. Renaud / Tetrahedron 64 (2008) 11860–11864
11861
MeO
PhSO2N3
initiator
N
Ph
N
O
MeO
no reaction
no reaction
PhSH, AIBN
82%
Ph
SPh
1
(3)
(4)
O
O
PhSO2N3
initiator
2
SO2Ph
SePh
PhSO2N3 (2 eq)
t-BuN=Nt-Bu (0.5 eq)
SO2Ph
O
PhSO2SePh, AIBN
53%
(7)
O
H
H
sun lamp 300 W
99%
N3
4
3
Scheme 2.
SO2Ph
fast
SO2Ph
via
Scheme 4.
O
O
O
ICH2CO2Et
PhSO2N3
3. Azidosulfonylation of 1,6-dienes
C6H13
OEt
C6H13
(5)
(Bu3Sn)2
The azidosulfonylation was then applied to a series of 1,6-dienes
5–11 (Eq. 8). With these substrates, a fast 5-exo-trig cyclization
t-BuON=NOt-Bu (initiator)
N3
84%
PhSO2• + Bu3SnSnBu3
PhSO2SnBu3 + Bu3Sn•
Table 1
Cyclization of 1,6-dienes via azidosulfonylation
Entry
Substrate
Product
Yield % (dr)
76 (2.7:1)a
N3
MeO2C
MeO2C
SO2Ph
PhSO2N3, initiator
MeO2C
MeO2C
(6)
PhO2S
R
R
1
N3
12
PhSO2• +
PhO2S
R
5
R
MeO2C
MeO2C
SO2Ph
SO2Ph
Scheme 3.
MeO2C
MeO2C
2
3
41 (3:3:1:1)
N3
13
6
2. Azidosulfonylation of alkenes
MeO2C
MeO2C
MeO2C
MeO2C
In a preliminary study, several simple alkenes such as 1-octene
1 and 3,4-dihydro-2H-pyran 2 were treated with benzenesulfonyl
azide in the presence of different radical initiators. However, as
expected from our previous observations during the carboazida-
tion process, no trace of products resulting from the azidosulfo-
nylation was detected. Our hypothesis (vide supra) is that this
absence of reaction is resulting from the reversibility of the
addition of the sulfonyl radical and the slowness of the azidation
step. Indeed, the rate of fragmentation of a 2-tosylated secondary
alkyl radical has been measured to be kfragm¼1.5ꢁ106 sꢂ1 at 20 ꢃC.9
The rate of azidation of a secondary alkyl radical has not been
determined but is expected to be kazidationꢄ104 Mꢂ1 sꢂ1 at 20 ꢃC.10
This incited us to examine a system where the radical adduct is
undergoing a fast radical rearrangement competing with the
d
N3
14
7
SO2Ph
TolO2S
N
TolO2S
N
4
5
89 (1:1)
67 (1:1)
N3
15
8
SO2Ph
O
O
N3
16
9
b
-fragmentation of the sulfonyl radical. Therefore, b-pinene 3 was
examined next since the ring opening of the intermediate cyclo-
butylmethyl radical is known to occur readily.11 Different initiation
methods were tested. An electron rich carbon centered radical,
such as a tertiary alkyl radical, is needed to initiate efficiently the
chain reaction via reaction with the electrophilic benzenesulfonyl
azide. Best results were obtained when the reaction was initiated
with di-tert-butyldiazene upon irradiation with a 300 W sun lamp.
Di-tert-butyldiazene was also chosen for its ease of use and
availability.12 Under these conditions, the reaction is completed
within a few hours. The product 4 resulting from ring opening of
the cyclobutane moiety was obtained in 99% yield (Scheme 4,
Eq. 7) demonstrating that when the reversibility of the initial
addition of the benzenesulfonyl radical is suppressed by a fast and
irreversible (or slowly reversible) process,13 the azidosulfonylation
can take place efficiently.
SO2Ph
O
H
O
H
6
89 (1.2:1)
Me
N3
17
Me
10
SO2Ph
O
H
O
H
7
82 (2:1)
Me
N3
18
11
It is assumed that the major product is the cis isomer.14
a

11862
N. Mantrand, P. Renaud / Tetrahedron 64 (2008) 11860–11864
(kcyclizationꢅ106 sꢂ1 at 20 ꢃC) is expected to lead to cyclic derivatives.
