Moderate generation of sulfenylnitrenes from novel N-sulfenylsulfodiimides

Article abstract of DOI:10.1016/j.tetlet.2006.11.078

N-Sulfenylated sulfodiimides were first prepared by the reaction of S,S-diphenyl-N-tosylsulfodiimide with arenesulfenyl chlorides under the basic conditions. Thermolysis of S,S-diphenyl-N-(2-nitrophenylsulfenyl)- and S,S-diphenyl-N-(2,4-dinitrophenylsulfe

Full text of DOI:10.1016/j.tetlet.2006.11.078

Tetrahedron Letters 48 (2007) 427–430
Moderate generation of sulfenylnitrenes from
novel N-sulfenylsulfodiimides
Toshiaki Yoshimura,a,* Tetsuo Fujiea and Takayoshi Fujiib
aDepartment of Applied Chemistry, Graduate School of Science and Engineering, University of Toyama,
Gofuku, Toyama 930-8555, Japan
bCollege of Industrial Technology, Nihon University, 1-2-1 Izumicho, Narashino, Chiba 275-8575, Japan
Received 5 October 2006; revised 6 November 2006; accepted 10 November 2006
Abstract—N-Sulfenylated sulfodiimides were first prepared by the reaction of S,S-diphenyl-N-tosylsulfodiimide with arenesulfenyl
chlorides under the basic conditions. Thermolysis of S,S-diphenyl-N-(2-nitrophenylsulfenyl)- and S,S-diphenyl-N-(2,4-dini-
trophenylsulfenyl)sulfodiimides in the presence of olefins proceeded at 50–80 °C to give the corresponding deiminated S,S-diphen-
yl-N-tosylsulfimide and N-sulfenylaziridines in very good yields. 2,4-Dinitrophenyl-sulfenylnitrene was trapped by trans- and
cis-1-phenylpropenes stereospecifically. The thermolysis temperature of the N-sulfenylsulfodiimides was found to be lower than
N-sulfenylsulfoximide and higher than N-sulfenyliminosulfonium salt and very effective to trap the sulfenylnitrene to give the N-sulf-
enylaziridines in very good yields.
Ó 2006 Elsevier Ltd. All rights reserved.
1. Introduction
results show that the reactivity of sulfenylnitrene is not
enough high towards olefins at ꢀ30 °C and requires
higher temperature. However, stereospecificity of trap-
ping by the Atkinson’s method3a–d is low. Therefore,
milder thermolytic generation of sulfenylnitrene has
been interesting. On the other side, Furukawa et al.5
reported that the reaction of diphenylsulfoximides with
p-toluenesulfenyl chloride gives the corresponding N-
sulfenylsulfoximide which further undergoes thermolysis
at 140 °C to give the corresponding sulfoxides, though
they have not shown the evidence of the formation of
the sulfenylnitrenes in this thermolysis. This result
shows that the N-sulfenylation of the sulfoximide
activates the S–N bond to reduce the thermolysis
temperature, because the usual sulfoximide does not
decompose up to 300 °C. Meanwhile, there is no
example of N-sulfenylsulfodiimide to date except for
Recently, we reported that N-sulfenylation of triphenyl-
k6-sulfanenitrile1 generates sulfenylnitrenes at ꢀ30 °C to
give the corresponding N-sulfenylaziridines by trapping
with olefins, though the yields of the sulfenylaziridines
are not enough.2 In this reaction cis- and trans-1-phenyl-
propenes afforded the corresponding stereospecific
products, cis- and trans-2-methyl-3-phenyl-N-(2,4-di-
nitrophenylsulfenyl)-aziridines, respectively, though
the cis-olefin gave the aziridine in poor yield. Sulfenyl-
nitrenes are known to be generated by the oxidation
of the corresponding sulfenamides with lead tetra-
acetate3a,b and with NBS.3e But these reactions have a
drawback, that is, the formed sulfenylnitrenes attack
the sulfenamides to lower the yield of the aziridines.
Kaszynski and Young also reported the generation of
propylsulfenylnitrene by thermolysis of 3,6-diphenyl-1-
propanesulfenimido-1,2,4,5-tetrazine, though they did not
trap the nitrene.4 Another method involving thermo-
lysis of N-arylsulfenylimino-1,4-dihydro-naphthalenes3c,d
gives the sulfenylaziridines in very good yields. These
Ts
1) NaH (1.2 eq.)
Ts
N
S
N
S
1
2)
(1.4 eq.)
R S Cl
Ph
Ph
Ph
Ph
CH3CN, - 5 ºC, 10 h
N
N
R1
H
S
2, R1 = 2,4-dinitrophenyl (83%a))
3, R1 = 2-nitrophenyl (59%a)
1
Keywords: Sulfenylnitrene; N-Sulfenylsulfodiimide; k4-Sulfanenitrile;
DFT calculation.
)
(a) Isolated yields
*
Corresponding author. Tel./fax: +81 76 445 6850; e-mail: yosimura@
eng.u-toyama.ac.jp
Scheme 1.
0040-4039/$ - see front matter Ó 2006 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2006.11.078

