Asymmetric transfer of nitrenes catalyzed by chiral dirhodium(II) using aromatic sulfamate esters

Article abstract of DOI:10.1016/j.tetasy.2004.01.015

Enantioselective intra- and intermolecular insertions of aromatic sulfamate esters into activated C-H bonds have been achieved via in situ generated phenyliodinanes in the presence of PhI(OAc)₂, MgO, and chiral Rh(II) catalysts. The optimal results were obtained with [Rh ₂{(S)-nttl}₄] and [Rh₂{(R)-ntv}₄] as catalysts with up to 52% ee. In contrast, phenylsulfamates with allylic ortho-substituents reacted via intramolecular aziridination rather than insertion. The intermolecular amidation of indane proceeded with up to 97% yield when the reaction was carried out with the sulfamate in excess.

Full text of DOI:10.1016/j.tetasy.2004.01.015

Tetrahedron:
Asymmetry
Tetrahedron: Asymmetry 15 (2004) 1019–1026
Asymmetric transfer of nitrenes catalyzed by chiral dirhodium(II)
using aromatic sulfamate esters
*
€
Corinne Fruit and Paul Muller
Department of Organic Chemistry, University of Geneva, 30, Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
Received 19 December 2003; accepted 15 January 2004
Abstract—Enantioselective intra- and intermolecular insertions of aromatic sulfamate esters into activated C–H bonds have been
achieved via in situ generated phenyliodinanes in the presence of PhI(OAc)2, MgO, and chiral Rh(II) catalysts. The optimal results
were obtained with [Rh2{(S)-nttl}4] and [Rh2{(R)-ntv}4] as catalysts with up to 52% ee. In contrast, phenylsulfamates with allylic
ortho-substituents reacted via intramolecular aziridination rather than insertion. The intermolecular amidation of indane proceeded
with up to 97% yield when the reaction was carried out with the sulfamate in excess.
Ó 2004 Elsevier Ltd. All rights reserved.
1. Introduction
with PhI(OAc)2 could be used directly as nitrene sources
in Cu(I)-8 and Rh(II)-9;10catalyzed nitrene transfer. The
decomposition of phenyliodonium ylides 2 derived from
sulfamates 1 in the presence of catalysts results in the
synthesis of cyclic sulfamidates 3, which are versatile
reagents in organic synthesis (Scheme 1).11 This class of
compound is of interest for the synthesis of various
products possessing heteroatomic functional groups.
They are useful precursors for the preparation of amino-
acid derivatives,12 piperazines or thiomorpholines,13
amino alcohols,14 oligosaccharides,15 glyco-peptides,16
or indolizidine derivatives.17
Insertion into C–H bonds is a reaction characteristic for
carbenes and has found numerous applications in
asymmetric catalysis.1 Nitrenes may insert into satu-
rated CH bonds by analogy. Nitrene transfer reactions,
usually based on transition metal-catalyzed decomposi-
tion of sulfonylimino phenyliodinanes, constitute pow-
erful methodologies for C–N bond formation2 and,
consequently, for the synthesis of amines derivatives.
The catalytic nitrene transfer became feasible once the
appropriate nitrogen precursors became available.
Originally, only sulfonyliminoiodinanes derived from
aromatic sulfonamides were available.3 More recently,
through a variety of aliphatic and functionalized sulfo-
nyliminoiodinanes have been synthesized and used for
catalyzed nitrene transfer reactions.4 The Rh(II)-cata-
lyzed intermolecular insertion5 or aziridination6 with
sulfonyl iminoiodinanes has been investigated in some
detail by our group. Intermolecular amidation of C–H
bonds was also realized recently by Che and Hashimoto,
respectively, using chiral dirhodium catalysts.7
R
O
IPh
O
SO2NH2
H
N
S
O
PhI(OAc)2, MgO
O
R'
R
R''
H
1
R'
R
O
SO2
R''
Rh2L*4
NH
R'
2
R''
A breakthrough occurred recently, when Dauban and
Du Bois independently found that iminophenyliodin-
anes could be generated and catalytically decomposed in
situ, so that their isolation became unnecessary. Sul-
fonamides, carbamates, or sulfamates in conjunction
3
Scheme 1.
Recently, Che described a one pot process for intra-
molecular amidation of sulfamates esters, using iodo-
benzene
diacetate/Al2O3,
catalyzed
by
chiral
* Corresponding author. Tel.: +41-22-379-6515; fax: +41-22-379-3215;
e-mail: corinne.fruit@chiorg.unige.ch
ruthenium(II) porphyrins.18 Sulfamidates were obtained
0957-4166/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetasy.2004.01.015

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C. Fruit, P. M€uller / Tetrahedron: Asymmetry 15 (2004) 1019–1026
in a highly diastereoselective manner, and with enan-
tiomeric excesses in the range of 46–87% with a catalyst
load of 10 mol %. Asymmetric nitrene transfer using
sulfamates with chiral dirhodium(II) catalysts has not
been systematically investigated so far, although these
reactions appear to have substantial potential.
The enantioselective amidation was first examined with
sulfamate ester 5a as the substrate and [Rh2{(R)-ntv}4]
as catalyst. Reaction of 5a in the presence of 3.5 mol %
of catalyst, afforded cyclic sulfamidate 6a in 75% yield.
With 2.0 and 0.5 mol % of [Rh2{(R)-ntv}4], the yield of
6a dropped to 62% and 45%, respectively. CH2Cl2 was
superior to PhCl, MeCN, and pentane. In these latter
three solvents, the yield of 6a decreased significantly to
45%, 32%, and 38%, respectively. No significant
enantioselectivity was induced by [Rh2{(R)-ntv}4]
(Table 1).
