Light-induced ruthenium-catalyzed nitrene transfer reactions: A photochemical approach towards N-Acyl sulfimides and sulfoximines

Article abstract of DOI:10.1002/anie.201310790

1,4,2-Dioxazol-5-ones are five-membered heterocycles known to decarboxylate under thermal or photochemical conditions, thus yielding N-acyl nitrenes. Described herein is a light-induced ruthenium-catalyzed N-acyl nitrene transfer to sulfides and sulfoxides by decarboxylation of 1,4,2-dioxazol-5-ones at room temperature, thus providing direct access to N-acyl sulfimides and sulfoximines under mild reaction conditions. In addition, a one-pot sulfur imidation/oxidation sequence catalyzed by a single ruthenium complex is reported. Double duty: A one-pot sulfur imidation/oxidation sequence using a single ruthenium complex for both steps was developed (see scheme). Photochemical decarboxylations of 1,4,2-dioxazol-5-ones provide N-acyl nitrenes, which imidate sulfides at ambient temperature. The subsequent oxidation then occurs under mild phase-transfer catalysis conditions. In this manner, N-acyl sulfimides and sulfoximines can be obtained in high yields starting from sulfides.

Full text of DOI:10.1002/anie.201310790

Angewandte
Chemie
DOI: 10.1002/anie.201310790
Synthetic Methods
Light-Induced Ruthenium-Catalyzed Nitrene Transfer Reactions:
A Photochemical Approach towards N-Acyl Sulfimides and
Sulfoximines**
Vincent Bizet, Laura Buglioni, and Carsten Bolm*
Abstract: 1,4,2-Dioxazol-5-ones are five-membered hetero-
cycles known to decarboxylate under thermal or photochem-
ical conditions, thus yielding N-acyl nitrenes. Described herein
is a light-induced ruthenium-catalyzed N-acyl nitrene transfer
to sulfides and sulfoxides by decarboxylation of 1,4,2-dioxa-
zol-5-ones at room temperature, thus providing direct access to
N-acyl sulfimides and sulfoximines under mild reaction
conditions. In addition, a one-pot sulfur imidation/oxidation
sequence catalyzed by a single ruthenium complex is reported.
O
ver the last fifty years, various methods for the synthesis
of sulfimides and sulfoximines have been reported.[1,2] Some
of those products showed relevant biological properties in
crop protection[3] and medicinal chemistry.[4] Our interest has
been focused on the application of such sulfur reagents in
asymmetric catalysis.[5] For most synthetic approaches
towards sulfimides and sulfoximines, sulfur imidations of
sulfides and sulfoxides, respectively, are key transformations,
and consequently several protocols have been developed.[6–13]
However, only few such methods give direct access to N-
acylated derivatives, which are synthetically valuable because
of the ease of subsequent N functionalization. An early
example stems from Swern and co-workers, who prepared N-
acyl sulfimides by reaction of sulfides with N-bromoacet-
amides and subsequent treatment of the resulting N-acetyl-
imino sulfonium bromides with base.[7] Other methods
involve the use of imidation reagents such as N-phenyl-
Scheme 1. Reactivity of 1,4,2-dioxazol-5-ones (1).
N-acyl nitrenes (2), which rearranged to the isocyanates 3. An
important stimulus for our research was the observation that
the N-acyl sulfoximines 4 were formed when the reactions
were performed in DMSO at 1508C. Although the yields of 4
were mostly moderate, we hypothesized that improvements
were possible by applying a combination of photoinitiation
and metal catalysis.[14] Herein we report on the success of this
approach and the development of sulfoxide and sulfide
imidations which proceed by the photolysis of 1 in the
presence of a ruthenium catalyst, thus providing the N-acyl
sulfoximines 6 and N-acyl sulfimides 8 at room temperature.