The results are summarized in Table 1. Excellent yields (67–89%) are
obtained with reactions leading to tertiary azides (Table 1, entries 1,
4–7). Secondary azides (entry 2) are formed in moderate yields
(41%) and finally, the formation of primary azides was not ob-
served (entry 3). These results are a consequence of the electro-
philic nature of the radical trap that strongly favors reactions with
the more nucleophilic secondary and tertiary alkyl radicals.7
of CDCl3 (7.27 ppm). The 13C spectra were referred to residual signal
of CDCl3 (77.16 ppm). IR spectra were recorded on Jasco FT-IR 460
plus. Mass spectroscopy (MS) and high resolution mass spectros-
copy (HRMS) analysis were performed on Waters Micromass Auto-
spec Q or Qstar Pulsar.
6.2. Starting materials
The starting diallyl malonates 5, 6, and 7 were obtained by al-
kylation of diethyl allylmalonate with the corresponding allylic
bromide.15 The starting allyl and propargyl ethers 9, 10, 11, and 21
were synthesized by the reaction of the corresponding allylic
alcohols with allyl or propargyl bromide in THF in the presence of
sodium hydride.16 Compounds 817 and 1918 were prepared
according to the literature.
PhSO2N3 (2 eq)
SO2Ph
t-BuN=Nt-Bu (0.5 eq)
X
R2
R1
X
(8)
sun lamp 300 W
R3
R2
R3
N3
12–18
R1
5–11
6.3. General procedure for azidosulfonylation
4. Azidosulfonylation of 1-en-6-ynes
Benzenesulfonyl azide (366 mg, 2.0 mmol) and di-tert-butyl-
diazene (94 mL, 0.5 mmol) were added to a solution of the diene or
The cyclization of the 1-ene-6-ynes 19 and 21 was examined
next (Scheme 5, Eqs. 9 and 10). These substrates afford in excellent
yields (80–89%) the tertiary azides 20 and 22, respectively.
enyne (1.0 mmol) in dry benzene (2 mL). The mixture was irradi-
ated with a 300 W sun lamp for 2–4 h until the starting material
was consumed (TLC monitoring). The solvent was evaporated and
the crude mixture was purified by column chromatography on
silica gel (cyclohexane/EtOAc).
SO2Ph
PhSO2N3 (2 eq)
MeO2C
MeO2C
t-BuN=Nt-Bu (0.5 eq)
MeO2C
MeO2C
(9)
sun lamp 300 W
88%
N3
6.4. (L)-((4-(2-Azidopropan-2-yl)cyclohex-1-enyl)-
methylsulfonyl)benzene (4)
19
20
SO2Ph
PhSO2N3 (2 eq)
According to general procedure, (ꢂ)-
b-pinene (157 ml,
t-BuN=Nt-Bu (0.5 eq)
1.0 mmol) afforded 4 (316 mg, 99%). White solid. Mp¼83–84 ꢃC.
O
H
O
H
(10)
Me
N3
sun lamp 300 W
80%
23
[a
]
ꢂ55.6ꢃ (c 1.1, CHCl3). 1H NMR (400 MHz, CDCl3)
d 7.87 (d,
D
Me
J¼8.3, 2H), 7.70–7.62 (m, 1H), 7.56 (t, J¼7.8, 2H), 5.44 (s, 1H), 3.70 (s,
2H), 2.18 (d, J¼5.5, 2H), 2.11–1.97 (m, 1H), 1.91–1.74 (m, 2H), 1.54–
1.45 (m, 1H), 1.25 (s, 3H), 1.24 (s, 3H), 1.23–1.15 (m, 1H). 13C NMR
22
21
Scheme 5.
(101 MHz, CDCl3)
d 133.79, 132.07, 129.12, 128.59, 126.26, 64.36,
63.84, 42.85, 29.70, 27.32, 24.08, 23.72, 23.48. IR (diamond ATR):
2096 (N3), 1305, 1250, 1141, 1083 cmꢂ1. MS (ESIþ): 342.1 (100,
[MþNa]þ). HRMS calcd for C16H21N3O2NaS 342.1252; found
342.1239.