2. Results and discussion
2.1. Intramolecular amidation catalyzed by chiral dirho-
dium(II) complexes
Several dirhodium(II) catalysts were then examined in
the intramolecular amidation, mostly with 5b and 5c
(Table 2). The rhodium carboxamidates, [Rh2{(5S)-
mepy}4] or Rh2{4S)-meox}4] were less efficient than
rhodium carboxylate catalysts for nitrene transfer and
longer reaction times were required. In addition, rho-
dium carboxamidates led to no enantioselectivity. The
proline-derived rhodium carboxylate (Rh2{(S)-dosp}4]
produced a slight induction (around 20% for com-
pounds 6b and 6c), while the Hashimoto-type catalyst
[Rh2{(S)-ptpa}4] was unselective. However, encouraging
results were obtained with [(Rh2{(S)-nttl}4], a catalyst
recently introduced by our group, which uses the 1,8-
Following the pioneering work of Du Bois and
co-workers,9;10 we explored the in situ generation and
Rh(II)-catalyzed decomposition of imino phenyliodin-
anes derived from aromatic sulfamates esters. The
sulfamate precursors were synthesized from the corre-
sponding phenols using in situ generated sulfamoyl
chloride,19 and obtained with yields in the range of 67–
87% (see Experimental). Treatment of the sulfamates
5a–d with PhI(OAc)2 (1.5 equiv)/MgO (2.5 equiv) in
dichloromethane in the presence of [Rh2(OAc)4] afford-
ed the cyclic sulfamidates 6a–d with yields in the range
of 24–79%. Insertion into 5a proceeded with a slightly
lower yield than with the benzyl derivatives 5b and 5c,
but the methoxy compound 5d afforded only a low yield
of 24% of 6d (Table 1, Scheme 2).
naphthalimide of
L
-tert-leucine as a bridging ligand.20
With this catalyst, substrate 5c was the most effective
and afforded eeÕs of 49% at 40 °C and 52% at )78 °C.
Table 2. Intramolecular amidation catalyzed by Rh(II) complexesa
Table 1. Intramolecular nitrene insertion with 5a–da
Compound Catalyst
T
(°C)
t
(h)
Yield Ee
(%)
(%)
Compound Catalyst
Solvent
t
(h)
Yield
(%)
Ee
(%)
5b
5c
5a
5b
5a
5b
5c
5a
5b
5b
5c
5c
5c
5b
5c
5b
5c
[Rh2{(5S)-mepy}4]
40
40
7.5
57
29
38
70
60
68
80
38
82
77
90
84b
68
77
76
74
78
<5
11
<5
<5
<5
<5
<5
32
31
38
49
42
52
13
28
20
18
[Rh2{(5S)-mepy}4]
[Rh2{(4S)-meox}4]
[Rh2{(4S)-meox}4]
[Rh2{(S)-ptpa}4]
[Rh2{(S)-ptpa}4]
[Rh2{(S)-ptpa}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-nttl}4]
[Rh2{(R)-ntv}4]
[Rh2{(R)-ntv}4]
[Rh2{(S)-dosp}4]
[Rh2{(S)-dosp}4]
7.5
6
5a
5b
5c
5d
5a
[Rh2(OAc)4]
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
6
2
2
3
6
61
77
79
24
75
––
––
––
––
<5
40
40
[Rh2(OAc)4]
[Rh2(OAc)4]
[Rh2(OAc)4]
[Rh2{(R)-ntv}4],
3.5%
3.5
6
40
40
2
40
2
13
)78
40
5a
5a
[Rh2{(R)-ntv}4],
2%
CH2Cl2
CH2Cl2
6
6
62
45
<5
<5
2
4
2
2
8
2
2
2
2
)20
40
[Rh2{(R)-ntv}4],
0.5%
40
5a
5a
5a
[Rh2{(R)-ntv}4]
[Rh2{(R)-ntv}4]
[Rh2{(R)-ntv}4]
PhCl
MeCN
C5H12
21
6
45
32
38
<5
<5
<5
)78
40
6
40
40
a With 3.5% of catalyst, at 40 °C, unless indicated otherwise.
40
a Standard conditions, 3.5 mol % of catalyst; see Experimental.
b Reaction performed with 2% of catalyst.
OSO2NH2
R
NH2SO2Cl
NMP, 0°C
OH
R
X
then rt, 3.5h
X
The positive results with [(Rh2{(S)-nttl}4] contrast
markedly from those obtained with [Rh2{(R)-ntv}4],
which uses the 1,8-naphthalimide of D-valine as the
4a-d
5a-d
ligand. These catalysts, which differ only by an addi-
tional methyl group adjacent to the stereogenic center,
produce enantiomeric products with practically the
same degree of enantioselectivity in intermolecular car-
bene transfer reactions.21 Replacement of the para-
chloro substituent of 5c by H, that is 5b, resulted in a
decrease in selectivity from 49–31% (at 40 °C) (Chart 1).
O
Rh2L*4
SO2
a X = H,
b X = H,
R = Me
R = Ph
NH
PhI(OAc)2
MgO
X
c X = Cl, R = Ph
d X = OMe, R = Ph
R
6a-d
Scheme 2.