The study was initiated by a catalyst screening with 3-
phenyl-1,4,2-dioxazol-5-one (1a) and methylphenylsulfoxide
(5a) as starting materials. The results are summarized in
Table 1. By applying slightly modified reaction conditions,
relative to those described by He and co-workers,[14] using
[Ru(TPP)CO][15] in toluene at 508C for 18 hours, success was
achieved. The desired N-benzoyl sulfoximine 6aa was indeed
formed, albeit in only low yield (37%). The major product
was N,N’-diphenyl urea (9a), which resulted from a hydrolytic
process of the intermediate phenyl isocyanate (3a). Photo-
chemical activation of the catalysis allowed lowering of the
reaction temperature (from 508C to RT) and shortening of
the reaction time (from 18 h to 6 h), but unfortunately, also
under those reaction conditions, the undesired 9a remained
the major product (Table 1, entry 2). Realizing that water
played a prominent role in the formation of 9a, the catalysis
was next performed under inert conditions using dry toluene
as the solvent. To our delight, 6aa was now the exclusive
product, and was isolated in 99% yield after 4 hours at
iodonio
carboxamide
tosylates,[8]
N,O-bis(trifluoro-
catalytic
acetyl)hydroxylamine in combination with
a
amount of a copper(II) salt,[9] nitridomanganese(V) com-
plexes with trifluoroacetic anhydride,[10] and trifluoroaceta-
mide in the presence of a catalytic amount of a rhodium(II)
complex.[11] Mechanistically, they appear to proceed via N-
acyl nitrenes or the corresponding (metal)nitrenoids.
An interesting alternative N-acyl nitrene formation was
reported by Sauer and Mayer, who studied the reactivity of 3-
substituted-1,4,2-dioxazol-5-ones (1; Scheme 1).[12] They
found that these heterocycles decarboxylated under thermal
or photochemical conditions, thus generating highly reactive
[*] Dr. V. Bizet, L. Buglioni, Prof. Dr. C. Bolm
Institute of Organic Chemistry, RWTH Aachen University
Landoltweg 1, 52056 Aachen (Germany)
E-mail: Carsten.Bolm@oc.RWTH-Aachen.de
Homepage: http://bolm.oc.rwth-aachen.de/
[**] V. B. acknowledges the Alexander von Humboldt foundation for
a postdoctoral fellowship.
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/anie.201310790.
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Table 1: Optimization of the reaction conditions.
Table 2: Imidations of 5a and 7a with various 1,4,2-dioxazol-5-ones
(1).[a]
Entry Catalyst
Solv.[a]
T
t [h] hn Yield [%]
6aa 9a
1
2
3
4
[Ru(TPP)CO]
tol[b]
tol[b]
tol
tol
tol
tol
tol
tol
508C 18
À
+
+
+
À
À
À
+
+
+
+
+
+
+
+
+
37
45
99
0
0
42
3
2
9
0
0
61
54
0
0
0
9
11
0
0
0
0
0
0
75
0
Entry
1
R
6
8
[Ru(TPP)CO]
[Ru(TPP)CO]
–
[Ru(TPP)CO]
[Ru(TPP)CO]
[Ru(TPP)CO]
[Ru(TMP)CO]
[Ru(F20-TPP)CO] tol
[Rh2(OAc)4]
[Rh2(OAc)4]
[RuCl2(p-Cym)]2
[RuCl2(p-Cym)]2
[Ru(TPP)CO]
[Ru(TPP)CO]
[Ru(TPP)CO]
RT
RT
RT
RT
6
4
4
18
Yield [%]
Yield [%]
1
2
3
4
5
6
7
1a
1b
1c
1d
Ph
Me
Bn
tBu
CF3
pMeOC6H4
pNO2C6H4
99 (6aa)
95 (6ba)
7 (6ca)[b]
0 (6da)[c]
0 (6ea)[c]
35 (6 fa)
62 (6ga)
99 (8aa)
98 (8ba)
86 (8ca)
0 (8da)[c]
54 (8ea)
99 (8 fa)
72 (8ga)
5[c]
6
508C 18
508C 18
7[c]
8
1e
RT
RT
RT
RT
RT
RT
RT
RT
4
4
4
4
4
4
4
6
6
1 f[d]
1g[e]
9
10
11
12
13
14
15
16
tol
CH2Cl2
[a] Reaction were conducted until full consumption of 1. [b] The
sulfoximine was obtained in a mixture with the corresponding urea.
