Enantioselective intramolecular copper-catalyzed aziridination of sulfamates

Article abstract of DOI:10.1055/s-2007-965987

Intramolecular copper-catalyzed aziridination of sulfamates occurs in very good yields of up to 86% and in up to 84% ee in the presence of (4S,4′S)-2,2′-(propane-2,2-diyl)bis(4-tert-butyl-4,5-dihydro-1, 3-oxazole). The resulting aziridines undergo smooth

Full text of DOI:10.1055/s-2007-965987

SPECIAL TOPIC
1251
Enantioselective Intramolecular Copper-Catalyzed Aziridination of
Sulfamates
Enantioselective
C
u
opper-Cataly
d
zed
A
ziridin
r
ation of
eSulfamatesy Estéoule, Fernando Durán, Pascal Retailleau, Robert H. Dodd,* Philippe Dauban*
Institut de Chimie des Substances Naturelles, CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France
Fax +33(1)69077247; E-mail: robert.dodd@icsn.cnrs-gif.fr; E-mail: philippe.dauban@icsn.cnrs-gif.fr
Received 6 February 2007
combination of copper salts and iodosylbenzene has al-
lowed the development of an intramolecular procedure
starting from sulfamates that allows the isolation of aziri-
dines from simple aliphatic alkenes in good yields
Abstract: Intramolecular copper-catalyzed aziridination of sulfa-
mates occurs in very good yields of up to 86% and in up to 84% ee
in the presence of (4S,4¢S)-2,2¢-(propane-2,2-diyl)bis(4-tert-butyl-
4,5-dihydro-1,3-oxazole). The resulting aziridines undergo smooth
ring opening with different types of nucleophiles in an SN2-type (Scheme 1).14 It thus appealed to us to test the ability of
process.
chiral copper complexes to induce enantioselective in-
tramolecular aziridination of olefins well-known for be-
ing poorly reactive under these conditions. In this
communication, we describe our results obtained in this
context, and which can be considered as the first catalytic
asymmetric nitrene transfers to aliphatic alkenes.
Key words: aziridine, nitrene, copper, asymmetric catalysis, ring
opening
Aziridines hold a predominant place in total synthesis of
natural and/or biologically active nitrogen-containing
products because their ring opening by nucleophiles al-
lows the formation of a large variety of substituted amino
derivatives.1,2 This synthetic interest has led to the devel-
opment of several methodologies for the preparation of
aziridines,1,3 among which catalytic nitrene addition to
alkenes has been extensively studied in the past few
years.4
O
O
O O
PhI=O
10 mol% CuPF6
S
S
O
NH2
O
N
R2
R2
MeCN, 3 Å MS
R1
R1
n
n
Scheme 1 Intramolecular copper-catalyzed aziridination of sulfa-
mates
A majority of these catalytic aziridinations involves
iminoiodanes5 as nitrene precursors in the presence of
transition metal complexes. From a synthetic point of
view, copper6 and rhodium7 complexes are the catalysts of
choice. The capacity of copper to catalyze competitive C–
H amination under these conditions is, however, lower
than that of rhodium.4,8 Copper-catalyzed aziridination
has also been successfully applied to the total synthesis of
natural products or biologically active compounds.9,10
Unsaturated sulfamates 2a–j could easily be prepared
from the corresponding alcohols 1 by application of a re-
cently published procedure (Scheme 2).15 This involves
the reaction of alcohols 1 in N,N-dimethylacetamide
(DMA) with the sulfamoyl chloride generated in situ from
chlorosulfonyl isocyanate and formic acid. Primary and
secondary alcohols 1 can be transformed into sulfamates
2a–j in very good yields (73–95%) (Scheme 2). Sulfa-
mates 2a–j are stable compounds that can be stored for
several months at –20 °C without decomposition.
Another key feature of copper is the possibility of using
chiral ligands to form aziridines in nearly enantiomerical-
ly pure form.11 In this context, chiral C2-symmetrical di-
imines and chiral bis(oxazolines) have been found to be
highly efficient, since enantiomeric excesses of up to 99%
can be obtained. These asymmetric nitrene transfers are,
however, limited to styrene-type derivatives such as cin-
namates, chalcones, or chromenes.
O
O
S
OH R3
H2N
O
R3
ClSO2N=C=O
HCOOH
R5
R5
R1
R1
n
n
R2
R4
R2
R4
DMA, 0 °C to r.t.
1
2a: R1, R2, R3, R4 = H, R5 = Ph, n = 1, 82%
2b: R1, R2, R3, R4, R5 = H, n = 1, 95%
We and others have recently demonstrated that imi-
noiodanes could be generated in situ,12 a procedure that
highly facilitates their troublesome handling and enhanc-
es the variety of nitrogen compounds which can be used
as nitrene sources. Among the latter, sulfamates have
proven to be efficient and versatile reagents which broad-
en the scope of nitrene transfer.7b,13,14 In particular, the
2c: R1, R2 = H, R3 = Me, R4, R5 = H, n = 1, 95%
2d: R1, R2, R3, R4 = H, R5 = Me, n = 1, 74%
2e: R1, R2, R3, R4 = H, R5 = Et, n = 1, 95%
2f: R1, R2, R3 = H, R4 = Et, R5 = H, n = 1, 93%
2g: R1, R2, R3, R4 = H, R5 = CO2Me, n = 1, 73%
2h: R1 = Me, R2, R3, R4, R5 = H, n = 1, 92%
2i: R1 = H, R2 = Me, R3, R4, R5 = H, n = 1, 84%
2j: R1, R2, R3, R4, R5 = H, n = 2, 80%
Scheme 2 Preparation of unsaturated sulfamates 2a–j
SYNTHESIS 2007, No. 8, pp 1251–1260
x
x
.
x
x
.2
0
0
7
Advanced online publication: 12.03.2007
DOI: 10.1055/s-2007-965987; Art ID: C00207SS
© Georg Thieme Verlag Stuttgart · New York

1252
A. Estéoule et al.
SPECIAL TOPIC
We then turned our attention to the asymmetric intramo-
lecular catalytic aziridination of sulfamates 2. The optimal
reaction conditions were first established with sulfamate
2a (Table 1). Initial experiments indicated that diimino-
cyclohexane 3a11a and bis(oxazolines) 3b and 3c11b
(Figure 1) gave the best results (data not shown). It should
be mentioned that the asymmetric aziridination of sulfa-
mate 2a took place stereospecifically, since we obtained
only the trans-aziridine 4a (Table 1).
O
O
N
N
N
Ph
Ph
3b
Cl
N
N
Cl
Cl
Cl
O
O
3a
N
t-Bu
t-Bu
3c
Using these ligands, we then screened different reaction
parameters (Table 1). At room temperature, aziridine 4a
was isolated in approximately the same good yields in the
75–80% range both in the absence (Table 1, entry 1) and
presence (entries 2, 4, 6) of ligands 3a–c. However, at a
lower temperature of –20 °C, the yields markedly dropped
to 48% and 40% respectively, in the cases of diimine 3a and
bis(oxazoline) 3b (Table 1, entries 3 and 5), while a yield
of 75% was maintained with the bis(tert-butyloxazoline)
3c (entry 7). Moreover, as far as the enantioselectivity is
concerned, the highest enantiomeric excess, i.e. 76%, was
obtained at –20 °C, again in the presence of ligand 3c,
which was therefore used for further optimization.
Figure 1
cy in terms of reactivity of the nitrene transfer. However,
lower enantiomeric excesses of around 65% were ob-
tained. Interestingly, when the catalytic amount of the
chiral copper complex was reduced to 5 mol%, we could
isolate aziridine 4a at –20 °C in a higher yield of 86% and
a better enantioselectivity of 84% (Table 1, entry 10). Fi-
nally, acetonitrile was found to be the solvent of choice,
since reactions conducted in benzene and dichloro-
methane afforded aziridine 4a in lower yields and in very
modest enantioselectivities of 32% and 25% ee, respec-
tively (Table 1, entries 11 and 12).
To further improve the enantioselectivity, the reaction
was run at lower temperatures, at –30 °C and –40 °C
(Table 1, entries 8 and 9). This did not affect the efficien-
These optimal conditions, that is, 5 mol% [Cu(NC-
Me)4]PF6 in the presence of 5.5 mol% ligand 3c at –20 °C
in acetonitrile, were then applied to sulfamates 2b–j
(Table 2).16 The asymmetric copper-catalyzed aziridina-
tion of sulfamate 2b gave encouraging results, since, in
contrast to substrate 2a, the C=C bond of 2b is not conju-
gated to an aromatic system. The corresponding aziridine
4b was isolated in 81% yield and 52% ee (Table 2, entry
2).
Table 1 Determination of the Optimal Aziridination Conditions
with Sulfamate 2aa
O
O
O
O
S
S
Ph
O
NH2
O
N
Ph
H
2a
4a
Application of these conditions to disubstituted alkenes
then indicated that the substitution pattern of the olefin
has an influence on the reactivity. For instance, the reac-
tion with the gem-disubstituted alkene 2c was disappoint-
ing (Table 2, entry 3). The aziridine 4c was obtained in a
low yield of 24% and in modest enantioselectivity of 36%.