C. Fruit, P. M€uller / Tetrahedron: Asymmetry 15 (2004) 1019–1026
1021
O
O
O
X
R
Rh2L*4
PhI(OAc)2, MgO
S
N
H
OSO2NH2
O
N
O
N
H
COOMe
H
COOH
O
CH2Cl2
X = CH2 : [Rh2{(5S)-mepy}4]
X = O : [Rh2{(4S)-meox}4]
a X = H
X
b X = F
R = CH2Ph : [Rh2{(S)-ptpa}4]
X
c X = OMe
7
8
O
R
N
O
S
N
R
Scheme 3.
H
O
HOOC
COOH
H
O
result with 30% ee. Surprisingly, the dirhodium carbox-
amidates, such as [Rh2{(4S)-meox}4] or [Rh2{(5S)-
mepy}4] resulted in the highest enantioselectivities,
although the yields of the aziridines were slightly lower
than with carboxylate catalysts. This result is consistent
with those reported by Che, who found enantioselec-
tivities of up to 49% and 76% using, respectively,
[Rh2{(5S)-mepy}4]7a and [Rh2{(4S)-meox}4]7c as cata-
lysts in intramolecular aziridinations using N-aryl-
sulfonyliminoiodinane PhINSO2Ar as the nitrene
precursor. The para-methoxy derivative 7c afforded
higher enantioselectivity than the para-fluoro derivative
7b, but afforded a lower yield of aziridine 8.
R = C12H25 : [Rh2{(S)-dosp}4]
R = t-Bu : [Rh2{(S)-nttl}4]
R = Me2CH: [Rh2{(R)-ntv}4]
Chart 1. Ligands and abbreviations of Rh(II) catalysts.
2.2. Intramolecular aziridination catalyzed by chiral
dirhodium complexes
The 2-allyl substituted sulfamates 7a–c failed to undergo
insertion, but reacted exclusively via intramolecular
aziridination instead. The same chiral Rh(II) catalysts
were screened for the aziridination under standard
conditions. Chiral Rh(II) catalysts were screened under
standard condition with aromatic sulfamate esters 7a–c
as substrates (Table 3, Scheme 3).
2.3. Intermolecular amidation
While intermolecular catalytic aziridination of olefins
with sulfonamide precursors is well known, the analo-
gous intermolecular nitrene insertions with sulfamate
precursors have not yet been reported.22 We have car-
ried out some exploratory reactions with indane 9 as
substrate and 10 in the presence of [Rh2(OAc)4] in dif-
ferent solvents and with changing the indane/sulfamate
ratio (Table 4). When the reagents were used in a 1:1
ratio, the reaction proceeded with 46% yield in CH2Cl2
(Scheme 4).
Table 3. Enantioselective intramolecular aziridination by dirho-
dium(II) complexesa
Compound Catalyst
t (h)
Yield (%) Ee (%)
7a
7b
7c
7a
7a
[Rh2(OAc)4]b
1.5
2
62
60
58
32
10
––
––
––
50
52
[Rh2(OAc)4]b
[Rh2(OAc)4]b
3
[Rh2{(5S)-mepy}4]
[Rh2{(5S)-
mepy}4]c
5.5
9.5
7b
7c
7a
7b
7c
7a
7b
7c
7a
7b
7c
7a
7b
7c
7b
[Rh2{(5S)-mepy}4]
[Rh2{(5S)-mepy}4]
[Rh2{(4S)-meox}4]
[Rh2{(4S)-meox}4]
[Rh2{(4S)-meox}4]
[Rh2{(S)-ptpa}4]
[Rh2{(S)-ptpa}4]
[Rh2{(S)-ptpa}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-nttl}4]
[Rh2{(R)-ntv}4]
[Rh2{(R)-ntv}4]
[Rh2{(R)-ntv}4]
[Rh2{(S)-dosp}4]
4
63
18
55
51
23
79
70
53
68
72
36
63
75
64
80
17
39
18
21
24
30
19
27
19
15
22
15
7
Table 4. Optimization of intermolecular amidation of indane 9a
7
Entry
9/10
Solvent
t (h)
Yield (%)b
5.5
4
1
1/1
1/1
CH2Cl2
6.5
10
10
8.5
8.5
8.5
6.5
6.5
9.5
8
46
54
––
12
12
13
70
68
75
56
46
52
7
2
CH2Cl2/5% sulfolane
Pentane
CH3 CN
2
3
1/1
1/1
1.5
3
4
5
1/1
1/1
PhCH3
PhCF3
1.5
1.5
3
6
7
5/1
CH2Cl2
CH2Cl2
8
10/1
1/2
2
9
CH2Cl2
CH2Cl2
1.5
3
10
11
12
1/1.5
1/1.2
1/1.2
15
<5
CH2Cl2
CH2Cl2/5% sulfolane
8
1.5
8
a Reactions carried out in CH2Cl2 with 3.5 mol % of catalyst (see
a Conditions: at 40 °C, with 5 mol % of [Rh2(OAc)4].
Experimental part).
b 5% of catalyst.
c )20 °C.
b Yield calculated with respect to limiting reagent.