[c] Decomposition of 1 was observed. [d] Use of 3 mL of toluene instead
of 1 mL. [e] Use of 2 mL of toluene instead of 1 mL.
tol[d]
5
CH2Cl2
CH2Cl2
THF
31
21
0
MeCN[d] RT
0
0
iminations providing the N-acyl sulfoximine 6ca and N-acyl
sulfimide 8ca. Whereas the former was only obtained in
a very low quantity [< 7%, as an inseparable mixture with
N,N’-dibenzylurea (9c)], the latter was isolated in 86% yield
(Table 2, entry 3). The conversions of 5a and 7a with 3-
trifluoromethyl-substituted 1,4,2-dioxazol-5-one (1e; Table 2,
entry 5) were limited by the sensitivity of the iminating agent
towards traces of water, and an undesired deoxygenation of
5a, thus forming sulfide 7a. As a result, 5a could not be
iminated, and the sulfimide 8ea was obtained from 7a in only
moderate yield (54%).
Encouraged by the high reactivity and pronounced
selectivity in the imidations of 7a with various 1,4,2-dioxa-
zol-5-ones (1), respective transformations of diversely sub-
stituted sulfides were investigated next. The results are shown
in Scheme 2. In general, the positive data obtained in the
conversions of 7a were reflected in this study. Thus, sulfides
with an alkyl/alkyl substitution pattern reacted equally well
with 1a, thus providing the corresponding products (8ab, 8ac,
and 8ad) in yields ranging from 82 to 99%. Only the
imidations of diphenylsulfide (7e) and phenylvinyl sulfide
(7 f) with 1a proved more difficult, thus leading to the
corresponding sulfimides (8ae and 8af) in yields of 46 and
63%, respectively. Further improvements were observed
when 1b was used as imidating agent, thus providing
sulfimides 8ba–bi. Now, the yields were generally high (82–
99%) irrespective of the substitution pattern of the sulfide.
Noteworthy also is that sulfides with bromo, nitro, and
methoxy substituents in the para position of the S-aryl group
reacted well, thus providing the corresponding N-acyl sulf-
imides 8bg–bi in high yields. As expected from the initial
study with 7a (Table 2), the other 1,4,2-dioxazol-5-ones (1c,
1e–1g) could be used to deliver the N-acylated sulfimides
8ca–gb in moderate to high yields (43–99%).
[a] Unless noted otherwise, dry solvents were used; tol=toluene.
[b] Non-distilled solvent. [c] The reaction was carried out in the dark.
[d] The catalyst was poorly soluble in this solvent.
ambient temperature (Table 1, entry 3). Additional experi-
ments revealed that the presence of both [Ru(TPP)CO] and
light were essential for promoting the reaction at room
temperature (Table 1, entries 4 and 5). Under thermal con-
ditions using dry toluene as the solvent, 6aa was obtained in
42% yield (Table 1, entry 6). Performing the reaction in the
dark at 508C led to 6aa in only 3% yield (Table 1, entry 7),
thus highlighting the importance of the photochemical
activation in this process. We assume that the light provides
the essential energy for the formation of a reactive rutheno N-
acyl nitrene intermediate without reaching the higher level of
energy required for the Curtius rearrangement which leads to
isocyanates.[16] Other ruthenium porphyrin catalysts such as
[Ru(TMP)CO] and [Ru(F20TPP)CO], as well as [RuCl2(p-
Cym)]2 and [Rh2(OAc)4] were less efficient or ineffective
(Table 1, entries 8–13).[15,17] In terms of solvents, toluene
proved to be superior over CH2Cl2, THF, or acetonitrile
(Table 1, entry 3 versus entries 14–16).