By contrast, disubstituted trans- and cis-olefins 2d–g dis-
played higher reactivity under these conditions, since the
corresponding aziridines 4d–g were isolated in 80%,
83%, 86%, and 79% yields, respectively (Table 2, entries
4–7). Moreover, good enantiomeric excesses of 80% for
the trans-products 4d and 4e, and 72% for the cis-isomer
4f were observed. Surprisingly, while the copper-cata-
lyzed aziridination of the trans-alkenes 2a, 2d, 2e, and 2g
was stereospecific, this was not the case for the cis-sulfa-
mate 2f, since traces of the trans-aziridine 4e could be iso-
lated from the reaction mixture. While most copper-
catalyzed nitrene transfers are believed to occur by a con-
certed pathway involving singlet nitrenes,4b,6a,17 the afore-
mentioned result indicates the intermediacy of triplet
nitrene of radical character. It should also be noted that,
although slightly lower than that of compounds 4a, 4d,
and 4e, the enantiomeric excess of 62% observed with
sulfamate 4g is the first so far described for the aziridina-
tion of an a,b-unsaturated ester (with the exception of cin-
Entry
1
Ligand
none
3a
Temp (°C) Solvent
Yieldb (%) eec (%)
25
25
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
MeCN
benzene
CH2Cl2
78
75
48
80
40
80
75
72
72
86
56
60
–
2
56
45
14
20
63
76
65
66
84
32
25
3
3a
–20
25
4
3b
5
3b
–20
25
6
3c
7
3c
–20
–30
–40
–20
25
8
3c
9
3c
10d
11
12
3c
3c
3c
25
a Reagents and conditions: [Cu(NCMe)4]PF6 (10 mol%), ligand 3 (11
mol%), PhIO, 3-Å MS, MeCN.
b Isolated yield after column chromatography.
c The ee values were determined by HPLC (OD column).
d With [Cu(NCMe)4]PF6 (5 mol%).
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

SPECIAL TOPIC
Enantioselective Copper-Catalyzed Aziridination of Sulfamates
1253
namates).18 This result paves the way for an Table 2 Enantioselective Intramolecular Aziridination of Sulfa-
mates 2a
enantioselective synthesis of amino acids.1a,2b
Asymmetric intramolecular nitrene transfer was also at-
tempted with substituted sulfamates. Starting from the
secondary derivative 2h, the corresponding aziridine 4h
was isolated in a very good yield of 82% (Table 2, entry
8). However, the use of the chiral bis(oxazoline) 3c had an
influence on the diastereoselectivity. A 30:70 ratio in fa-
vor of the trans-4h isomer was obtained in this case, while
the cis-aziridine 4h was the major compound formed in a
diastereomeric ratio of 86:14 under racemic conditions.19
The same trend was observed with sulfamate 2i, the azir-
idine 4i being isolated in 85% yield and with a reversed
cis/trans diastereomeric ratio of 45:55 (Table 2, entry 9)
instead of 2:1 in the absence of ligand 3c. As far as the
enantioselectivity is concerned, the enantiomeric excess
was always higher for the minor cis-aziridine.
Entry Product
Yieldb (%)
86
eec (%)
84
O
O
S
S
S
S
S
S
S
Ph
O
N
1
2
3
4
5
6d
7
8
4a
4b
4c
4d
4e
4f
H
H
O
O
O
N
81
52
O
O
O
N
24
36
Me
O
O
Finally, the homologous sulfamate 2j was subjected to
asymmetric intramolecular aziridination and gave aziri-
dine 4j in good yield (72%) but moderate enantioselectiv-
ity (47% ee) (Table 2, entry 10).
Me
O
N
80
80
H
H
H
H
O
O
The results in Table 2 show that the reactivities of simple
aliphatic alkenes 2b–j are similar to that of alkene 2a con-
jugated to a benzene ring. This intramolecular process
therefore broadens the scope of the enantioselective cop-
per-catalyzed aziridination, previously confined to sty-
rene-type derivatives, to other olefins. The asymmetric
synthesis of nitrogen-containing compounds can therefore
be envisaged starting from the resulting aziridines 4, since
it has been demonstrated previously by Du Bois13b,f and
our group14 that they undergo regioselective ring opening
with nitrogen, oxygen, and sulfur nucleophiles. This pos-
sibility was confirmed with the bicyclic aziridine 4d,
whose reaction with benzylamine or p-bromobenzyl alco-
hol (PBBOH) afforded the seven-membered cyclic sulfa-
midates 5d and 6 in 57% and 55% yield, respectively
(Scheme 3).
Et
O
N
83
80
O
O
O
N
86
72
Et
O
O
CO2Me
O
N
79
62
4g
O
O
S
82 (30:70)e
78, 24f
O
N
4h
H
O
O
O
O
1.2 equiv BnNH2
0.2 equiv Et3N
S
O
NH
S
9
85 (45:55)e
68, 28f
O
N
Me
NHBn
O
O
THF, r.t., 5 h
5d
57%
S
Me
4i
4j
H
O
N
5
4
O
O
O
O
H
1.2 equiv PBBOH
0.1 equiv BF3⋅OEt2
S
S
10
72
47
4d
O
N
O
NH
Me
OPBB
H
CH2Cl2, r.t., 7 h
6
55%
a Reagents and conditions: 2 (1 equiv), [Cu(NCMe)4]PF6 (5 mol%),
ligand 3c (5.5 mol%), PhIO (1.5 equiv), 3-Å MS, MeCN, –20 °C.
b Isolated yield after column chromatography.
Scheme 3 Regioselective nucleophilic ring opening of aziridine 4d
c The ee values were determined by HPLC (OD or AD column) after
ring opening of aziridines 4 with BnNH2.
As mentioned before,16 the enantiomeric excesses mea-
sured for these ring-opened products 5d and 6 were iden-
tical to that of the aziridine 4d, i.e. 80%. Compound 6
could be recrystallized and obtained in an optically pure
form. X-ray crystallography (Figure 2) allowed the deter-
mination of the absolute configuration, namely 4S,5R, of
the asymmetric centers formed during enantioselective
d Traces of the trans-aziridine 4e were isolated.
e The cis/trans ratio.
f The ee values of the cis- and trans-isomers, respectively.
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

1254
A. Estéoule et al.
SPECIAL TOPIC
over 3-Å MS. All reagents were purchased from Aldrich Chemical
Co. and were used without further purification. Elemental analyses
were performed at the ICSN, CNRS, Gif-sur-Yvette, France.
Sulfamates 2a–j; General Procedure
HCO2H (1.70 mL, 45 mmol, 1.5 equiv) was added dropwise to neat
ClSO2NCO (3.90 mL, 45 mmol, 1.5 equiv) at 0 °C with rapid stir-
ring. Gas evolved during the addition. The resulting viscous suspen-
sion was stirred for 18 h at r.t. The mixture was cooled to 0 °C,
DMA (8 mL) was added, and the soln was stirred for 5 min. A soln
of the appropriate alkenol 1 (1 equiv) in DMA (16 mL) was added
dropwise, the resulting soln was allowed to warm to r.t., and stirring
was continued until the reaction was complete (3–4 h) as deter-
mined by TLC. The reaction was quenched by the successive addi-
tion of EtOAc (40 mL) and sat. aq NaCl (20 mL). The mixture was
poured into EtOAc (80 mL) and H2O (30 mL). The organic phase
was collected and the aqueous layer was extracted with EtOAc
(2 × 30 mL). The organic extracts were combined, washed with sat.
aq NaCl (2 × 30 mL), dried (MgSO4), and concentrated under re-
duced pressure. Purification of the residue by flash chromatography
(silica gel, heptane–EtOAc) afforded the desired sulfamic ester.
Figure 2 ORTEP view of the crystal structure of 6 at the 30% pro-
bability level
aziridination. It was also deduced that the intramolecular
nitrene addition occurs preferentially via the si face while
the nucleophilic ring opening takes place by an SN2-type
process.
The ORTEP view of 6 (Figure 2) also clearly confirmed
the regioselectivity of the ring opening, i.e. at the C-5 po-
sition of aziridine 4d. This result was tentatively rational-
ized by modeling calculations of aziridines of type 4. It
was found that the C5–N bond (1.47 Å) is slightly longer
(E)-4-Phenylbut-3-enyl Sulfamate (2a)
Sulfamate 2a was prepared from 4-phenylbut-3-en-1-ol, and was
purified by chromatography (silica gel, heptane–EtOAc, 3:7).
Yield: 82%; white solid; mp 92–93 °C; Rf = 0.24 (heptane–EtOAc,
than the C4–N bond (1.45 Å), and therefore more likely to 6:4).
undergo nucleophilic displacement. In a recent paper,13f
Du Bois and co-workers reported that the same trend was
observed when the X-ray structures of the starting bicyclic
aziridine and the subsequent ring-opened product were
compared. Additional convincing data were also provided
by the same authors that are all fully consistent with our
experimental findings.
IR (neat): 3402, 3312, 1534, 1345, 1170, 967, 929, 747 cm–1.
1H NMR (300 MHz, CDCl3): d = 2.59 (dq, J = 6.5, 1.3 Hz, 2 H),
4.24 (t, J = 6.6 Hz, 2 H), 4.72 (br s, 2 H), 6.09 (dt, J = 15.9, 7.0 Hz,
1 H), 6.44 (dt, J = 15.9 Hz, 1 H), 7.13–7.30 (m, 5 H).
13C NMR (75 MHz, CDCl3): d = 32.4, 70.5, 124.0, 126.2, 127.6,
128.6, 133.4, 136.9.