Addition of 5% of sulfolane resulted in an increase to
54%. Other solvents, such as pentane and toluene were
inappropriate. The yield of insertion product 11
increased to 70% and 68%, respectively, with a five- or
tenfold excess of indane. Interestingly, the yield of 11
increased to 75% when reagent 10 was used in twofold
Although rhodium carboxylates were efficient for
aziridination, the catalysts showed only modest enanti-
oselectivities. HashimotoÕs tetrakis[N-phthaloyl-(S)-
phenylalaninate], [Rh2{(S)-ptpa}4], gave the optimal

1022
C. Fruit, P. M€uller / Tetrahedron: Asymmetry 15 (2004) 1019–1026
purification. Flash chromatography (FC): silica gel 32-
ꢀ
63 60 A Merck 9385. TLC: Macherey-Nagel Polygram
Rh2L*4
PhI(OAc)2, MgO
Sil/UV254; detection by UV light. The enantiomeric
excess of the products was determined by GC (b-Dex
columns) or by HPLC (chiracel OD-H or AD-H); tR in
minutes. IR spectra: Mattson instruments Polaris FT-IR
instrument, NaCl cells, in cmꢀ1; NMR spectra: Bruker
AMX-300, chemical shifts d in ppm with respect to
SiMe4 ( ¼ 0 ppm), coupling constants in Hz. MS: Varian
CH4 or SM1 spectrometer with electron impact or
electrospray; m=z (rel %). High resolution (HR) MS:
VG-7070 analytical spectrometer (data system 11 250,
resolution 7000).
O
NH2
SO2
N
O
O
O
S
10
9
11
Scheme 4.
excess over 9. This observation is of interest in view of
synthetic applications of the reaction, and contrasts with
that made in Rh(II)-catalyzed CH insertions with phenyl-
iodinanes derived from aromatic sulfonamides, where
an excess of reagent does not lead to higher yields.5
4.2. Preparation of aryl sulfamate esters. Typical proce-
dure
A 100 mL two necked round bottom flask fitted with a
reflux condenser, dropping funnel, and under argon
atmosphere, was charged with chlorosulfonyl isocyanate
(3.5 mL, 40 mmol, 2.0 equiv) at 0 °C. Anhydrous formic
acid (1.5 mL, 40 mmol, 2.0 equiv) was added dropwise
with rapid stirring. The mixture was stirred at room
temperature until gas evolution ceased (from 1 to 4 h).
To the resulting sulfamoyl chloride was added a solution
of alcohol (20 mmol) in 30 mL of 1-methyl-2-pyrrol-
idone under ice-cooling over 30 min dropwise. The
reaction mixture was stirred at room temperature for 3 h
(yellow-orange solution). The resulting mixture was
poured into cold brine (100 mL) and washed twice with
ethyl acetate (150 mL). The combined organic extracts
were dried over magnesium sulfate and concentrated
under reduced pressure. Purification of the residue by
flash chromatography on silica gel using pentane/ethyl
acetate as eluent afforded the desired sulfamate ester.
So far, the enantioselectivities reached in these reactions
are modest and do not exceed 30% (Table 5). On the
other hand, the yields of isolated insertion product 11
are encouraging.
Table 5. Enantioselective amidation of indane with sulfamate 10 cat-
alyzed by dirhodium(II) complexesa
Entry
Rh2Lꢁ
t (h)
Yield (%)
Ee (%)
4
1
2
3
[Rh2{(S)-ptpa}4]
[Rh2{(S)-nttl}4]
[Rh2{(S)-ptpa}4]
9.5
9.5
9.5
79b
82b
97
18
27
30
a In refluxing CH2Cl2 with twofold excess of 10 and 2.5 mol % of
catalyst.
b With 5% of sulfolane as co-solvent.
3. Conclusion
In summary, we have reported the first intra- and inter-
molecular amidation reaction using aromatic sulfamate
ester and chiral rhodium catalyst. We have demon-
strated that [Rh2{(S)-nttl}4] developed in our group is
the most effective catalyst for enantioselective amidation
of C–H bonds (ee up to 52%). Selective intramolecular
aziridination of a 2-allyl arylsulfamate 7 has been
achieved using chiral dirhodium complexes without
observing competitive C–H bond insertion. These azir-
idinations proceeded with up to 52% ee with carbox-
amidate ligands such as [Rh2(S-mepy)4]. Finally, the
intermolecular CH insertion of indane with an aryl
sulfamate in twofold excess has been realized in high
yield, albeit with modest enantioselectivity with Rh(II)-
carboxylate catalysts.
4.2.1. 2-Ethylphenylsulfamate 5a. Prepared from 2-ethyl-
phenol 4a (2.37 mL) according to the general method
and purified by flash chromatography on silica gel
(pentane/EtOAc, 3:1). Colorless solid (3.50 g, 87%): mp
67 °C; TLC Rf ¼ 0:50. IR (neat): 3267, 2969, 1647, 1371,
1186, 1157, 1108, 864, 777 cmꢀ1 1H NMR (CDCl3,
.
300 MHz): 1.27 (t, 3H, J ¼ 7:5 Hz), 2.80 (q, 2H,
J ¼ 7:5 Hz), 5.36 (br, 2H), 7.23–7.38 (m, 4H). 13C NMR
(CDCl3, 75 MHz): 14.2 (CH3), 23.0 (CH2), 121.7 (CH),
127.1 (CH), 127.4 (CH), 130.1 (CH), 137.1 (C), 148.3
(C). HR MS: 201.04724 (C8H11NO3Sþ; calcd
201.04597).