An initial test reaction showed that 1a reacted equally
well with the sulfide 7a, just as it did with the sulfoxide 5a,
under the photocatalytic conditions with [Ru(TPP)CO] to
give 8aa in 99% yield (Table 2, entry 1). Hence, the
subsequent evaluation of the substrate scope involved both
of these starting materials, which were explored in their
reactivity with a range of 1,4,2-dioxazol-5-ones (1). With the
exception of the 3-tert-butyl-substituted derivative 1d
(Table 2, entry 4), which proved to be unstable under the
reaction conditions, all the 1,4,2-dioxazol-5-ones 1 showed
a pronounced N-acyl nitrene transfer ability, thus providing
the corresponding N-acylated sulfoximines 6 and sulfimides 8
in yields of up to 99%. In general, 5a was less reactive than
sulfide 7a, as examplified by the comparison of the respective
Motivated by the positive results of the aforementioned
photochemically-induced ruthenium-catalyzed imidation of
sulfides (Scheme 2), we wondered about the possibility to
2
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Scheme 3. Scope of the one-pot imidation/oxidation reaction.
sufide were well tolerated, and the desired products 6 were
obtained in good to excellent yields (71–99%).
To the best of our knowledge, this direct catalytic
imidation/oxidation sequence has no precedence in the
literature. With a single metal complex two very distinct
substrate oxidations are achieved. While the first step
requires a mild photochemical activation of 3-substituted
1,4,2-dioxazol-5-ones, the second makes use of a simple
inorganic oxidant under phase-transfer catalysis. Overall,
a variety of sulfides can directly be converted in one pot into
synthetically valuable N-protected sulfoximines. Mechanistic
investigations and further attempts to expand the substrate
scope are currently ongoing in our laboratories.
Scheme 2. Scope of the sulfide imidation.
directly prepare the corresponding synthetically highly
appreciated N-protected sulfoximines by introducing a sub-
sequent one-pot metal-catalyzed sulfimide oxidation.[18] We
hypothesized that this second step could then take advantage
of the ruthenium complex already present in the medium. In
fact, [Ru(TPP)CO] was known to react with an oxidant to
give [Ru(TPP)O2], which was capable of oxidizing sul-
fides.[19,20] To evaluate the potential of the oxidation step
following this strategy, 8aa was treated with a mixture of
1 mol% of [Ru(TPP)CO] and 2 equivalents of NaIO4. In the
first attempt, toluene was chosen as solvent because it proved
essential for the first step (imide formation). Unfortunately,
however, even after 72 hours the yield of 6aa was only 9% (in
combination with traces of methyl phenyl sulfone detected by
NMR spectroscopy; 79% of 8aa were re-isolated). To
increase the solubility of the oxidant in the reaction mixture,
water was added (toluene/water= 2:1), and to our delight,
under the biphasic conditions the yield of 6aa increased to
77% (with traces of sulfone; 20% of re-isolated 8aa). Finally,
the best reaction conditions were obtained with a 2:1 mixture
of CH2Cl2 and water for the ruthenium-catalyzed oxidation of
8aa with NaIO4, thus affording 6aa in 99% yield after only
4 hours at room temperature. This result paved the path for
the intended one-pot imidation/oxidation protocol leading to
N-acyl sulfoximines starting from sulfides (Scheme 3). All
substitution patterns (dialkyl, alkyl/aryl, and diaryl) on the
Experimental Section
General procedure for the sequential one-pot imidation/oxidation:
[Ru(TPP)CO] (1.9 mg, 0.0025 mmol) was added to a solution of
sulfide 7 (0.25 mmol) and 1,4,2-dioxazol-5-one 1 (0.25 mmol) in dry
toluene (1 mL) under argon. The reaction mixture was irradiated with
a 125 W high-pressure mercury lamp at room temperature until full
conversion was reached (as analyzed by TLC). The mixture was
concentrated under reduced pressure to remove toluene and then
dissolved in dichloromethane (2.5 mL). A solution of sodium period-
ate (107 mg, 0.5 mmol) in water (1.25 mL) was added and rigorous
stirring of the reaction mixture was performed using a magnetic cross-
shaped stir bar. After full conversion (one night at room temper-
ature), the mixture was extracted with dichloromethane, dried over
sodium sulfate, and concentrated under reduced pressure. The
product was then purified by column chromatography over silica
gel (pentane/AcOEt) to give the corresponding N-acyl sulfoximine 6.