ESI-MS: m/z (%) = 250.0 (100) [M + Na+], 477.1 (29) [2 × M +
In conclusion, chiral copper complexes efficiently cata- Na+].
HRMS [ESI(+)]: m/z [M + Na+] calcd for C10H13NO3S: 250.0514;
found: 250.0509.
lyze the intramolecular aziridination of sulfamates in
yields of up to 86% and enantiomeric excesses of up to
84%. In particular, this nitrene transfer occurs with equal
success for simple aliphatic olefins and electron-poor alk-
enes, substrates for which no enantioselective aziridina-
tion has been reported before. The resulting aziridine
undergoes a clean SN2-type nucleophilic ring opening
But-3-enyl Sulfamate (2b)
Sulfamate 2b was prepared from but-3-en-1-ol, and was purified by
chromatography (silica gel, heptane–EtOAc, 3:7).
Yield: 95%; yellow oil; Rf = 0.44 (heptane–EtOAc, 6:4).
with excellent regioselectivity. The latter offers the oppor- IR (neat): 3384, 3288, 3084, 2985, 2907, 1643, 1556, 1360, 1178,
920, 776 cm–1.
tunity of introducing a second nucleophile at the C–O po-
1H NMR (250 MHz, CDCl3): d = 2.52 (ddt, J = 13.2, 6.4, 1.5 Hz, 2
H), 4.27 (t, J = 6.6 Hz, 2 H), 4.81 (s, 2 H), 5.16 (m, 1 H), 5.19 (ddd,
J = 17.1, 3.5, 1.5 Hz, 1 H), 5.81 (ddt, J = 17.1, 10.3, 6.6 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d = 33.1, 70.4, 118.4, 132.7.
ESI-MS: m/z (%) = 152 (28) [M + H+], 174 (100) [M + Na+].
sition, a reaction that has been demonstrated to occur after
carbamoylation of the nitrogen atom.13a,f,14,20 Stereoselec-
tive access to enantiopure substituted amines is therefore
conceivable by application of this strategy, an area of in-
vestigation that is currently in progress in our laboratory.
Anal. Calcd for C4H9NO3S: C, 31.78; H, 6.00; N, 9.26; S, 21.21.
Found: C, 31.82; H, 6.06; N, 9.12; S, 20.83.
Melting points were measured in capillary tubes on a Büchi B-540
apparatus and are uncorrected. IR spectra were recorded with a Per-
kin Elmer Spectrum BX FT-IR spectrometer. 1H (300 or 250 MHz)
and 13C (75 MHz) NMR spectra were measured on a Bruker Aspect
3000 (300 MHz) instrument. EI and CI mass spectra were recorded
on an AEI MS-50 and AEI MS-9 spectrometer, respectively. High-
resolution mass spectra were obtained on a Kratos MS-80 spectrom-
eter. Optical rotations were determined with a JASCO P-1010 pola-
rimeter. Chiral HPLC was performed on a Waters 2695
spectrometer coupled with a Waters 996 Photodiode Array Detector
(PDA) with a ChiralCel™ OD column (10 mm, 250 × 4.6 mm) or a
ChiralPack™ AD column (10 mm, 250 × 4.6 mm). All solvents were
distilled except DMA (N,N-dimethylacetamide), which was stored
3-Methylbut-3-enyl Sulfamate (2c)
Sulfamate 2c was prepared from 3-methylbut-3-en-1-ol, and was
purified by chromatography (silica gel, heptane–EtOAc, 3:7).
Yield: 95%; yellow oil; Rf = 0.47 (heptane–EtOAc 6:4).
IR (neat): 3376, 3287, 3081, 2973, 1614, 1557, 1366, 1180, 972,
925, 784 cm–1.
1H NMR (250 MHz, CDCl3): d = 1.78 (s, 3 H), 2.47 (t, J = 6.8 Hz,
2 H), 4.32 (t, J = 6.8 Hz, 2 H), 4.80 (s, 1 H), 4.87 (s, 1 H), 4.95 (s, 2
H).
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

SPECIAL TOPIC
Enantioselective Copper-Catalyzed Aziridination of Sulfamates
1255
13C NMR (75 MHz, CDCl3): d = 22.5, 36.3, 69.3, 113.0, 140.6.
ESI-MS: m/z (%) = 188 (100) [M + Na+].
1H NMR (300 MHz, CDCl3): d = 2.63 (qd, J = 6.5, 1.6 Hz, 2 H),
3.71 (s, 3 H), 4.29 (t, J = 6.3 Hz, 2 H), 5.03 (s, 2 H), 5.93 (dd,
J = 15.7, 1.5 Hz, 1 H), 6.89 (dt, J = 15.6, 6.8 Hz, 1 H).
Anal. Calcd for C5H11NO3S·l/7 DMA: C, 37.44; H, 7.48; N, 8.95; S,
17.97. Found: C, 37.71; H, 7.10; N, 9.00; S, 17.64.
13C NMR (75 MHz, CDCl3): d = 31.4, 51.7, 68.7, 123.9, 143.0,
166.6.
(E)-Pent-3-enyl Sulfamate (2d)
ESI-MS: m/z (%) = 232.0 (100) [M + Na+].
Sulfamate 2d was prepared from (E)-pent-3-en-1-ol, and was puri-
fied by chromatography (silica gel, heptane–EtOAc, 6:4).
HRMS [ESI(+)]: m/z [M + Na+] calcd for C6H11NO5S: 232.0256;
found: 232.0245.
Yield: 74%; salmon-colored oil; Rf = 0.47 (heptane–EtOAc, 6:4).
1-Methylbut-3-enyl Sulfamate (2h)
Sulfamate 2h was prepared from pent-4-en-2-ol, and was purified
by chromatography (silica gel, heptane–EtOAc, 3:7).
IR (neat): 3279, 2919, 2856, 1613, 1556, 1357, 1174, 966, 917 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.65 (dq, J = 6.4, 1.2 Hz, 3 H),
2.40 (qq, J = 6.7, 1.1 Hz, 2 H), 4.16 (t, J = 6.7 Hz, 2 H), 5.01 (br s,
2 H), 5.37 (m, 1 H), 5.56 (m, 1 H).
Yield: 92%; yellow oil; Rf = 0.44 (heptane–EtOAc, 6:4).
IR (neat): 3381, 3286, 3082, 2983, 2939, 1558, 1358, 1182, 920,
793, 765 cm–1.
1H NMR (250 MHz, CDCl3): d = 1.43 (d, J = 5.9 Hz, 3 H), 2.46 (m,
2 H), 4.75 (sext, J = 6.3 Hz, 1 H), 4.86 (s, 2 H), 5.13 (m, 1 H), 5.18
(m, 1 H), 5.81 (m, 1 H).
13C NMR (75 MHz, CDCl3): d = 20.1, 40.6, 80.3, 118.9, 132.6.
ESI-MS: m/z (%) = 187.8 (100) [M + Na+].
13C NMR (75 MHz, CDCl3): d = 18.0, 32.0, 70.9, 124.9, 129.1.
ESI-MS: m/z (%) = 188.0 (30) [M + Na+], 220.0 (100) [M + MeOH
+ Na+].
HRMS [ESI(+)]: m/z [M + Na+] calcd for C5H11NO3S: 188.0357;
found: 188.0366.
(E)-Hex-3-enyl Sulfamate (2e)
Sulfamate 2e was prepared from (E)-hex-3-en-1-ol, and was puri-
fied by chromatography (silica gel, heptane–EtOAc, 3:7).
Anal. Calcd for C5H11NO3S: C, 36.35; H, 6.71; N, 8.48; S, 19.41.
Found: C, 36.47; H, 6.85; N, 8.42; S, 19.12.
Yield: 95%; yellow oil; Rf = 0.5 (heptane–EtOAc, 6:4).
2-Methylbut-3-enyl Sulfamate (2i)
Sulfamate 2i was prepared from 2-methylbut-3-en-1-ol, and was
purified by chromatography (silica gel, heptane–EtOAc, 6:4).
IR (neat): 3383, 3288, 2965, 2935, 1556, 1365, 1182, 970, 932, 814,
775 cm–1.
1H NMR (250 MHz, CDCl3): d = 0.98 (t, J = 7.3 Hz, 3 H), 2.02
(quin, J = 7.1 Hz, 2 H), 2.45 (q, J = 7.1 Hz, 2 H), 4.21 (t, J = 7.1 Hz,
2 H), 4.78 (s, 2 H), 5.38 (dt, J = 15.6, 6.7 Hz, 1 H), 5.63 (dt,
J = 15.6, 6.7 Hz, 1 H).
13C NMR (75MHz, CDCl3): d = 13.7, 25.7, 32.1, 71.1, 122.7, 136.3.
ESI-MS: m/z (%) = 181 (10) [M + H+], 202 (100) [M + Na+].
Yield: 84%; colorless oil; Rf = 0.67 (heptane–EtOAc 4:6).
IR (neat): 3377, 3280, 1556, 1355, 1175, 969, 916 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.1 (d, J = 6.8 Hz, 3 H), 2.62 (m,
1 H), 4.02 (dd, J = 9.4, 6.7 Hz, 1 H), 4.11 (dd, J = 9.4, 6.7 Hz, 1 H),
4.87 (br s, 2 H), 5.10 (dt, J = 10.4, 1.1 Hz, 1 H), 5.14 (dt, J = 17.3,
1.1 Hz, 1 H), 5.8 (ddd, J = 17.3, 10.4, 7 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d = 16.0, 39.9, 74.8, 116.1, 138.6.