428
T. Yoshimura et al. / Tetrahedron Letters 48 (2007) 427–430
Table 1. Thermolysis of N-sulfenylated sulfodiimides
2
4
R
R
3
5
1
R
R
Ts
N
Ts
Ph
SR
N
S
alkens (10 eq.)
2
4
N
N
R
R
Ph
S
Ph
Ph
1
S
R
5
3
CH CN, 80 ºC, 1 h
3
R
R
N
1
S
R
aziridines
1
2; R = 2,4-dinitrophenyl
1
3; R = 2-nitrophenyl
Entry
Substrate
Alkenes
None
Products
Products yields (%)
Aziridines (%)
—
Sulfimides
Quant
1
2
2
Unidentified products
1
SR
Me
98a
97a
99a
99a
Quant
Quant
Quant
Quant
N
(trans only)
Ph
Ph
Ph
Ph
Me
1
SR
N
3
4
5
(cis only)
Me
Me
1
SR
N
Ph
Ph
1
SR
Me
Me
Me
N
Me
Me
Me
1
SR
O
N
Ph
6
38b
Quant
Ph
Ph
Ph
O
1
SR
N
Me
7
8
3
85b
Quant
Quant
Quant
Quant
Quant
(trans only)
Ph
Ph
Ph
Ph
Ph
Me
1
SR
N
70b (trans:cis = 64:36)
Me
Me
Me
1
SR
N
9
77b (trans:cis = 99:1)
Ph
Ph
Me
1
SR
N
10
11
90b
Ph
1
SR
Me
Me
Me
65b
N
Me
Me
Me
Ph
1
SR
O
N
Ph
12
60b
Quant
Ph
Ph
O
a Isolated yields.
b 1H NMR yields.

T. Yoshimura et al. / Tetrahedron Letters 48 (2007) 427–430
429
Ts
O
Ts
N
S
O
N
S
Me
S
Me
Ph
Ph
Ph
S
Ph
Ph
Ph
CH3CN, 80 ºC, 1 h
N
N
R1
S
R1
S
2, R1 = 2,4-dinitrophenyl
3, R1 = 2-nitrophenyl
96%a)
85%b)
Quant
Quant
(a) Isolated yield, (b) 1H NMR yield.
Scheme 2.
dimethyl-N-thiocyanosullfodiimide.6 The reaction of
diphenylsulfodiimide with p-toluenesulfenyl chloride is
known to give the reduction products, sulfide and
sulfimide,5 and thus the thermolysis temperature of
some N-sulfenysulfodiimides can be expected to be lower
than that of the sulfoximides. This letter will report that
N-sulfenylsulfodiimides were first isolated and their
thermolysis was carried out in the presence of alkenes.
trophenylsulfenylnitrene was trapped by trans- and cis-
1-phenylpropenes to give the corresponding trans- and
cis-N-sulfenylaziridines, respectively, without any other
isomer (entries 1 and 2). The stereospecificity is very
high inconsistently with that of Atkinson’s results.3a–d
The reason for this conflict is not clear. But 2-nitro-
phenyl-sulfenyl derivative with cis-1-phenylpropene
gave a mixture of cis- and trans-aziridines (entries 7
and 8). Though the reason for this less stereospecificity
is not clear, 10% cis–trans isomerization of the 1-phenyl-
propene was observed after the reaction. The trans-aziri-
dines may be mainly formed by the reaction with the
trans-olefins, because the reaction with 50/50 mixed ole-
fins (cis/trans = 50/50) gave the trans-aziridines exclu-
sively (cis/trans = 1/99) (entry 9). The cis-olefins and
the formed cis-aziridines did not isomerize under these
reaction conditions without 3. Compared to the trap-
ping of 2,4-dinitrophenylsulfenylnitrene, that of 2-nitro-
phenyl-sulfenylnitrene with electron rich alkenes such as
1-phenylpropenes and 2-methyl-2-butene reduced the
yields of the aziridines, but the trapping with electron-
deficient benzalacetophenone gave a better yield than
that for 2,4-dinitro derivative. These electronic effects
suggest that the character of the sulfenylnitrene changes
from the electrophilic one (nitrene) to the less electro-
philic one (k4-sulfanenitrile) as shown in Figure 1. Fur-
thermore, the presence of the alkenes did not affect the
rate of the thermolysis and thus the reaction is not
bimolecular.
S,S-Diphenyl-N-(substituted)-N0-sulfenylsulfodiimides
(2–3)7 were obtained in 50–90% yields by treating the
corresponding sulfodiimides 1 with 2,4-dinitro- or 2-
nitrobenzenesulfenyl chloride8 in the presence of NaH
in anhydrous CH3CN under Ar atmosphere at ꢀ5 °C
(Scheme 1), though the reaction at room temperature
gave a mixture with decomposed product N-tosylsulf-
imide like the results of Furukawa and co-workers.5
The structure of these compounds was assigned based
on the analysis of 1H, 13C NMR, IR spectra and elemen-
tal analysis.9 This is the first examples of N-sulfenylated
sulfodiimides except for N-thiocyanosulfodiimide.6
Thermolysis of N-sulfenylsulfodiimides was carried out
at 80 °C in CH3CN in the presence of various alkenes,
and the sulfenylnitrenes were trapped very efficiently
by olefins to afford N-sulfenylaziridines as shown in
Table 1. The sulfenylnitrenes were also trapped effectively
by DMSO to give the corresponding N-sulfenylsulfoxi-
mides as shown in Scheme 2. The thermolysis tempera-
ture at 80 °C is lower than that of Atkinson’s results.
However this temperature is higher than that of our
previous experimental results and gave the N-sulfenyl-
aziridines in very good yields to show enough activa-
tion of the low reactive sulfenylnitrenes. 2,4-Dini-
Sulfenylnitrenes can be expected to have a character of
k4-sulfanenitriles like examples of thiazyl halide, and
perfluoroalkyl R–S„N as a resonance extreme shown
in Figure 1. Unlike these electrophilic k4-sulfanenitriles,
present aromatic sulfenylnitrenes are considered to
reduce its electrophilicity.
R1
R1
R1
S
N
S
N
S N
The electronic structure of sulfenylnitrenes was investi-
gated by DFT calculation using a model compound
(MeS–N) as shown in Figure 2.10 The SN bond length
λ4-Sulfanenitrile
Sulfenylnitrene
Figure 1. Resonance extreme structure.
sulfenylnitrene
sulfenamide
anti
Me
sulfenylnitrene
Me
λ4-sulfanenitrile
syn
S
H
S
Me
S
S Me
S
Me
N
H
H
N
N
N
N
H
1.717a)
1.741a)
1.510a)
(a) SN bond length (Å)
˚
Figure 2. Calculated SN bond lengths (A) of sulfenamide and sulfenylnitrene at B3LYP/6-31G* level.