4.2.2. 2-Benzylphenylsulfamate 5b. Prepared from 2-hy-
droxydiphenylmethane 4b (3.68 g) according to the
general method and purified by flash chromatography
on silica gel (pentane/EtOAc, 3:1). Colorless solid
(3.67 g, 70%). Mp 110 °C; TLC Rf ¼ 0:50. IR (neat):
3391, 3278, 1450, 1348, 1157, 1090, 931, 886, 862,
4. Experimental part
4.1. General23
1
All reactions were carried out under an inert atmosphere
(argon). CH2Cl2, MeCN, toluene, and chlorobenzene
were dried over CaH2 and distilled. The other solvents
were purchased from Fluka or Acros and used without
776 cmꢀ1. H NMR (CDCl3, 300 MHz): 4.11 (s, 2H),
4.34 (br, 2H), 7.26–7.37 (m, 8H), 7.51 (m, 1H). 13C
NMR (CDCl3, 75 MHz): 36.6 (CH2), 121.6 (CH), 126.6
(CH), 127.2 (CH), 128.1 (CH), 128.7 (CH), 129.2 (CH),

C. Fruit, P. M€uller / Tetrahedron: Asymmetry 15 (2004) 1019–1026
1023
1
131.7 (CH), 133.8 (C), 140.2 (C), 148.9 (C). HR MS:
263.06212 (C13H13NO3Sþ; calcd 263.06162).
2921, 1739, 1435, 1366, 1217 cmꢀ1. H NMR (CDCl3,
300 MHz): 3.53 (d, 2H, J ¼ 6:4 Hz), 5.11 (m, 1H), 5.17
(m, 1H), 5.28 (br, 2H), 5.92–6.06 (m, 1H), 7.28 (m, 3H),
7.43 (m, 1H). 13C NMR (CDCl3, 75 MHz): 34.2 (CH2),
116.8 (CH2), 121.9 (CH), 127.3 (CH), 127.8 (CH), 131.1
(CH), 133.0 (C), 136.2 (CH), 148.4 (C). MS (EI): 213
(Mþ, 39), 133 (100), 105 (87), 77 (51), 51 (25). HR MS
213.04466 (C9H11NO3Sþ; calcd 213.04597).
4.2.3. 2-Benzyl-4-chlorophenylsulfamate 5c.
Prepared
from 2-benzyl-4-chlorophenol (5.66 g) according to the
general method and purified by flash chromatography
on silica gel (pentane/EtOAc, 3:1). Colorless solid
(4.16 g, 70%). Mp 77 °C; TLC Rf ¼ 0:44. IR (neat):
3396, 3283, 3029, 1738, 1494, 1475, 1374, 1193, 1155,
1105, 911, 828, 740, 699 cmꢀ1
.
1H NMR (CDCl3,
4.2.6. 2-Allyl-4-fluorophenylsulfamate 7b. Prepared from
2-allyl-4-fluorophenol26 (3.04 g) according to the general
method and purified by flash chromatography on silica
gel (pentane/EtOAc, 3:1), was obtained as a cream solid
(3.49 g, 75%), mp 78 °C; TLC Rf ¼ 0:60. IR (neat): 3013,
300 MHz): 4.06 (s, 2H), 5.09 (br, 2H), 7.21–7.41 (m, 8H).
13C NMR (CDCl3, 75 MHz): 36.1 (CH2), 123.1 (CH),
126.8 (CH), 127.9 (CH), 128.8 (CH), 129.2 (CH), 131.3
(CH), 132.6 (C), 136.1 (C), 139.1 (C), 141.1 (C). HR MS:
297.02264 (C13H12ClNO3Sþ; calcd 297.02272).
1
2970, 1739, 1438, 1366, 1217 cmꢀ1. H NMR (CDCl3,
300 MHz): 3.50 (d, 2H, J ¼ 6:6 Hz), 5.13–5.20 (m, 2H),
5.35 (br, 2H), 5.87–6.01 (m, 1H), 6.92–7.03 (m, 2H), 7.38
(m, 1H). 13C NMR (CDCl3, 75 MHz): 34.1 (CH2), 114.2
(CH), 114.5 (CH), 117.3 (CH), 117.5 (CH2), 123.4 (CH),
123.5 (CH), 135.1 (CH), 135.6 (C), 144.1 (C), 158.3 (C).
19F NMR (CDCl3, 282 MHz): )114.2 (CFCl3). MS: 231
(Mþ, 100), 151 (100), 123 (75), 103 (78), 77 (39), 51 (18).
HR MS: 231.03448 (C9H10FNO3Sþ; calcd 231.03654).
4.2.4. 2-Benzyl-4-methoxyphenyl sulfamate 5d. 2-Benzyl-
4-methoxyphenol 4d.24 4-Methoxy-phenol (12.41 g,
100 mmol) was added gradually to a stirred suspension
of sodium hydride (60%, 4.0 g, 100 mmol) in toluene
(150 mL) under nitrogen. To the resulting suspension,
stirred and maintained at gentle reflux, was added ben-
zyl chloride (12.6 mL, 110 mmol) dropwise. After 5 h of
vigorous refluxing, the reaction mixture was cooled and
hydrolyzed with dilute hydrochloric acid. The aqueous
layer was separated and the toluene washed with water
and then sodium hydrogen carbonate. The toluene
solution was then extracted several times with aq so-
dium hydroxide. The basic extracts were acidified with
hydrochloric acid and the liberated phenolic material
taken up in ether. Concentration under reduced pressure
gave 2-benzyl-4-methoxy-phenol (9.77 g, 45%) as a pale
brown solid, mp 104 °C. IR (neat): 3309, 3029, 2959,
4.2.7. 2-Allyl-4-methoxyphenylsulfamate 7c.