ESI-MS: m/z (%) = 188.0 (20) [M + Na+], 421.0 (100).
Anal. Calcd for C6H13NO3S: C, 40.21; H, 7.31; N, 7.81; S, 17.89.
Found: C, 40.33; H, 7.56; N, 7.61; S, 17.84.
(Z)-Hex-3-enyl Sulfamate (2f)
Sulfamate 2f was prepared from (Z)-hex-3-en-1-ol, and was puri-
fied by chromatography (silica gel, heptane–EtOAc, 3:7).
HRMS [ESI(+)]: m/z [M + Na+] calcd for C5H11NO3S: 188.0357;
found: 188.0349.
Yield: 93%; yellow oil; Rf = 0.53 (heptane–EtOAc, 6:4).
Pent-4-enyl Sulfamate (2j)
Sulfamate 2j was prepared from pent-4-en-1-ol, and was purified by
chromatography (silica gel, heptane–EtOAc, 3:7).
IR (neat): 3383, 3288, 3014, 2966, 2935, 2876, 1555, 1465, 1364,
1181, 972, 929, 778 cm–1.
Yield: 80%; yellow oil; Rf = 0.5 (heptane–EtOAc 6:4).
1H NMR (250 MHz, CDCl3): d = 0.99 (t, J = 7.4 Hz, 3 H), 2.07
(quin, J = 7.4 Hz, 2 H), 2.51 (q, J = 6.6 Hz, 2 H), 4.20 (t, J = 6.6 Hz,
2 H), 4.86 (s, 2 H), 5.33 (m, 1 H), 5.57 (m, 1 H).
IR (neat): 3383, 3288, 3014, 2966, 2935, 2876, 1555, 1465, 1364,
1181, 972, 929, 778 cm–1.
13C NMR (75 MHz, CDCl3): d = 14.1, 20.7, 26.9, 70.8, 122.4,
1H NMR (250 MHz, CDCl3): d = 1.87 (quin, J = 6.6 Hz, 2 H), 2.20
(q, J = 7.4 Hz, 2 H), 4.24 (t, J = 6.3 Hz, 2 H), 4.83 (s, 2 H), 5.01 (m,
1 H), 5.08 (ddd, J = 16.9, 3.0, 1.5 Hz, 1 H), 5.80 (ddt, J = 16.9, 10.3,
6.6 Hz, 1 H).
13C NMR (CDCl3, 75 MHz): d = 13.7, 25.7, 32.1, 71.1, 122.7,
136.3.
135.6.
ESI-MS: m/z (%) = 233.9 (100) [M + MeOH + Na+], 201.9 (22) [M
+ Na+].
Anal. Calcd for C6H13NO3S: C, 40.21; H, 7.31; N, 7.81; S, 17.89.
Found: C, 40.37; H, 7.59; N, 7.65; S, 17.72.
ESI-MS: m/z (%) = 187.8 (100) [M + Na+].
Methyl (E)-5-(Sulfamoyloxy)pent-2-enoate (2g)
Sulfamate 2g was prepared from methyl (E)-5-hydroxypent-2-
enoate, and was purified by chromatography (silica gel, heptane–
EtOAc, 4:6).
Anal. Calcd for C5H11NO3S: C, 36.35; H, 6.71; N, 8.48. Found: C,
36.18; H, 6.95; N, 8.31.
3-Oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Dioxides 4a–i and
3-Oxa-2-thia-1-azabicyclo[5.1.0]octane 2,2-Dioxide 4j by Aziri-
dination of Alkenyl Sulfamates 2a–j; General Procedure
A soln of [Cu(NCMe)4]PF6 (55.4 mg, 0.15 mmol, 0.05 equiv) and
3c (48.1 mg, 0.16 mmol, 0.055 equiv) in MeCN (40 mL) containing
activated 3-Å MS (8 g) was stirred at –20 °C for 30 min under ar-
Yield: 73%; white solid; mp 53–54 °C; Rf = 0.56 (heptane–EtOAc
4:6).
IR (neat): 3336, 3255, 1682, 1655, 1553, 1361, 1171, 915 cm–1.
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

1256
A. Estéoule et al.
SPECIAL TOPIC
gon. A soln of the appropriate sulfamate 2 (2.97 mmol, 1 equiv) in
MeCN (40 mL) was introduced by cannula into the homogeneous
soln. PhIO (980 mg, 4.46 mmol, 1.5 equiv) was added and the mix-
ture was stirred at –20 °C for 48 h. The MS were removed by filtra-
tion over Celite and the filtrate was evaporated to dryness under
reduced pressure. The residue was purified by flash chromatogra-
phy (silica gel); this afforded the corresponding aziridine 4.
(E)-7-Methyl-3-oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Di-
oxide (4d)
Compound 4d was prepared from 2d, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 1:1).
Yield: 80%; peach-colored oil; Rf = 0.23 (heptane–EtOAc, 6:4).
IR (neat): 3474, 3148, 2923, 1449, 1350, 1177, 1042, 887, 768 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.34 (d, J = 5 Hz, 3 H), 2.20 (m,
1 H), 2.39 (m, 1 H), 2.92 (m, 2 H), 4.35 (ddd, J = 11.4, 6.0, 5.7 Hz,
1 H), 4.61 (ddd, J = 11.7, 5.8, 5.9 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d = 16.9, 18.8, 42.8, 48.8, 68.6.
(E)-7-Phenyl-3-oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Di-
oxide (4a)
Compound 4a was prepared from 2a, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 8:2).
ESI-MS: m/z (%) = 218.0 (100) [M + MeOH + Na+], 186.0 (50) [M
Yield: 86%; 84% ee; white solid; mp 94–95 °C; Rf = 0.28 (heptane–
EtOAc, 6:4); HPLC (OD column, hexane–EtOH, 9:1, flow rate: 1
mL/min, injected volume: 10 mL, detection: UV 225 nm); tR1 = 22.6
min, tR2 = 28.0 min.
+ Na+].
HRMS [ESI(+)]: m/z [M + Na+] calcd for C5H9NO3S: 186.0201;
found: 186.0206.
IR (neat): 2985, 1497, 1373, 1357, 1243, 1180, 1054, 955, 905, 693
cm–1.
1H NMR (300 MHz, CDCl3): d = 2.39 (m, 2 H), 3.18 (dq, J = 4.6,
3.2 Hz, 1 H), 3.80 (d, J = 4.4 Hz, 1 H), 4.46 (dt, J = 11.5, 6.4 Hz, 1
H), 4.70 (dt, J = 11.6, 6.8 Hz, 1 H), 7.19–7.32 (m, 5 H).
13C NMR (75 MHz, CDCl3): d = 18.8, 47.8, 50.4, 68.8, 126.3,
128.8, 134.2.
(E)-7-Ethyl-3-oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Di-
oxide (4e)
Compound 4e was prepared from 2e, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 7:3).
Yield: 83%; brown oil; Rf = 0.26 (heptane–EtOAc 6:4).
IR (neat): 2972, 2936, 2879, 1462, 1434, 1364, 1185, 1043, 1022,
965 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.06 (t, J = 7.4 Hz, 3 H), 1.52
(sext, J = 7.4 Hz, 1 H), 1.70 (m, 1 H), 2.22 (m, 1 H), 2.41 (ddd,
J = 15.1, 6.6, 5.9 Hz, 1 H), 2.84 (dt, J = 7.4, 4.4 Hz, 1 H), 3.03 (m,
1 H), 4.39 (dt, J = 11.7, 6.6 Hz, 1 H), 4.66 (dt, J = 11.7, 5.9 Hz, 1 H).
ESI-MS: m/z (%) = 280.0 (100) [M + MeOH + Na+], 248.0 (28) [M
+ Na+], 226.0 (12) [M + H+].
HRMS [ESI(+)]: m/z [M + Na+] calcd for C10H11NO3S: 248.0357;
found: 248.0337.
13C NMR (75 MHz, CDCl3): d = 10.3, 19.0, 24.6, 47.9, 48.5, 68.7.
3-Oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Dioxide (4b)
Compound 4b was prepared from 2b, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 1:1).
ESI-MS: m/z (%) = 199.8 (100) [M + Na+], 177.9 (64) [M + H+],
231.8 (78) [M + MeOH + Na+].
Anal. Calcd for C6H11NO3S: C, 40.66; H, 6.26; N, 7.90; S, 18.09;
Found: C, 40.89; H, 6.62; N, 7.50; S, 17.80.
Yield: 81%; brown oil; Rf = 0.36 (heptane–EtOAc, 1:2).
IR (neat): 3293, 2936, 1723, 1361, 1182, 1035, 982, 952, 932, 786
cm–1.
1H NMR (300 MHz, CDCl3): d = 2.26 (ddt, J = 15.1, 6.8, 6.4 Hz, 1
H), 2.51 (dq, J = 15.1, 6.4 Hz, 1 H), 2.65 (dd, J = 5.4, 1.5 Hz, 1 H),
2.73 (dd, J = 5.4, 1.5 Hz, 1 H), 3.22 (dd, J = 10.3, 5.4 Hz, 1 H), 4.43
(ddd, J = 11.7, 6.8, 6.4 Hz, 1 H), 4.69 (dt, J = 11.7, 6.4 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d = 18.4, 34.3, 41.6, 68.7.