430
T. Yoshimura et al. / Tetrahedron Letters 48 (2007) 427–430
˚
8.12 (d, J = 8.8 Hz, 4H), 8.30 (dd, J1 = 9.2 Hz,
J2 = 2.4 Hz, 1H), 8.51 (d, J = 9.2 Hz, 1H), 8.97 (d,
J = 2.4 Hz, 1H); 13C NMR (100 MHz, CDCl3) d 21.3,
120.5, 126.0, 127.0, 127.25, 127.33, 128.3, 128.7, 130.0,
134.2, 138.2, 140.5, 140.8, 142.8, 144.0; IR (KBr) 1343,
1300 cmꢀ1 (O@S@O), 1157, 1110, 1080, 1063 cmꢀ1
(N@S@N), 987 cmꢀ1 (S@N); Anal. Calcd for
C25H20N4O6S3: C, 52.80; H, 3.55; N, 9.85. Found: C,
52.94; H, 3.65; N, 9.65.
of the sulfenylnitrene (MeS–N 1.510 A) was found to be
shorter than that of sulfenamides (MeSNH2 syn:
˚
˚
1.717 A, anti: 1.741 A) to suggest that the electronic
structure of the sulfenylnitrene has a character of k4-sul-
fanenitriles. These results suggest that the lower reactiv-
ity of the present sulfenylnitrenes is due mainly to the
electronic structure of the k4-sulfanenitrile and the char-
acter of the electrophilic nitrene is probably contributed
by the electron withdrawing nitro group.
S,S-diphenyl-N-(2-nitrophenylsulfenyl)-N0-tosylsulfodiimide
3. Mp 98 °C (decomp.); 1H NMR (400 MHz, CDCl3) d
2.24 (s, 3H), 6.90 (d, J = 8.0 Hz, 2H), 7.19 (td,
J1 = 8.0 Hz, J2 = 1.2 Hz, 1H) 7.54–7.65 (m, 9H), 8.13–
8.17 (m, 5H), 8.28 (dd, J1 = 8.0 Hz, J2 = 1.2 Hz, 1H); 13C
NMR (100 MHz, CDCl3) d 21.3, 124.1, 124.9, 125.8,
126.1, 128.3, 128.6, 129.8, 133.76, 133.85, 138.9, 140.6,
141.4, 142.4, 144.0; IR (KBr) 1333, 1300 cmꢀ1 (O@S@O),
1184, 1143, 1083, 1047 cmꢀ1 (N@S@N), 985 cmꢀ1 (S@N).
8. The sulfenylating reagents, 2,4-dinitro- and 2-nitro-
benzenesulfenyl chlorides, used are relatively stable and
commercially available.
2. Summary
We have demonstrated the convenient generation of
sulfenylnitrenes with N-sulfenylsulfodiimides. Further-
more, 2,4-dinitrophenylsulfenylnitrene was trapped by
trans- and cis-1-phenylpropenes stereospecifically.
References and notes
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peek by EI and FAB mass spectrum.
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