Prepared
from 2-allyl-4-methoxyphenol27 (1.39 g, 8.5 mmol)
according to the general method (chlorosulfonyl iso-
cyanate (1.5 mL, 17 mmol, 2.0 equiv) and formic acid
(0.64 mL, 17 mmol, 2.0 equiv)) and purified by flash
chromatography on silica gel (pentane/EtOAc, 2.5:1)
and was obtained as a pale yellow oil (1.54 g, 75%); TLC
Rf ¼ 0:54. IR (neat): 3380. 3277, 2938, 1744, 1491, 1370,
1190, 1161, 1029, 911, 841, 728 cmꢀ1. 1H NMR (CDCl3,
300 MHz): 3.48 (d, 2H, J ¼ 6:4 Hz), 3.80 (s, 3H), 5.13
(m, 1H), 5.16 (m, 1H), 5.34 (br, 2H), 5.91–6.01 (m, 1H),
7.76 (m, 1H), 6.80 (m, 1H), 7.30 (d, 1H, J ¼ 8:7 Hz). 13C
NMR (CDCl3, 75 MHz): 34.3 (CH2), 55.6 (OCH3),
112.5 (CH), 115.9 (CH), 116.9 (CH2), 123.0 (CH), 134.5
(C), 135.9 (CH), 142.0 (C), 158.1 (C). HR MS:
243.05780 (C10H13NO4Sþ; calcd 243.05653).
2830, 1599, 1505, 1435, 1209, 1035, 798, 723, 693 cmꢀ1
.
1H NMR (CDCl3, 300 MHz): 3.82 (s, 3H), 4.07 (s, 2H),
5.43 (br, 1H), 6.76–6.87 (m, 3H), 7.30–7.39 (m, 5H). 13C
NMR (CDCl3, 75 MHz): 36.5 (CH2), 55.9 (OCH3),
112.6 (CH), 115.1 (CH), 116.3 (CH), 116.5 (CH), 116.8
(CH), 126.4 (CH), 128.7 (CH), 128.7 (C), 128.9 (CH),
140.1 (C), 147.9 (C), 153.6 (C). HR MS: 214.10013
(C14H14O2þ; calcd 214.09938).
4.2.8. 4-tert-Butylphenylsulfamate 10. Prepared from 4-
tert-butylphenol (3.00 g) according to the general
method and purified by flash chromatography on silica
gel (pentane/EtOAc, 3:1) and was obtained as colorless
solid (4.24 g, 92%), mp 108 °C; TLC Rf ¼ 0:60. IR
2-Benzyl-4-methoxyphenyl sulfamate 5d. Prepared from
2-benzyl-4-methoxyphenol 4d (4.28 g) according to the
general method and purified by flash chromatography
on silica gel (pentane/EtOAc, 2:1), was obtained as a
pale yellow solid (3.86 g, 66%), mp 67 °C; TLC
Rf ¼ 0:55. IR (neat): 3390, 3277, 2932, 1736, 1594, 1489,
1349, 1164, 1932, 922, 844, 707 cmꢀ1. 1H NMR (CDCl3,
300 MHz): 3.74 (s, 3H), 4.11 (s, 2H), 5.23 (br, 2H), 6.76
(m, 2H), 7.28–7.40 (m, 6H). 13C NMR (CDCl3,
75 MHz): 36.4 (CH2), 55.6 (OCH3), 112.4 (CH), 116.9
(CH), 122.9 (CH), 126.6 (CH), 128.7 (CH), 129.3 (CH),
135.7 (C), 139.8 (C), 142.3 (C), 158.1 (C). HR MS:
293.06938 (C14H15NO4Sþ; calcd 293.07218).
(neat): 2972, 1740, 1360, 1229, 1215 cmꢀ1 1H NMR
.
(CDCl3, 300 MHz): 1.34 (s, 9H), 5.21 (br, 2H), 7.27 (d,
2H, J ¼ 8:8 Hz), 7.44 (d, 2H, J ¼ 8:8 Hz). 13C NMR
(CDCl3, 75 MHz): 31.4 (CH3), 34.3 (C), 121.5 (CH),
126.8 (CH), 147.7 (C), 150.5 (C). HR MS: 229.07872
(C10H15NO3Sþ; calcd 229.07727).
4.3. General procedure for the intramolecular amidation
and aziridination catalyzed by dirhodium(II) complexes
4.2.5. 2-Allylphenylsulfamate 7a. Prepared from 2-allyl-
phenol25 (1.81 g, 13.5 mmol) according to the general
method (chlorosulfonyl isocyanate (2.4 mL, 27 mmol,
2.0 equiv) and formic acid (1.0 mL, 27 mmol, 2.0 equiv))
and purified by flash chromatography on silica gel
(pentane/EtOAc, 3:1) and was obtained as a beige solid
(2.24 g, 78%), mp 64 °C; TLC Rf ¼ 0:50. IR (neat): 3013,
Dichloromethane (3.0–5.0 mL) was added through syr-
inge into a flask containing sulfamate ester (0.3–
0.5 mmol), PhI(OAc)2 (1.5 equiv), MgO (2.5 equiv),
ꢀ
activated 4 A molecular sieves, and rhodium catalyst
(0.5–5 mol %) under an argon atmosphere. The resulting
suspension was stirred vigorously at reflux until com-
plete consumption of starting material was indicated by

1024
C. Fruit, P. M€uller / Tetrahedron: Asymmetry 15 (2004) 1019–1026
thin layer chromatography. The mixture was diluted
with dichloromethane (5.0 mL) and filtered through a
pad of Celite. The filter cake was washed with dichloro-
methane and the filtrate concentrated under reduced
pressure. The residue was purified by chromatography
on silica gel using pentane/ethyl acetate as eluant to
afford the desired cyclic compound.