Received: December 12, 2013
Revised: February 17, 2014
Published online: && &&, &&&&
Keywords: homogeneous catalysis · nitrenes · photochemistry ·
.
ruthenium · synthetic methods
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[9] C. S. Tomooka, D. D. LeCloux, H. Sasaki, E. M. Carreira, Org.
Lett. 1999, 1, 149 – 152.
[10] C. S. Tomooka, E. M. Carreira, Helv. Chim. Acta 2002, 85, 3773 –
3784.
[1] For reviews on sulfilimines, see: a) T. L. Gilchrist, C. J. Moody,
Chem. Rev. 1977, 77, 409 – 435; b) N. Furukawa, S. Oae, Ind. Eng.
Chem. Prod. Res. Dev. 1981, 20, 260 – 270; c) I. V. Koval, Sulfur
Rep. 1993, 14, 149; d) P. C. Taylor, Sulfur Rep. 1999, 21, 241 – 280.
[2] For reviews on sulfoximines, see: a) C. R. Johnson, Acc. Chem.
Res. 1973, 6, 341 – 347; b) M. Reggelin, C. Zur, Synthesis 2000, 1 –
64; c) M. Harmata, Chemtracts 2003, 16, 660 – 666; d) H.
Okamura, C. Bolm, Chem. Lett. 2004, 33, 482 – 487; e) C.
Worch, A. C. Mayer, C. Bolm in Organosulfur Chemistry in
Asymmetric Synthesis (Eds.: T. Toru, C. Bolm), Wiley-VCH,
Weinheim, 2008, pp. 209 – 232; f) R. Bentley, Chem. Soc. Rev.
2005, 34, 609 – 624; g) H.-J. Gais, Heteroat. Chem. 2007, 18, 472 –
481.
[3] For selected recent examples, see: a) H. Yu, Z. Qin, H. Dai, X.
Zhang, X. Qin, T. Wang, J. Fang, J. Agric. Food Chem. 2008, 56,
11356 – 11360; b) Y. Zhu, M. R. Loso, G. B. Watson, T. C. Sparks,
R. B. Rogers, J. X. Huang, B. C. Gerwick, J. M. Babcock, D.
Kelley, V. B. Hegde, B. M. Nugent, J. M. Renga, I. Denholm, K.
Gorman, G. J. DeBoer, J. Hasler, T. Meade, J. D. Thomas, J.
Agric. Food Chem. 2011, 59, 2950 – 2957.
[4] For selected recent examples, see: a) D. P. Walker, M. P.
Zawistoski, M. A. McGlynn, J. C. Li, D. W. Kung, P. C. Bonnette,
A. Baumann, L. Buckbinder, J. A. Houser, J. Boer, A. Mistry, S.
Han, L. Xing, A. Guzman-Perez, Bioorg. Med. Chem. Lett. 2009,
19, 3253 – 3258; b) S. J. Park, H. Baars, S. Mersmann, H.
Buschmann, J. M. Baron, P. M. Amann, K. Czaja, H. Hollert,
K. Bluhm, R. Redelstein, C. Bolm, ChemMedChem 2013, 8,
217 – 220; c) U. Lꢀcking, Angew. Chem. 2013, 125, 9570 – 9580;
Angew. Chem. Int. Ed. 2013, 52, 9399 – 9408.