5. Conclusions
We developed an azidosulfonylation reaction that works effi-
ciently with alkenes that undergo a rapid and irreversible (or
slowly reversible) rearrangement upon radical addition. Ring
opening of a cyclobutylmethyl radical as well as 5-exo-trig cycli-
zations of alkyl and vinyl radicals were shown to meet these cri-
teria. Application of the method for the synthesis of alkaloids is
currently under investigation.
6.5. Diethyl 3-(2-azidopropan-2-yl)-4-(phenylsulfonylmethyl)-
cyclopentane-1,1-dicarboxylate (12)
According to general procedure, compound
5 (268 mg,
1.0 mmol) afforded 12 (343 mg, 76%) as a 2.1:1 mixture of di-
astereomers, which was not separated. Pale yellow oil. 1H NMR
6. Experimental section
6.1. General
(400 MHz, CDCl3) d 7.97–7.91 (m, 3H), 7.72–7.64 (m, 1H), 7.63–7.56
(m, 3H), 4.27–4.11 (m, 6H), 3.74 (d, J¼14.4, 1H), 3.55 (dd, J¼1.8,
14.3, 1H), 3.18 (ddd, J¼11.1, 14.4, 25.7, 1H), 2.78–2.72 (m, 1H), 2.71–
2.64 (m, 1H), 2.52 (dd, J¼8.9, 13.8, 4H), 2.11–1.89 (m, 3H), 1.79 (dt,
J¼8.1, 10.8, 1H), 1.56 (t, J¼11.2, 1H), 1.37 (s, 3H), 1.29 (s, 3H), 1.28–
All reactions were performed under a nitrogen atmosphere in
oven-dried flasks (120 ꢃC) unless otherwise stated. Dry solvents for
reactions were filtered through a column of dry alumina under
a positive pressure of argon. Solvents for flash chromatography
were of technical grade and used without purification. Other
chemicals were obtained from commercial sources and used
without further purifications. The reaction were monitored by TLC
(analytical plates, Merck silica gel 60 F254) and visualized under UV
light and/or stained with a solution of KMnO4 or phosphomolybdic
acid followed by heating. Flash chromatography (FC) was per-
formed using Baker silica gel (0.065–0.200 mm). Melting points
(mp) are not corrected. 1H and 13C NMR spectra were recorded on
Bruker Avance-300 (1H: 300 MHz, 13C: 75.5 MHz) or Bruker DRX-400
(1H: 400 MHz, 13C: 100 MHz) spectrometer. The 1H spectra were
referred to an internal standard (TMS, 0 ppm) or to the residual 1H
1.21 (m, 10H), 1.10 (s, 1H). 13C NMR (101 MHz, CDCl3)
d 172.72,
172.51,140.20,133.89, 133.79, 129.48, 129.46, 128.26, 128.16, 63.05,
62.02, 61.92, 61.84, 61.79, 61.62, 60.99, 59.36, 57.60, 54.87, 53.28,
53.02, 39.46, 38.82, 35.62, 35.08, 34.34, 33.81, 26.99, 26.06, 26.03,
22.33, 14.16, 14.13. IR (diamond ATR): 2978, 2100 (N3), 1722, 1256,
1144, 1085 cmꢂ1. MS (ESIþ): 409.17 (30, [MꢂN3]þ), 424.18 (100),
452.18 (20, [MþH]þ), 474.17 (61, [MþNa]þ). HRMS calcd for
C21H29N3O6NaS 474.1674; found 474.1684.