1H, J ¼ 8:5 Hz), 6.33 (d, 1H), 6.89 (dd, 1H), 7.05 (d, 1H,
J ¼ 8:9 Hz), 7.38 (m, 2H), 7.46 (m, 3H). 13C NMR
(CDCl3, 75 MHz): 55.7 (OCH3), 62.1 (CH), 113.3 (CH),
115.2 (C), 119.8 (CH), 122.8 (CH), 128.8 (CH), 129.5
(CH), 129.6 (CH), 137.8 (C), 145.4 (C), 156.5 (C). HR
MS: 291.05707 (C14H13NO4Sþ; calcd 291.05653).
4.3.5. 1a,2-Dihydro-1H-7-oxa-8-thia-8a-aza-benzo[a]cy-
clopropa[d]cycloheptene-8,8-dioxide 8a. Flash chromato-
graphy on silica gel (pentane/EtOAc, 3:1) afforded an
orange oil, which was recrystallized from hexane to give
a white solid (62%), mp 84 °C; TLC Rf ¼ 0:24. IR (neat):
3536, 3288, 2932, 1731, 1368, 1182, 1153, 1096, 868,
4.3.1. 4-Methyl-3,4-dihydro-benzo[e][1,2,3]oxathiazane-
2,2-dioxyde 6a.
Flash chromatography on silica gel
(pentane/EtOAc, 2:1) afforded a yellow oil (61%). TLC
Rf ¼ 0:60. IR (neat): 3266, 2987, 1738, 1484, 1423, 1364,
1201, 1167, 1115, 864, 798, 753 cmꢀ1. 1H NMR (CDCl3,
300 MHz): 1.74 (d, 3H, J ¼ 6:8 Hz), 4.76 (d, 1H,
J ¼ 9:2 Hz), 4.87–4.97 (m, 1H, J ¼ 6:8 Hz, J ¼ 9:2 Hz),
7.00 (d, 1H, J ¼ 8:1 Hz), 7.24 (m, 2H), 7.32 (m, 1H). 13C
NMR (CDCl3, 75 MHz): 20.1 (CH3), 53.0 (CH), 118.7
(CH), 123.6 (C), 125.4 (CH), 126.3 (CH), 129.5 (CH),
151.0 (C). HR MS: 199.03249 (C8H9NO3Sþ; calcd
199.03032). Enantiomer separation: GC (c-dex, 170 °C):
s1 ¼ 51:2 min, s2 ¼ 55:2 min.
779 cmꢀ1 1H NMR (CDCl3, 300 MHz): 2.46 (d, 1H,
.
J ¼ 4:3 Hz), 2.64 (d, 1H, J ¼ 4:3 Hz), 3.31–3.41 (m, 2H),
3.95 (dd, 1H, J ¼ 13 Hz), 7.24–7.38 (m, 4H). 13C NMR
(CDCl3, 75 MHz): 30.6 (CH2), 35.1 (NCH2), 44.2 (CH),
122.4 (CH), 126.9 (C), 127.9 (CH), 129.8 (CH), 131.0
(CH), 148.5 (C). MS: 211 (10), 130 (25), 118 (100), 91
(86), 78 (23), 65 (19), 51 (25). HR MS: 211.02989
(C9H9NO3Sþ; calcd 211.03032). Enantiomer separation:
HPLC (OD-H, hexane/i-PrOH 90/10, 0.5 mL minꢀ1): s1
¼ 28.7 min, s2 ¼ 32:4 min.
4.3.2. 4-Phenyl-3,4-dihydro-benzo[e][1,2,3]oxathiazane-
2,2-dioxyde 6b.
Flash chromatography on silica gel
(pentane/EtOAc, 3:1) afforded a yellow solid (77%), mp
132 °C. TLC Rf ¼ 0:70. IR (neat): 3285, 2924, 2352,
1737, 1480, 1449, 1402, 1361, 1194, 1162, 1098, 1021,
4.3.6.
4-Fluoro-1a,2-dihydro-1H-7-oxa-8-thia-8a-aza-
benzo[a]cyclopropa[d]cycloheptene-8,8-dioxide 8b. Flash
chromatography on silica gel (pentane/EtOAc, 3:1),
afforded 8b as a pale yellow solid (60%), mp 93 °C; TLC
Rf ¼ 0:23. IR (neat): 3283, 2964, 1728, 1486, 1368, 1260,
1
885, 839, 763, 753 cmꢀ1. H NMR (CDCl3, 300 MHz):
4.93 (d, 1H, J ¼ 8:6 Hz), 5.93 (d, 1H, J ¼ 8:6 Hz), 6.86
(d, 1H, J ¼ 8:1 Hz), 7.07–7.15 (m, 2H), 7.38 (m, 3H),
7.47 (m, 3H). 13C NMR (CDCl3, 75 MHz): 62.0 (CH),
118.8 (CH), 122.1 (C), 125.3 (CH), 128.6 (CH), 128.9
(CH), 129.5 (CH), 129.6 (CH), 129.7 (CH), 137.9 (C),
151.5 (C). HR MS: 261.04541 (C13H11NO3Sþ; calcd
261.04597). Enantiomer separation: HPLC (OD-H,
1153, 830, 771 cmꢀ1. H NMR (CDCl3, 300 MHz): 2.49
1
(d, 1H, J ¼ 4:5 Hz), 2.67 (d, 1H, J ¼ 4:5 Hz,), 3.28–3.35
(dd, 1H, J ¼ 5:3 Hz, J ¼ 15 Hz), 3.40 (m, 1H), 3.89–3.95
(dd, 1H, J ¼ 2:8 Hz, J ¼ 15 Hz), 6.95 (dd, 1H,
J ¼ 2:8 Hz, J ¼ 8:1 Hz), 7.03–7.10 (td, 1H), 7.23–7.30
(dd, 1H). 13C NMR (CDCl3, 75 MHz): 30.5 (CH2), 35.1
(NCH2), 44.0 (CH), 116.5 (CH), 117.6 (CH), 124.1
(CH), 129.1 (C), 144.5 (C), 162.7 (C–F). 19F NMR
(CDCl3, 282 MHz): )113.2 (CFCl3). MS (EI): 229 (19),
149 (46), 136 (100), 109 (71), 96 (21), 84 (48), 70 (13), 49
(77). HR MS: 229.02007 (C9H8FNO3Sþ; calcd
229.02089). Enantiomer separation: HPLC (OD-H,
hexane/i-PrOH 90/10, 0.5 mL minꢀ1): s1 ¼ 33:2 min,
s2 ¼ 38:6 min.