MS (EI): m/z (%) = 150.0 (22) [M + H+], 110 (35), 55 (100).
(Z)-7-Ethyl-3-oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Di-
oxide (4f)
Compound 4f was prepared from 2f, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 1:1).
Yield: 86% (Z/E, 10:4); brown oil; Rf = 0.20 (heptane–EtOAc 6:4).
IR (neat): 2973, 2879, 1359, 1281, 1178, 1040, 962, 880, 789, 758
cm–1.
1H NMR (300 MHz, CDCl3): d = 1.12 (t, J = 7.3 Hz, 3 H), 1.75
(sext, J = 7.3 Hz, 1 H), 2.10 (m, 3 H), 2.70 (dt, J = 8.4, 5.4 Hz, 1 H),
3.37 (dt, J = 8.5, 5.4 Hz, 1 H), 4.45 (ddd, J = 11.7, 6.4, 1.5 Hz, 1 H),
4.83 (ddd, J = 12.5, 11.7, 4.4 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d = 10.9, 16.0, 17.0, 43.2, 47.0, 70.5.
MS (EI): m/z (%) = 178.0 (27) [M + H+], 83 (82), 68 (82), 54 (100).
Anal. Calcd for C4H7NO3S: C, 32.21; H, 4.73; N, 9.39; S, 21.50.
Found: C, 32.21; H, 4.79; N, 9.22; S, 21.31.
6-Methyl-3-oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Dioxide
(4c)
Compound 4c was prepared from 2c, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 6:4).
Anal. Calcd for C6H11NO3S: C, 40.66; H, 6.26; N, 7.90; S, 18.09;
Found: C, 40.88; H, 6.43; N, 7.62; S, 17.85.
Yield: 24%; brown oil; Rf = 0.17 (heptane–EtOAc, 6:4).
IR (neat): 2978, 2933, 1448, 1362, 1264, 1184, 1094, 1023, 961,
934 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.49 (s, 3 H), 2.26 (dt, J = 15.1,
5.8, 5.4 Hz, 1 H), 2.36 (m, 1 H), 2.45 (dt, J = 1.5 Hz, 1 H), 2.85 (dt,
J = 1.5 Hz, 1 H), 4.37 (ddd, J = 11.7, 8.3, 6.4 Hz, 1 H), 4.58 (ddd,
J = 11.7, 6.4, 5.4 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d = 24.4, 25.1, 40.3, 49.4, 67.8.
MS (EI): m/z (%) = 164.0 (45) [M + H+], 69 (95), 42 (100).
(E)-Methyl 3-Oxa-2-thia-1-azabicyclo[4.1.0]heptane-7-carbox-
ylate 2,2-Dioxide (4g)
Compound 4g was prepared from 2g, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 4:6).
Yield: 79%; colorless oil; Rf = 0.12 (heptane–EtOAc, 4:6).
IR (neat): 2960, 1741, 1445, 1368, 1181, 1053, 839, 788 cm–1.
1H NMR (300 MHz, CDCl3): d = 2.31 (m, 1 H), 2.46 (m, 1 H), 3.44
(m, 1 H), 3.46 (br s, 1 H), 3.78 (s, 3 H), 4.42 (dt, J = 12.0, 6.2 Hz, 1
H), 4.71 (m, 1 H).
Anal. Calcd for C5H9NO3S: C, 37.01; H, 5.71; S, 8.38; N, 19.41;
Found: C, 36.80; H, 5.56; S, 8.58; N, 19.65.
13C NMR (75 MHz, CDCl3): d = 16.9, 41.6, 45.0, 52.1, 67.8, 165.4.
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

SPECIAL TOPIC
Enantioselective Copper-Catalyzed Aziridination of Sulfamates
1257
ESI-MS: m/z (%) = 230.0 (100) [M + Na+].
HRMS [ESI(+)]: m/z [M + Na+] calcd for C6H9NO5S: 230.0099;
1,2,3-Oxathiazepane 2,2-Dioxides 5a–j by Ring Opening of
3-Oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Dioxides 4a–i and
3-Oxa-2-thia-1-azabicyclo[5.1.0]octane 2,2-Dioxide 4j; General
Procedure
found: 230.0101.
To determine the ee of the aziridine products 4a–j, they were de-
rivatized to the corresponding 1,2,3-oxathiazepanes 5a–j as fol-
lows: to a soln of the appropriate aziridine 4a–j (0.78 mmol, 1
equiv) in THF (1.3 mL) were added BnNH2 (102 mL, 0.93 mmol,
1.2 equiv) and Et3N (22 mL, 0.16 mmol, 0.2 equiv) at 20 °C under
argon. The mixture was stirred for 20 h and concentrated under re-
duced pressure. Purification of the residue by flash chromatography
(silica gel, CH2Cl2–MeOH–Et3N, 99:0.5:0.5) afforded the corre-
sponding 1,2,3-oxathiazepane 5a–j. Chiral-phase HPLC was used
for the determination of ee values.
4-Methyl-3-oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Dioxide
(4h)
Compound 4h was prepared from 2h, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 1:1).
Yield: 82% (dr 30:70); brown oil; Rf = 0.17 (minor) and 0.08 (major
diastereomer) (heptane–EtOAc, 6:4).
IR (neat): 2990, 2936, 1371, 1270, 1235, 1187, 971, 909, 865, 800
cm–1.
1H NMR (250 MHz, CDCl3): d (minor diastereomer, cis) = 1.43 (d,
J = 6.6 Hz, 3 H), 1.94 (ddd, J = 14.7, 3.7, 2.9 Hz, 1 H), 2.31 (ddd,
J = 14.7, 8.1, 4.4 Hz, 1 H), 2.43 (d, J = 5.1 Hz, 1 H), 2.58 (d, J = 5.1
Hz, 1 H), 3.20 (m, 1 H), 5.08 (m, 1 H); d (major diastereomer,
trans) = 1.47 (d, J = 6.3 Hz, 3 H), 2.35 (ddd, J = 15.3, 4.5, 1.6 Hz,
1 H), 2.41 (ddd, J = 15.3, 11.2, 2.4 Hz, 1 H), 2.63 (dd, J = 5.3, 1.9
Hz, 1 H), 2.88 (dd, J = 4.9, 1.9 Hz, 1 H), 3.15 (m, 1 H), 4.62 (dq,
J = 6.2, 4.7 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d (minor diastereomer) = 21.4, 26.3,
36, 41, 79.9; d (major diastereomer) = 21.4, 26.1, 29.7, 41, 76.2.
MS (CI): m/z (%) = 164.0 (100) [M + H+].
trans-N-Benzyl-4-phenyl-1,2,3-oxathiazepan-5-amine 2,2-Di-
oxide (5a)
From 4a; yield: 83%; 84% ee; white solid; mp 165–166 °C;
Rf = 0.54 (CH2Cl2–MeOH–Et3N, 99:0.5:0.5); HPLC (OD column,
hexane–i-PrOH–Et3N, 90:10:0.1, flow rate: 1 mL/min, injected vol-
ume: 10 mL, detection: UV 212 nm): tR1 = 25.9 min, tR2 = 31.3 min.
IR (neat): 3287, 3059, 2849, 1451, 1352, 1172, 1060, 938, 742, 700
cm–1.
1H NMR (300 MHz, DMSO-d6): d = 1.73 (br s, 1 H), 1.91 (m, 1 H),
2.31 (dt, J = 15, 3.7 Hz, 1 H), 2.97 (td, J = 9.5, 3.8 Hz, 1 H), 3.26
(d, J = 13.9 Hz, 1 H), 3.49 (d, J = 13.3 Hz, 1 H), 4.09 (d, J = 10.6
Hz, 1 H), 4.33 (m, 2 H), 6.86–6.94 (m, 2 H), 7.10–7.20 (m, 3 H),
7.27–7.40 (m, 5 H), 8.41 (br s, 1 H).
Anal. Calcd for C5H9NO3S·0.05C4H8O: C, 37.27; H, 5.65; N, 8.36;
S, 19.13; Found: C, 37.23; H, 5.46; N, 8.38; S, 18.91.
5-Methyl-3-oxa-2-thia-1-azabicyclo[4.1.0]heptane 2,2-Dioxide
(4i)
Compound 4i was prepared from 2i, and was purified by chroma-
13C NMR (75 MHz, DMSO-d6): d = 34.7, 49.8, 59.9, 61.2, 67.5,
126.4, 127.3, 127.6, 127.7, 127.9, 128.1, 140.3, 140.5.
ESI-MS: m/z (%) 355.1 (100) [M + Na+], 333.1 (92) [M + H+].
tography (silica gel, heptane–EtOAc, 8:2).
Yield: 85% (dr 45:55); brown oil; Rf = 0.38 (heptane–EtOAc, 4:6).
IR (neat): 2973, 1462, 1363, 1259, 1181, 975, 788 cm–1.
N-Benzyl-1,2,3-oxathiazepan-5-amine 2,2-Dioxide (5b)
From 4b; yield: 65%; 52% ee; white solid; mp 78–79 °C; Rf = 0.13
(CH2Cl2–MeOH–Et3N, 99:0.5:0.5); HPLC (OD column, hexane–
i-PrOH–Et3N, 90:10:0.1, flow rate: 1 mL/min, injected volume: 50
mL, detection: UV 262 nm): tR1 = 47.3 min, tR2 = 65.1 min.