6.6. Diethyl 3-(1-azidoethyl)-4-(phenylsulfonylmethyl)-
cyclopentane-1,1-dicarboxylate (13)
According to general procedure, compound
6 (254 mg,
1.0 mmol) afforded 13 (180 mg, 41%) as a 3:3:1:1 mixture of four

N. Mantrand, P. Renaud / Tetrahedron 64 (2008) 11860–11864
11863
diastereomers, which was not separated. Pale yellow oil. 1H NMR
(300 MHz, CDCl3) 7.88–7.81 (m, 4H), 7.64–7.56 (m, 2H), 7.55–7.47
2094 (N3), 1447, 1306, 1148, 1085 cmꢂ1. MS (ESIþ): 344.11 (100,
[MþNa]þ). HRMS calcd for C15H19N3O3NaS 344.1044; found
344.1057.
d
(m, 4H), 4.18–4.03 (m, 9H), 3.64–3.52 (m, 1H), 3.20–2.94 (m, 5H),
2.68–1.78 (m, 13H), 1.22–1.13 (m, 13H). 13C NMR (101 MHz, CDCl3)
d
172.36, 172.03, 171.91, 171.84, 171.72, 171.69, 171.35, 171.26, 139.53,
6.10. 4-Azido-4-methyl-3-(phenylsulfonylmethyl)-
octahydrobenzofuran (18)
139.51, 139.41, 139.25, 133.87, 133.85, 133.72, 133.70, 129.41, 129.36,
129.31, 129.26, 127.99, 127.96, 127.92, 61.94, 61.73, 61.67, 61.65,
61.58, 61.56, 61.37, 60.85, 60.28, 59.29, 58.68, 58.61, 58.47, 57.48,
56.89, 56.74, 55.64, 54.75, 49.46, 49.10, 48.66, 46.12, 39.50, 39.42,
39.10, 38.24, 37.68, 37.31, 36.47, 36.40, 36.10, 35.44, 35.36, 35.13,
34.38, 34.06, 18.20, 17.99, 17.82, 17.72, 17.59, 15.22, 13.97, 13.95,
13.77, 12.16. IR (diamond ATR): 2103 (N3), 1724, 1249, 1146,
1085 cmꢂ1. MS (ESIþ): 410.12 (100), 438.15 (57, [MþH]þ), 460.13 (31,
[MþNa]þ). HRMS calcd for C20H27N3O6NaS 460.1518; found
460.1531.
According to general procedure, compound 11 (152 mg,
1.0 mmol) afforded 18 (275 mg, 82%) as
astereomers, which was not separated. Pale yellow oil. 1H NMR
(300 MHz, CDCl3) 7.89–7.81 (m, 3H), 7.65–7.58 (m, 1.5H), 7.57–
a 2:1 mixture di-
d
7.48 (m, 3H), 4.11–3.85 (m, 3H), 3.63 (ddt, J¼4.0, 7.7, 13.0, 2.5H),
3.32–3.21 (m, 1.5H), 3.10 (dd, J¼10.2, 14.0, 0.5H), 2.98–2.74 (m, 1H),
2.68–2.43 (m, 0.5H), 1.94 (dd, J¼4.9, 6.2, 1H), 1.88–1.77 (m, 0.5H),
1.74–1.36 (m, 9H), 1.29 (s, 3H), 1.20 (s, 1.5H), 0.88–0.73 (m, 1H). 13C
NMR (75 MHz, CDCl3)
d 139.16, 139.07, 134.11, 134.05, 129.53,
6.7. 3-(2-Azidopropan-2-yl)-4-(phenylsulfonylmethyl)-1-
tosylpyrrolidine (15)
128.05, 127.99, 77.26, 76.39, 71.66, 70.90, 63.58, 62.74, 61.70, 56.67,
52.20, 49.01, 36.86, 36.81, 34.26, 33.13, 27.78, 25.60, 23.99, 22.49,
18.21. IR (diamond ATR): 2938, 2097(N3), 1447, 1306, 1251, 1143,
According to general procedure, compound
8 (280 mg,
1085 cmꢂ1
358.1208.