[5] For recent examples, see: a) M. Frings, C. Bolm, Eur. J. Org.
Chem. 2009, 4085 – 4090; b) M. Frings, I. Atodiresei, Y. Wang, J.
Runsink, G. Raabe, C. Bolm, Chem. Eur. J. 2010, 16, 4577 – 4587;
c) M. Frings, I. Thomꢁ, C. Bolm, Beilstein J. Org. Chem. 2012, 8,
1443 – 1451; d) M. Frings, I. Thomꢁ, I. Schiffers, C. Bolm, Chem.
Eur. J. 2014, 20, 1691 – 1700.
[11] H. Okamura, C. Bolm, Org. Lett. 2004, 6, 1305 – 1307.
[12] J. Sauer, K. K. Mayer, Tetrahedron Lett. 1968, 9, 319 – 324.
[13] For selected examples covering conversions of sulfoxide into
sulfimides, see: a) A. K. Sharma, T. Ku, A. D. Dawson, D. Swern,
J. Org. Chem. 1975, 40, 2758 – 2764; b) S. L. Huang, D. Swern, J.
Org. Chem. 1978, 43, 4537 – 4538; c) C. Urban, Y. Macꢁ, F.
Cadoret, J.-C. Blazejewski, E. Magnier, Adv. Synth. Catal. 2010,
352, 2805 – 2814; d) C. M. M. Hendriks, P. Lamers, J. Engel, C.
Bolm, Adv. Synth. Catal. 2013, 355, 3363 – 3368.
[14] For the synthesis of oxazoles and oxazolines by the reaction of 3-
aryl-1,4,2-dioxazol-5-ones with alkynes or alkenes, respectively,
in the presence of [Ru(TTP)CO] (2 mol%), CuCl2 (30 mol%),
and I2 (30 mol%) at 508C to 808C, see: C. L. Zhong, B. Y. Tang,
P. Yin, Y. Chen, L. He, J. Org. Chem. 2012, 77, 4271 – 4277.
(TTP = tetra-p-tolylprophyrinato).
[15] TPP = tetraphenylporphyrinato, TMP = tetramesitylporphyri-
nato, F20TPP = tetra(pentafluorophenyl)porphyrinato.
[16] For recent examples describing the formation of ruthenium
nitrene intermediates starting from ruthenium porphyrin com-
plexes, see: a) S. Fantauzzi, E. Gallo, A. Caselli, F. Ragaini, N.
Casati, P. Macchi, S. Cenini, Chem. Commun. 2009, 3952 – 3954;
b) D. Intrieri, A. Caselli, F. Ragaini, P. Macchi, N. Casati, E.
Gallo, Eur. J. Inorg. Chem. 2012, 569 – 580; c) W. Xiao, C.-Y.
Zhou, C.-M. Che, Chem. Commun. 2012, 48, 5871 – 5873; d) G.
Manca, E. Gallo, D. Intrieri, C. Mealli, ACS Catal. 2014, 4, 823 –
832; e) J. Wei, W. Xiao, C.-Y. Zhou, C.-M. Che, Chem. Commun.
2014, 50, 3373 – 3376.
[17] For selected examples of reports describing nitrene-transfer
reactions with metallo salen catalysts, see: a) H. Nishikori, C.
Ohta, E. Oberlin, R. Irie, T. Katsuki, Tetrahedron 1999, 55,
13937 – 13946; b) H. Nishikori, T. Katsuki, Appl. Catal. A 2000,
194 – 195, 475 – 477; c) M. Murakami, T. Uchida, T. Katsuki,
Tetrahedron Lett. 2001, 42, 7071 – 7074; d) C. Ohta, T. Katsuki,
Tetrahedron Lett. 2001, 42, 3885 – 3888; e) M. Murakami, T.