1H NMR (300 MHz, CDCl3): d (minor diastereomer) = 1.13 (d,
J = 6.6 Hz, 3 H), 2.55 (m, 1 H), 2.78 (dd, J = 5.3, 1.5 Hz, 1 H), 2.85
(m, 1 H), 3.11 (qd, J = 5.2, 1.0 Hz, 1 H), 3.97 (dd, J = 11.7, 9.8 Hz,
1 H), 4.44 (qd, J = 6.0, 1.0 Hz, 1 H); d (major diastereomer) = 1.26
(d, J = 7.1 Hz, 3 H), 2.45 (m, 1 H), 2.57 (ddd, J = 11.6, 5.4, 1.0 Hz,
2 H), 2.9 (td, J = 5.1, 2.3 Hz, 1 H), 4.36 (dd, J = 15.3, 11.7 Hz, 1 H),
4.36 (dd, J = 30.1, 11.9 Hz, 1 H).
13C NMR (75 MHz, CDCl3): d (minor diastereomer) = 14.7, 23.4,
31.7, 46.4, 72.4; d (major diastereomer) = 16.8, 25.0, 35.2, 48.1,
74.2.
IR (neat): 3315, 3056, 2357, 1450, 1336, 1177, 1079, 947, 746, 695
cm–1.
1H NMR (300 MHz, CDCl3): d = 1.28 (br s, NH, 1 H), 1.75 (dt,
J = 15.8, 4.3 Hz, 1 H), 2.14 (ddt, J = 14.6, 11.3, 3.2 Hz, 1 H), 2.99
(q, J = 3.7 Hz, 1 H), 3.10 (ddd, J = 15.0, 4.3, 1.3 Hz, 1 H), 3.26 (d,
J = 15.5 Hz, 1 H), 3.65 (d, J = 13.0 Hz, 1 H), 3.72 (d, J = 13.0 Hz,
1 H), 4.06 (ddd, J = 13.0, 4.3, 2.5 Hz, 1 H), 4.46 (t, J = 12.3 Hz, 1
H), 5.50 (br s, 1 H), 7.15–7.34 (m, 5 H).
ESI-MS: m/z (%) = 218.0 (100) [M + MeOH + Na+], 186.0 (50) [M
+ Na+].
13C NMR (75 MHz, CDCl3): d = 34.9, 43.6, 51.1, 53.5, 65.2, 127.6,
128.0, 128.8, 139.2.
HRMS [ESI(+)]: m/z [M + Na+] calcd for C5H9NO3S: 186.0201;
found: 186.0206.
N-Benzyl-5-methyl-1,2,3-oxathiazepan-5-amine 2,2-Dioxide
(5c)
From 4c; yield: 46%; 36% ee; white solid; mp 98–99 °C; Rf = 0.28
(CH2Cl2–MeOH–Et3N, 99:0.5:0.5); HPLC (OD column, hexane–
i-PrOH–Et3N, 80:20:0.1, flow rate: 1 mL/min, injected volume: 50
mL, detection: UV 260 nm): tR1 = 16.2 min, tR2 = 27.8 min.
3-Oxa-2-thia-1-azabicyclo[5.1.0]octane 2,2-Dioxide (4j)
Compound 4j was prepared from 2j, and was purified by chroma-
tography (silica gel, heptane–EtOAc, 1:1).
Yield: 72%; brown oil; Rf = 0.14 (heptane–EtOAc, 6:4).
IR (neat): 2955, 2854, 1358, 1271, 1175, 1104, 1011, 951, 913, 841
cm–1.
IR (neat): 3296, 2961, 1413, 1342, 1181, 1068, 968, 904, 740, 694
cm–1.
1H NMR (250 MHz, CDCl3): d = 1.93 (m, 2 H), 2.50–2.40 (m, 2 H),
2.54 (d, J = 5.1 Hz, 1 H), 2.75 (d, J = 5.1 Hz, 1 H), 2.85 (m, 1 H),
4.23 (m, 2 H).
13C NMR (75 MHz, CDCl3): d = 26.3, 26.6, 32.9 (br), 39.8, 71.5.
MS (EI): m/z (%) = 164.0 (11) [M + H+], 71 (36), 42 (55), 41 (100).
1H NMR (300 MHz, CDCl3): d = 0.91 (br s, 1 H), 1.16 (s, 3 H), 1.74
(ddd, J = 16.1, 3.0, 2.3 Hz, 1 H), 1.92 (ddd, J = 16.1, 11.5, 2.8 Hz,
1 H), 2.87 (dd, J = 15.2, 3.4 Hz, 1 H), 3.17 (d, J = 14.8 Hz, 1 H),
3.54 (d, J = 12.0 Hz, 1 H), 3.64 (d, J = 12.0 Hz, 1 H), 3.99 (dt,
J = 13.0, 3.3 Hz, 1 H), 4.48 (td, J = 12.3, 1.0 Hz, 1 H), 5.56 (br s, 1
H), 7.17–7.32 (m, 5 H).
Anal. Calcd for C5H9NO3S·0.04C7H16: C, 37.93; H, 5.81; N, 8.38;
S, 19.17; Found: C, 37.75; H, 5.69; N, 8.28; S, 18.94.
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

1258
A. Estéoule et al.
SPECIAL TOPIC
13C NMR (75 MHz, CDCl3): d = 24.8, 40.4, 46.0, 48.9, 54.3, 65.2,
127.4, 128.1, 128.8, 139.5.
H), 3.73 (dtd, J = 13.3 Hz, 1 H), 3.77 (s, 3 H), 3.83 (dtd, J = 13.3
Hz, 1 H), 3.97 (dtd, J = 8.6 Hz, 1 H), 4.28 (q, J = 11.1 Hz, 1 H), 4.37
(ddd, J = 12.4, 6.0, 2.4 Hz, 1 H), 7.20–7.38 (m, 5 H).
trans-N-Benzyl-4-methyl-1,2,3-oxathiazepan-5-amine 2,2-Di-
oxide (5d)
From 4d; yield: 57%; 80% ee; white solid; mp 80–81 °C; Rf = 0.39
(CH2Cl2–MeOH–Et3N, 99:0.5:0.5); HPLC (AD column, hexane–
i-PrOH–Et3N, 95:5:0.1, flow rate: 1 mL/min, injected volume: 50
mL, detection: UV 259 nm): tR1 = 31.3 min, tR2 = 35.4 min.
13C NMR (75 MHz, CDCl3): d = 33.8, 51.0, 52.9, 59.5, 60.1, 67.4,
127.4, 128.0, 128.5, 139.2, 170.4.
cis-N-Benzyl-7-methyl-1,2,3-oxathiazepan-5-amine 2,2-Di-
oxide (cis-5h)
From cis-4h; yield: 89%; 78% ee; white solid; mp 105–106 °C;
Rf = 0.21 (heptane–EtOAc, 4:6); HPLC (OD column, hexane–
i-PrOH–Et3N, 80:20:0.1, flow rate: 1 mL/min, injected volume: 50
mL, detection: UV 265 nm): tR1 = 13.9 min, tR2 = 15.5 min.
IR (neat): 3318, 3079, 2872, 1339, 1170, 1038, 969, 745, 708 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.4 (d, J = 6.9 Hz, 3 H), 1.83 (m,
1 H), 2.27 (m, 1 H), 2.73 (m, 1 H), 3.30 (m, 1 H), 3.75 (d, J = 7.3
Hz, 2 H), 4.15 (ddd, J = 12.7, 7.4, 1.9 Hz, 1 H), 4.41 (ddd, J = 13.0,
8.5, 1.5 Hz, 1 H), 5.44 (br s, 1 H), 7.22–7.36 (m, 5 H).
13C NMR (75 MHz, CDCl3): d = 16.6, 32.1, 51.3, 52.3, 60.7, 66.0,
127.5, 126.0, 128.7, 139.5.
ESI-MS: m/z (%) = 271.1 (100) [M + H+], 293.1 (52) [M + Na+].
HRMS [ESI(+)]: m/z [M + Na+] calcd for C12H18N2O3S: 271.1116;
IR (neat): 3306, 3056, 1460, 1337, 1175, 1079, 896, 741, 696 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.44 (d, J = 6.8 Hz, 3 H), 1.82 (dt,
J = 14.7, 10.0 Hz, 1 H), 2.14 (dd, J = 15.2, 4.2 Hz, 1 H), 2.90 (m, 1
H), 3.13 (dd, J = 14.7, 9.5 Hz, 1 H), 3.34 (dd, J = 14.2, 2.6 Hz, 1 H),
3.81 (s, 2 H), 4.68 (m, 1 H), 7.26–7.39 (m, 5 H).
13C NMR (75 MHz, CDCl3): d = 22.0, 42.6, 46.2, 51.2, 56.9, 77.4,
127.4, 127.9, 128.7, 139.5.
found: 271.1121.
MS (ES+): m/z (%) = 271.1 (100) [M + H+], 293.1 (25) [M + Na+].
trans-N-Benzyl-4-ethyl-1,2,3-oxathiazepan-5-amine 2,2-Di-
oxide (5e)
From 4e; yield: 82%; 80% ee; white solid; mp 117–118 °C;
Rf = 0.33 (heptane–EtOAc, 4:6); HPLC (AD column, hexane–
i-PrOH–Et3N, 95:5:0.1, flow rate: 1 mL/min, injected volume: 15
mL, detection: UV 265 nm): tR1 = 26.7 min, tR2 = 29.7 min.