. HRMS calcd for C16H21N3O3NaS 358.1201; found
1.0 mmol) afforded 15 (412 mg, 89) as a 1:1 mixture of di-
astereomers, which was not separated. Pale yellow oil. 1H NMR
(300 MHz, CDCl3)
d 7.93–7.84 (m, 2H), 7.84–7.77 (m, 2H), 7.77–7.63
(m, 6H), 7.58 (td, J¼2.6, 7.4, 4H), 7.35 (d, J¼8.1, 4H), 3.71 (d, J¼10.9,
1H), 3.59 (d, J¼14.5,1H), 3.47–2.98 (m, 9H), 2.82 (dd, J¼7.2,10.1,1H),
2.77–2.62 (m,1H), 2.47 (d, J¼10.2,1H), 2.44 (s, 3H), 2.43 (s, 3H), 2.31
(dd, J¼11.1, 14.5, 1H), 2.07 (ddd, J¼4.6, 6.5, 8.7, 1H), 1.92 (dd, J¼6.9,
15.1, 1H), 1.28 (s, 3H), 1.20 (s, 3H), 1.17 (s, 3H), 1.08 (s, 3H). 13C NMR
6.11. (E)-Dimethyl 3-(2-azidopropan-2-yl)-4-
(phenylsulfonylmethylene)cyclopentane-1,1-
dicarboxylate (20)
According to general procedure, compound 19 (238 mg,
1.0 mmol) afforded 20 (371 mg, 88%). Pale yellow oil. 1H NMR
(400 MHz, CDCl3) d 8.02–7.80 (m, 2H), 7.68–7.59 (m, 1H), 7.58–7.48
(75 MHz, CDCl3)
d 144.14, 143.89, 139.43, 139.06, 134.16, 134.07,
133.85, 131.83, 130.01, 129.86, 129.54, 128.02, 128.01, 127.93, 127.48,
62.41, 60.33, 59.92, 53.47, 53.22, 53.12, 52.52, 50.98, 48.50, 46.32,
34.40, 34.25, 26.90, 25.44, 25.15, 22.71, 21.64. IR (diamond ATR):
2971, 2102 (N3), 1144 cmꢂ1. MS (ESIþ): 463.0 (81, [MþH]þ), 480.2
(65), 485.1 (100, [MþNa]þ). HRMS calcd for C21H26N4O4NaS2
485.1293; found 485.1288.
(m, 2H), 6.70 (dt, J¼1.7, 3.3, 1H), 4.02 (ddd, J¼12.0, 13.7, 25.7, 1H),
3.77 (s, 3H), 3.63 (s, 3H), 3.00–2.88 (m, 1H), 2.80 (dd, J¼8.3, 10.5,
1H), 2.53 (ddd, J¼2.1, 8.3, 13.3, 1H), 1.90 (dt, J¼23.1, 46.1, 1H), 1.32 (s,
3H), 1.17 (s, 1H). 13C NMR (101 MHz, CDCl3)
d 171.08, 170.77, 157.53,
141.90, 133.46, 129.37, 127.36, 127.25, 63.39, 58.47, 53.27, 53.20,
52.73, 39.72, 34.82, 25.63, 21.23. IR (diamond ATR): 2954, 2101(N3),
1733, 1446, 1435, 1250, 1145 cmꢂ1. MS (ESIþ): 444.13(23, [MþNa]þ),
422.14 (100, [MþH]þ), 394.13 (88). HRMS calcd for C19H24N3O6S
422.1385; found 422.1377.
6.8. 3-(2-Azidopropan-2-yl)-4-(phenylsulfonylmethyl)-
tetrahydrofuran (16)
According to general procedure, compound
9 (126 mg,
1.0 mmol) afforded 16 (208 mg, 67%) as a 1:1 mixture of di-
astereomers, which was not separated. Brown oil. 1H NMR
6.12. (Z)-4-Azido-4-methyl-3-(phenylsulfonylmethylene)-
hexahydro-2H-cyclopenta[b]furan (22)
(300 MHz, CDCl3)
d 7.96–7.89 (m, 4H), 7.74–7.64 (m, 2H), 7.64–7.54
(m, 4H), 4.05–3.51 (m, 9H), 3.37 (dd, J¼2.9, 14.0, 1H), 3.23–3.09 (m,
2H), 2.87–2.67 (m, 1H), 2.64–2.43 (m, 1H), 2.41–2.26 (m, 1H), 1.93
(dt, J¼6.2, 8.1, 1H), 1.34 (s, 3H), 1.31 (s, 3H), 1.23 (s, 3H), 1.19 (s, 3H).