Katsuki, Tetrahedron Lett. 2002, 43, 3947 – 3949; f) M. Mura-
kami, T. Uchida, B. Saito, T. Katsuki, Chirality 2003, 15, 116 –
123; g) Y. Tamura, T. Uchida, T. Katsuki, Tetrahedron Lett. 2003,
44, 3301 – 3303; h) T. Uchida, Y. Tamura, M. Ohba, T. Katsuki,
Tetrahedron Lett. 2003, 44, 7965 – 7968; i) H. Fujita, T. Uchida,
R. Irie, T. Katsuki, Chem. Lett. 2007, 36, 1092 – 1093.
[6] For selected examples, see: a) T. Bach, C. Korber, Tetrahedron
Lett. 1998, 39, 5015 – 5016; b) T. Bach, C. Kçrber, Eur. J. Org.
Chem. 1999, 1033 – 1039; c) W. Ou, Z.-C. Chen, Synth. Commun.
1999, 29, 4443 – 4449; d) A. L. Marzinzik, K. B. Sharpless, J. Org.
Chem. 2001, 66, 594 – 596; e) G. Y. Cho, C. Bolm, Org. Lett. 2005,
7, 4983 – 4985; f) G. Y. Cho, C. Bolm, Tetrahedron Lett. 2005, 46,
8007 – 8008; g) O. Garcꢂa MancheÇo, C. Bolm, Org. Lett. 2006, 8,
2349 – 2352; h) O. Garcꢂa MancheÇo, C. Bolm, Chem. Eur. J.
2007, 13, 6674 – 6681; i) O. Garcꢂa MancheÇo, O. Bistri, C. Bolm,
Org. Lett. 2007, 9, 3809 – 3811; j) O. Garcꢂa MancheÇo, J.
Dallimore, A. Plant, C. Bolm, Org. Lett. 2009, 11, 2429 – 2432;
k) O. Garcꢂa MancheÇo, J. Dallimore, A. Plant, C. Bolm, Adv.
Synth. Catal. 2010, 352, 309 – 316; l) A. Pandey, C. Bolm,
Synthesis 2010, 2922 – 2925.
[18] For selected examples covering oxidations of N-acyl sulfimides,
see: a) N. Gaggero, L. D’Accolti, S. Colonna, R. Curci,
Tetrahedron Lett. 1997, 38, 5559 – 5562; b) Y. Macꢁ, C. Urban,
C. Pradet, J. Marrot, J.-C. Blazejewski, E. Magnier, Eur. J. Org.
Chem. 2009, 3150 – 3153.
[19] C. Abebrese, Y. Huang, A. Pan, Z. Yuan, R. Zhang, J. Inorg.
Biochem. 2011, 105, 1555 – 1561.
[7] H. Kise, G. F. Whitfield, D. Swern, J. Org. Chem. 1972, 37, 1121 –
1125.
[8] G. F. Koser, P. B. Kokil, M. Shah, Tetrahedron Lett. 1987, 28,
5431 – 5434.
[20] For the use of RuO2 and sodium periodate in sulfide oxidations,
see: a) H. S. Veale, J. Levin, D. Swern, Tetrahedron Lett. 1978,
19, 503 – 506; b) D. M. Ketcha, D. Swern, Synth. Commun. 1984,
14, 915 – 919.
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Synthetic Methods
V. Bizet, L. Buglioni,
C. Bolm*
&&&& — &&&&
Light-Induced Ruthenium-Catalyzed
Nitrene Transfer Reactions: A
Photochemical Approach towards N-Acyl
Sulfimides and Sulfoximines
Double duty: A one-pot sulfur imidation/
oxidation sequence using a single ruthe-
nium complex for both steps was devel-
oped (see scheme). Photochemical
decarboxylations of 1,4,2-dioxazol-5-ones
provide N-acyl nitrenes, which imidate
sulfides at ambient temperature. The
subsequent oxidation then occurs under
mild phase-transfer catalysis conditions.
In this manner, N-acyl sulfimides and
sulfoximines can be obtained in high
yields starting from sulfides.
Angew. Chem. Int. Ed. 2014, 53, 1 – 5
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
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