HRMS [ESI(+)]: m/z [M + H+] calcd for C12H18N2O3S: 271.1116;
found: 271.1116.
trans-N-Benzyl-7-methyl-1,2,3-oxathiazepan-5-amine 2,2-Di-
oxide (trans-5h)
From trans-4h; yield: 90%; 24% ee; colorless oil; mp 105–106 °C;
Rf = 0.42 (heptane–EtOAc, 4:6); HPLC (OD column, hexane–
i-PrOH–Et3N, 80:20:0.1, flow rate: 1 mL/min, injected volume: 50
mL, detection: UV 254 nm): tR1 = 13.5 min, tR2 = 28.3 min.
IR (neat): 3320, 3065, 2864, 1455, 1341, 1169, 1004, 920, 738, 702
cm–1.
1H NMR (300 MHz, CDCl3): d = 0.96 (t, J = 7.3 Hz, 3 H), 1.22 (br
s, 1 H), 1.62 (m, 1 H), 1.77 (m, 1 H), 1.82 (m, 1 H), 2.19 (ddq,
J = 16.0, 8.0, 1.6 Hz, 1 H), 2.74 (td, J = 6.7, 3.3 Hz, 1 H), 3.00 (m,
1 H), 3.66 (d, J = 13.0 Hz, 1 H), 3.74 (d, J = 13.0 Hz, 1 H), 4.11
(ddd, J = 13.0, 7.9, 1.7 Hz, 1 H), 4.35 (ddd, J = 13.0, 8.2, 1.9 Hz, 1
H), 5.09 (br s, 1 H), 7.16–7.30 (m, 5 H).
IR (neat): 3287, 2934, 1416, 1344, 1174, 1042, 905, 700 cm–1.
1H NMR (300 MHz, CDCl3): d = 1.36 (d, J = 6.5 Hz, 3 H), 1.42 (br
s, 1 H), 1.78 (d, J = 15.7 Hz, 1 H), 2.08 (ddd, J = 15.4, 10.3, 5.1 Hz,
1 H), 3.04 (q, J = 3.3 Hz, 1 H), 3.19 (d, J = 16.4 Hz, 1 H), 3.35 (d,
J = 15.7 Hz, 1 H), 3.71 (d, J = 12.7 Hz, 1 H), 3.81 (d, J = 12.8 Hz,
1 H), 4.92 (ddd, J = 11.0, 10.7, 5.7 Hz, 1 H), 5.77 (br s, 1 H), 7.27–
7.40 (m, 5 H).
13C NMR (75 MHz, CDCl3) : d = 10.8, 24.0, 32.8, 51.4, 59.4, 59.8,
66.5, 127.4, 128.1, 128.6, 139.7.
13C NMR (75 MHz, CDCl3): d = 21.7, 40.0, 43.1, 51.3, 53.1, 73.6,
cis-N-Benzyl-4-ethyl-1,2,3-oxathiazepan-5-amine 2,2-Dioxide
(5f)
From 4f; yield: 80%; 72% ee; yellow oil; Rf = 0.39 (CH2Cl2–
MeOH–Et3N, 99:0.5:0.5); HPLC (OD column, hexane–i-PrOH–
Et3N, 80:20:0.1, flow rate: 1 mL/min, injected volume: 50 mL, de-
tection: UV 265 nm): tR1 = 13.1 min, tR2 = 15.5 min.
127.7, 128.0, 128.8, 139.1.
MS (ES+): m/z (%) = 271.1 (100) [M + H+], 293.1 (25) [M + Na+].
HRMS [ESI(+)]: m/z [M + H+] calcd for C12H18N2O3S: 271.1116;
found: 271.1116.
IR (neat): 3290, 2965, 2358, 1422, 1346, 1175, 1004, 929, 748 cm–1.
N-Benzyl-6-Methyl-1,2,3-oxathiazepan-5-amine 2,2-Dioxide
(5i)
1H NMR (300 MHz, CDCl3): d = 1.01 (t, J = 7.0 Hz, 3 H), 1.46 (m,
1 H), 1.60 (m, 1 H), 2.04 (m, 2 H), 3.03 (t, J = 3.2 Hz, 1 H), 3.31
(dd, J = 9.2, 5.1 Hz, 1 H), 3.75 (d, J = 13.3 Hz, 1 H), 3.87 (d,
J = 13.3 Hz, 1 H), 4.10 (dt, J = 12.7, 3.2 Hz, 1 H), 4.55 (t, J = 11.7
Hz, 1 H), 5.70 (br s, 1 H), 7.28–7.39 (m, 5 H).
13C NMR (75 MHz, CDCl3): d = 11.0, 26.6, 32.8, 52.0, 55.9, 58.6,
64.6, 127.3, 128.1, 128.7, 139.5.
From 4i; yield: 79%; 68% ee (minor) and 28% ee (major diaste-
reomer); brown oil; Rf = 0.21 (CH2Cl2–MeOH–Et3N, 99:0.5:0.5);
HPLC (OD column, hexane–i-PrOH–Et3N, 80:20:0.1, flow rate: 1
mL/min, injected volume: 50 mL, detection: UV 260 nm):
tR1 (major) = 14.9 min, tR2 (major) = 28.7 min; tR1 (minor) = 17.6
min, tR2 (minor) = 22.4 min.
IR (neat): 3289, 2966, 1413, 1343, 1174, 969, 941, 790, 699 cm–1.
1H NMR (300 MHz, CDCl3): d (major) = 0.86 (d, J = 7.4 Hz, 3 H),
2.24 (m, 1 H), 2.78 (q, J = 2.8 Hz, 1 H), 3.16 (d, J = 2.8 Hz, 2 H),
3.55 (d, J = 13.4 Hz, 1 H), 3.76 (d, J = 13.3 Hz, 1 H), 3.79 (dd,
J = 10.2, 2.7 Hz, 1 H), 4.23 (dd, J = 12.4, 9.9 Hz, 1 H), 7.17–7.35
(m, 5 H); d (minor) = 1.09 (d, J = 7.2 Hz, 3 H), 1.73 (m, 1 H), 2.63
(t, J = 3.4 Hz, 1 H), 3.01 (ddd, J = 15.5, 3.9, 0.9 Hz, 1 H), 3.29 (d,
J = 15.5 Hz, 1 H), 3.63 (d, J = 12.8 Hz, 1 H), 3.73 (d, J = 12.8 Hz,
1 H), 3.85 (dd, J = 12.5, 3.6 Hz, 1 H), 4.53 (d, J = 13.3 Hz, 1 H),
5.62 (br s, 1 H), 7.17–7.35 (m, 5 H).
Methyl 5-(Benzylamino)-1,2,3-oxathiazepane-4-carboxylate
2,2-Dioxide (5g)
From 4g; yield: 78%; 62% ee; white solid; mp 121–122 °C;
Rf = 0.38 (heptane–EtOAc, 4:6); HPLC (OD column, hexane–
i-PrOH–Et3N, 80:20:0.1, flow rate: 1 mL/min, injected volume: 50
mL, detection: UV 259 nm); tR1 = 16.0 min, tR2 = 18.1 min.
IR (neat): 3321, 3040, 2876, 1731, 1433, 1349, 1182, 948, 746, 677
cm–1.
1H NMR (300 MHz, CDCl3): d = 1.96 (dtd, J = 15.5, 9.4, 3.0 Hz, 1
H), 2.27 (dtd, J = 15.5, 4.3, 1.8 Hz, 1 H), 3.12 (td, J = 8.9, 3.2 Hz, 1
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

SPECIAL TOPIC
Enantioselective Copper-Catalyzed Aziridination of Sulfamates
1259
13C NMR (CDCl3, 75 MHz): d (major) = 13.3, 37.9, 43.0, 51.2,
58.0, 69.2, 127.7, 128.1, 128.8, 139.1; d (minor) = 15.1, 38.1, 39.7,
51.2, 59.2, 69.1, 127.6, 128.0, 128.8, 139.2.
strongest 118 Friedel related reflections [>4s (DF2)] (out of a total
of 1068) were found22 to confirm the selected absolute structure,
C4(S) and C5(R).
Crystal Data: C12H16BrNO4S, FW = 350.23, data collection:21
scan frames with 1°/frame and exposure times of 12 s/frame, data
reduction:23 orthorhombic, P212121,
5.235(1) Å, b =
w
4-[(Benzylamino)methyl]-1,2,3-oxathiazepane 2,2-Dioxide (5j)
From 4j; 67% yield; 47% ee; white solid; mp 103–104 °C; Rf = 0.10
(CH2Cl2–MeOH–Et3N, 99:0.5:0.5); HPLC (OD column, hexane–
i-PrOH–Et3N, 80:20:0.1, flow rate: 1 mL/min, injected volume: 50
mL, detection: UV 265 nm): tR1 = 10.5 min, tR2 = 12.7 min.
a
=
11.884(1) Å, c = 23.666(2) Å, V = 1472.36(6) Å3, D = 1.580 Mg/
m3, 12053 collected reflections up to qmax = 25.4°, 2668 unique
(Rint = 0.0598), structure solution:24 direct methods, model refine-
ment:24 on sF2 by full-matrix least-squares methods with anisotro-
pic thermal parameters for all non-hydrogen atoms, all hydrogen
atoms were located on difference Fourier syntheses but were refined
with a riding model and with Uiso (H) = 1.2 Ueq (C) (1.5 for a
methyl group), R1 = 0.0655, wR2 = 0.1029 [R1 = 0.0405, wR2 =
0.0913 for I > 2s (I)], goodness-of-fit = 1.064, Flack para-
meter = 0.001(15).