According to general procedure, compound 21 (136 mg,
1.0 mmol) afforded 22 (255 mg, 80%). Pale yellow oil. 1H NMR
13C NMR (75 MHz, CDCl3)
d 139.86, 139.32, 134.11, 133.97, 129.58,
(400 MHz, CDCl3)
d 7.85–7.81 (m, 2H), 7.52–7.42 (m, 3H), 6.22 (td,
129.56, 128.11, 128.06, 73.56, 73.11, 68.85, 66.93, 62.58, 60.81, 60.28,
54.77, 54.39, 52.23, 36.03, 35.61, 26.91, 26.33, 25.29, 23.16. IR (di-
amond ATR): 2973, 2870, 2099 (N3), 1304, 1143, 1085 cmꢂ1. MS
(ESIþ): 327.2 (69), 332.0 (100, [MþNa]þ). HRMS calcd for
C14H19N3O3NaS 332.1044; found 332.1036.
J¼1.5, 2.5, 1H), 4.95–4.88 (m, 1H), 4.68 (dd, J¼2.5, 17.4, 1H), 4.50–
4.46 (m, 1H), 2.95 (d, J¼5.7, 1H), 2.00–1.76 (m, 4H), 1.15 (s, 3H). 13C
NMR (101 MHz, CDCl3)
d 158.44, 143.11, 133.87, 129.58, 127.35,
123.92, 84.65, 71.65, 71.06, 60.19, 38.42, 30.46, 22.00. IR (diamond
ATR): 2950, 2095 (N3), 1448, 1316, 1151 cmꢂ1. MS (ESIþ): 320.1 (80,
[MþH]þ), 342.1(100, [MþNa]þ). HRMS calcd for C15H17N3O3NaS
342.0888; found 342.0883.
6.9. 4-Azido-4-methyl-3-(phenylsulfonylmethyl)hexahydro-
2H-cyclopenta[b]furan (17)
According to general procedure, compound 10 (138 mg,
1.0 mmol) afforded 17 (286 mg, 89%) as a 1.2:1 mixture of di-
astereomers, which was not separated. Pale yellow oil. 1H NMR
Acknowledgements
We thank the Swiss National Science Foundation (Project
200020-112250) and the University of Bern for funding.
(300 MHz, CDCl3) d 8.01–7.89 (m, 5H), 7.75–7.54 (m, 7H), 4.53–4.41
(m, 2H), 4.29–4.12 (m, 1H), 4.04 (t, J¼8.6, 1H), 3.70–3.57 (m, 2H),
3.38–3.25 (m, 2H), 3.14 (dd, J¼10.5,14.1, 1H), 3.04–2.90 (m, 1H),1.44
Supplementary data
(s, 3H), 1.30 (s, 3H). 13C NMR (75 MHz, CDCl3)
d 139.20, 139.05,
134.22, 134.19, 129.81, 129.66, 128.14, 128.06, 84.24, 84.17, 73.17,
72.71, 72.28, 69.24, 59.02, 58.19, 56.09, 55.31, 40.56, 37.50, 36.06,
35.39, 30.77, 30.18, 21.72, 19.60. IR (diamond ATR): 2943, 2360,
1H and 13C NMR spectra of all azidosulfones. Supplementary
data associated with this article can be found in the online version,
at doi:10.1016/j.tet.2008.09.096.

11864
N. Mantrand, P. Renaud / Tetrahedron 64 (2008) 11860–11864
9. Timokhin, V. I.; Gastaldi, S.; Bertrand, M. P.; Chatgilialoglu, C. J. Org. Chem. 2003,
References and notes
68, 3532–3537.
10. Renaud, P.; Weidner, K., unpublished results.
1. Radicals in Synthesis I and II; Gansa¨uer, A., Ed.; Topics in Current Chemistry;
Springer: Berlin, 2006; Vols. 263 and 264; Radicals in Organic Synthesis; Renaud,
P., Sibi, M. P., Eds.; Wiley-VCH: Weinheim, 2001; Vols. 1–2.
2. Kuehne, M. E.; Damon, R. E. J. Org. Chem. 1977, 42, 1825–1832; Majumdar, K.;
Debnath, P. Tetrahedron 2008, 64, 9799–9820.
11. Ingold, K. U.; Maillard, B.; Walton, J. C. J. Chem. Soc., Perkin Trans. 2 1981, 970–
974; Maillard, B.; Walton, J. C. J. Chem. Soc., Perkin Trans. 2 1985, 443–450.
12. Pryor, W. A.; Tang, F. Y.; Tang, R. H.; Church, D. F. J. Am. Chem. Soc. 1982, 104,
2885–2891.
13. Oldroyd, D. M.; Fisher, G. S.; Goldblatt, L. A. J. Am. Chem. Soc. 1950, 72, 2407–
2410; Kang, Y. H.; Kice, J. L. J. Org. Chem. 1984, 49, 1507–1511.
14. De Riggi, I.; Gastaldi, S.; Surzur, J. M.; Bertrand, M. P.; Virgili, A. J. Org. Chem.
1992, 57, 6118–6125; De Riggi, I.; Nouguier, R.; Surzur, J. M.; Lesueur, C.; Ber-
trand, M.; Jaime, C.; Virgili, A. Bull. Soc. Chim. Fr. 1993, 130, 229–235; Nouguier,
R.; Lesueur, C.; De Riggi, E.; Bertrand, M. P.; Virgili, A. Tetrahedron Lett. 1990, 31,
3541–3544.
15. Necas, D.; Tursky, M.; Kotora, M. J. Am. Chem. Soc. 2004, 126, 10222–
10223.
16. Ghosh, S.; Raychaudhuri, S. R.; Salomon, R. G. J. Org. Chem. 1987, 52, 83–90;
Ovaa, H.; Stapper, C.; van der Marel, G. A.; Overkleeft, H. S.; van Boom, J. H.;
Blechert, S. Tetrahedron 2002, 58, 7503–7518.
3. Miyata, O.; Nishiguchi, A.; Ninomiya, I.; Aoe, K.; Okamura, K.; Naito, T. J. Org.
Chem. 2000, 65, 6922–6931.
4. Brumwell, J. E.; Simpkins, N. S.; Terrett, N. K. Tetrahedron 1994, 50, 13533–13552.
5. Bertrand, M. P. Org. Prep. Proced. Int. 1994, 26, 257–290; Bertrand, M. P.; Ferreri,
C. Sulfur-centered Radicals. In Radicals in Organic Synthesis; Renaud, P., Sibi, M. P.,
Eds.; Wiley-VCH: Weinheim, 2001; Vol. 2, pp 485–504; Chatgilialoglu, C. In The
Chemistry of Sulfones and Sulfoxides; Patai, S., Rappoport, Z., Stirling, C. J. M.,
Eds.; John Wiley & Sons: Chichester, UK, 1988; pp 1089–1113; Chatgilialoglu,
C.; Bertrand, M. P.; Ferreri, C. In S-centered Radicals; Alfassi, Z. B., Ed.; Wiley:
Chichester, UK, 1999; pp 311–354.
6. Nyfeler, E.; Renaud, P. Org. Lett. 2008, 10, 985–988; Ollivier, C.; Renaud, P. J. Am.
Chem. Soc. 2000, 122, 6496–6497; Panchaud, P.; Chabaud, L.; Landais, Y.;
Ollivier, C.; Renaud, P.; Zigmantas, S. Chem.dEur. J. 2004, 10, 3606–3614.
7. Ollivier, C.; Renaud, P. J. Am. Chem. Soc. 2001, 123, 4717–4727.
8. Renaud, P.; Ollivier, C.; Panchaud, P. Angew. Chem., Int. Ed. 2002, 41, 3460–3462;
Scha¨r, P.; Renaud, P. Org. Lett. 2006, 8, 1569–1571.
17. Feducia, J. A.; Campbell, A. N.; Doherty, M. Q.; Gagne´, M. R. J. Am. Chem. Soc.
2006, 128, 13290–13297.
18. Munoz, M. P.; Mendez, M.; Nevado, C.; Cardenas, D. J.; Echavarren, A. M. Syn-
thesis 2003, 2898–2902.