IR (neat): 3283, 3024, 2850, 1451, 1342, 1175, 1013, 940, 750, 700
cm–1.
1H NMR (300 MHz, CDCl3): d = 1.67 (q, J = 11.2 Hz, 1 H), 1.93
(m, 1 H), 1.96 (m, 1 H), 2.03 (m, 1 H), 2.69 (dd, J = 22.5, 12.5 Hz,
1 H), 2.70 (dd, J = 20.3, 12.7 Hz, 1 H), 3.27 (br s, 2 H), 3.47 (m, 1
H), 3.76 (d, J = 13.1 Hz, 1 H), 3.83 (d, J = 13.1 Hz, 1 H), 4.29 (m,
2 H), 7.24–7.38 (m, 5 H).
Structural data have been deposited with the Cambridge Crystallo-
graphic Data Centre (CIF file) as supplementary publication num-
ber CCDC 635135. Copies of the data can be obtained free of
charge, on application to CCDC, 12 Union Road, CB2 1EZ, UK
[fax:+44(1223)336033, e-mail: deposit@ccdc.cam.ac.uk].
13C NMR (75 MHz, CDCl3): d = 27.7, 32.5, 52.7, 52.8, 53.6, 70.8,
127.5, 128.4, 128.8, 139.7.
(4S,5R)-5-[(4-Bromobenzyl)oxy]-4-methyl-1,2,3-oxathiazepane
2,2-Dioxide (6)
BF3·OEt2 (78 mL, 0.6 mmol, 0.1 equiv) and PBBOH (1.4 g, 7.4
mmol, 1.2 equiv) were added to a soln of 4d (1 g, 6.1 mmol, 1 equiv)
in CH2Cl2 (20 mL) at 0 °C under argon. The mixture was stirred at
20 °C for 7 h. The reaction was quenched with 10% aq NaHCO3 (40
mL) and the layers were separated. The aqueous layer was extracted
with CH2Cl2 (3 × 40 mL) and the combined organic layers were
dried (MgSO4). The solvent was removed under reduced pressure;
this gave the crude product, which was filtered over silica gel
(CH2Cl2). The resulting white solid [yield: 55% (by 1H NMR); 80%
ee (by chiral HPLC)] was purified by recrystallization (MeOH). A
white crystalline solid was obtained (0.47 g), while a second crop
(0.34 g) was obtained from the mother liquor.
Total yield: 0.81 g (38%); >99% ee; mp 63–64 °C; [a]D20 –12.25 (c
0.52, CHCl3); Rf = 0.42 (heptane–EtOAc, 6:4); HPLC (OD column,
hexane–i-PrOH–Et3N, 90:10:0.1, flow rate: 1 mL/min, injected
volume: 50 mL, detection: UV 265nm): tR1 [(4R,5S)-6] = 22.3 min,
tR2 [(4S,5R)-6] = 27.4 min.
Acknowledgment
We thank the Institut de Chimie des Substances Naturelles for fi-
nancial support and a fellowship (A.E.). The support and sponsor-
ship from COST Action D24 ‘Sustainable Chemical Processes:
Stereoselective Transition Metal-Catalyzed Reactions’ are kindly
acknowledged.
References
(1) For representative overviews of aziridine chemistry, see:
(a) Tanner, D. Angew. Chem., Int. Ed. Engl. 1994, 33, 599.
(b) Zwanenburg, B.; ten Holte, P. Top. Curr. Chem. 2001,
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(d) Aziridines and Epoxides in Organic Synthesis; Yudin, A.
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Prakt. Chem. 1999, 341, 319. (b) McCoull, W.; Davis, F. A.
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(4) (a) Dauban, P.; Dodd, R. H. Synlett 2003, 1571. (b) Müller,
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Yu, L.; Yudin, A. K. Acc. Chem. Res. 2006, 39, 194.
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IR (neat): 3291, 2965, 1434, 1340, 1170, 1125, 1103, 966, 805, 720
cm–1.
1H NMR (300 MHz, CDCl3): d = 1.41 (d, J = 6.8 Hz, 3 H), 2.03 (m,
1 H), 2.23 (ddt, J = 15.9, 9.0, 2.6 Hz, 1 H), 3.43 (m, 2 H), 4.17 (ddd,
J = 13.1, 7.1, 2.2 Hz, 1 H), 4.43 (d, J = 12.2 Hz, 1 H), 4.46 (m, 1 H),
4.54 (d, J = 12.2 Hz, 1 H), 5.09 (d, J = 4.7 Hz, 1 H), 7.16 (d, J = 8.7
Hz, 2 H), 7.47 (d, J = 8.4 Hz, 2 H).
13C NMR (75 MHz, CDCl3): d = 16.10, 31.04, 52.79, 65.70, 70.70,
79.76, 122.03, 129.34, 131.76, 136.42.
ESI-MS: m/z (%) = 371.9 (99.8) [M + Na+], 373.9 (100) [M + Na+].
HRMS [ESI(+)]: m/z [M + Na+] calcd for C12H1679BrNO4S:
371.9881; found: 371.9891; m/z [M
+
Na+] calcd for
C12H1681BrNO4S: 373.9861; found: 373.9872.
X-ray Crystal Structure Determination of Compound 6
Reflection data were collected on a Nonius-Bruker Kappa CCD dif-
fractometer with graphite-monochromated Mo–Ka radiation
(l = 0.71073 Å). Reflection data were collected according to the
Friedel strategy21 to minimize errors in the Bijvoet differences ow-
ing to the bromide atom in the molecule and to optimize the discrim-
inating power between the enantiomeric structures. All of the
(5) (a) Abramovitch, R. A.; Bailey, T. D.; Takaya, T.; Uma, V.
J. Org. Chem. 1974, 39, 340. (b) Yamada, Y.; Yamamoto,
T.; Okawara, M. Chem. Lett. 1975, 361.
Synthesis 2007, No. 8, 1251–1260 © Thieme Stuttgart · New York

1260
A. Estéoule et al.
SPECIAL TOPIC
(6) For some representative examples, see: (a) Evans, D. A.;
Faul, M. M.; Bilodeau, M. T. J. Am. Chem. Soc. 1994, 116,
2742. (b) Södergren, M. J.; Alonso, D. A.; Bedekar, A. V.;
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(c) Dauban, P.; Dodd, R. H. J. Org. Chem. 1999, 64, 5304.
(d) Kwong, H.-L.; Liu, D.; Chan, K.-Y.; Lee, C.-S.; Huang,
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(e) Han, H.; Bae, I.; Yoo, E. J.; Lee, J.; Do, Y.; Chang, S.
Org. Lett. 2004, 6, 4109. (f) Mohr, F.; Binfield, S. A.;
Fettinger, J. C.; Vedernikov, A. N. J. Org. Chem. 2005, 70,
4833.
(7) For representative examples, see: (a) Müller, P.; Baud, C.;
Jacquier, Y. Tetrahedron 1996, 52, 1543. (b) Guthikonda,
K.; Du Bois, J. J. Am. Chem. Soc. 2002, 124, 13672.
(c) Liang, J.-L.; Yuan, S.-X.; Hong Chan, P. W.; Che, C.-M.
Org. Lett. 2002, 4, 4507. (d) Padwa, A.; Flick, A. C.;
Leverett, C. A.; Stengel, T. J. Org. Chem. 2004, 69, 6377.
(e) Keaney, G. F.; Wood, J. L. Tetrahedron Lett. 2005, 46,
4031. (f) Catino, A. J.; Nichols, J. M.; Forslund, R. E.;
Doyle, M. P. Org. Lett. 2005, 7, 2787. (g) Hayes, C. J.;
Beavis, P. W.; Humphries, L. A. Chem. Commun. 2006,
4501.
(8) For recent examples, see: (a) Davies, H. M. L.; Long, M. S.
Angew. Chem. Int. Ed. 2005, 44, 3518. (b) Liang, C.;
Robert-Peillard, F.; Fruit, C.; Müller, P.; Dodd, R. H.;
Dauban, P. Angew. Chem. Int. Ed. 2006, 45, 4641. (c)Fiori,
K. W.; Du Bois, J. J. Am. Chem. Soc. 2007, 129, 562.
(9) For recent examples, see: (a) White, R. D.; Keaney, G. F.;
Slown, C. D.; Wood, J. L. Org. Lett. 2004, 6, 1123.
(b) Provoost, O. Y.; Hedley, S. J.; Hazelwood, A. J.; Harrity,
J. P. A. Tetrahedron Lett. 2006, 47, 331. (c) Trost, B. M.;
Dong, G. J. Am. Chem. Soc. 2006, 128, 6054. (d) Kessler,
A.; Faure, H.; Petrel, C.; Rognan, D.; Césario, M.; Ruat, M.;
Dauban, P.; Dodd, R. H. J. Med. Chem. 2006, 49, 5119.
(10) Rhodium-catalyzed nitrene transfer has found application in
total synthesis in the field of C–H amination. Impressive
examples of syntheses of highly complex natural products
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