23 °C,
hexane/i-PrOH
s1 ¼ 29:5 min, s2 ¼ 46:3 min.
90/10,
0.5 mL minꢀ1),
4.3.3. 6-Chloro-4-phenyl-3,4-dihydro-benzo[e][1,2,3]oxa-
thiazane-2,2-dioxyde 6c. Flash chromatography on sil-
ica gel (pentane/EtOAc, 4:1) afforded a beige solid
1
(90%), mp 159 °C. TLC Rf ¼ 0:38. H NMR (CDCl3,
300 MHz): 5.11 (d, 1H, J ¼ 8:6 Hz), 5.87 (d, 1H,
J ¼ 8:6 Hz), 6.83 (d, 1H, J ¼ 8:1 Hz), 7.03 (d, 1H,
J ¼ 8:9 Hz), 7.30–7.39 (m, 3H), 7.49 (m, 3H). 13C NMR
(CDCl3, 75 MHz): 61.8 (CH), 120.3 (CH), 123.8 (C),
128.3 (CH), 128.8 (CH), 129.6 (CH), 129.9 (CH), 130.5
(C), 137.0 (C), 150.0 (C). MS: 295 (46), 215 (100), 181
(13), 152 (15), 104 (16), 77 (33), 51 (24). HR MS:
295.00507 (C13H10ClNO3Sþ; calcd 295.00699). Enan-
tiomer separation: HPLC (AD-H, 23 °C, hexane/i-PrOH
90/10, 0.2 mL minꢀ1): s1 ¼ 62:6 min, s2 ¼ 72:8 min.
4.3.7. 4-Methoxy-1a,2-Dihydro-1H-7-oxa-8-thia-8a-aza-
benzo[a]cyclopropa [d]cyclo-heptene-8,8-dioxide 8c. Flash
chromatography on silica gel (pentane/EtOAc, 3:1),
afforded 8c (58%) as a pale yellow solid, mp 119 °C;
TLC Rf ¼ 0:20. IR (neat): 3013, 2921, 1739, 1596, 1491,
1360, 1161, 1024, 836, 779 cmꢀ1 1H NMR (CDCl3,
.
300 MHz): 2.44 (d, 1H, J ¼ 4:5 Hz), 2.61 (d, 1H,
J ¼ 4:5 Hz), 3.21–3.28 (dd, 1H, J ¼ 4:9 Hz, J ¼
15:5 Hz), 3.40 (m, 1H), 3.83 (s, 3H), 3.90–3.96 (dd, 1H,
J ¼ 3:0 Hz, J ¼ 15:5 Hz), 6.72 (dd, 1H, J ¼ 3:0 Hz,
J ¼ 8:1 Hz), 6.85 (dd, 1H, J ¼ 3:0 Hz, J ¼ 8:9 Hz), 7.19
(d, 1H, J ¼ 8:9 Hz). 13C NMR (CDCl3, 75 MHz): 30.5
(CH2), 34.8 (NCH2), 44.6 (CH), 55.7 (OCH3), 114.0
(CH), 116.2 (CH), 123.3 (CH), 128.2 (C), 141.9 (C),
158.7 (C). MS: 241 (57), 206 (5), 161 (63), 148 (100), 133
(61), 121 (34), 105 (19), 91 (49), 77 (44). HR MS:
4.3.4. 6-Methoxy-4-phenyl-3,4-dihydro-benzo[e][1,2,3]oxa-
thiazane-2,2-dioxyde 6d. Flash chromatography on silica
gel (pentane/EtOAc, 4:1) afforded an orange oil (24%).
TLC Rf ¼ 0:25. IR (neat): 3283, 2927, 1739, 1491, 1427,
1365, 1196, 1166, 1029, 844 cmꢀ1 1H NMR (CDCl3,
.
300 MHz): 3.68 (s, 3H), 4.77 (d, 1H, J ¼ 8:5 Hz), 5.89 (d,

C. Fruit, P. M€uller / Tetrahedron: Asymmetry 15 (2004) 1019–1026
1025
241.03969 (C10H11NO4Sþ; calcd 241.04088). Enantio-
mer separation: HPLC (OD-H, hexane/i-PrOH: 90/10,
0.5 mL minꢀ1). s1 ¼ 46:1 min, s2 ¼ 50:4 min.
Dev. 2002, 5, 906; (d) Jacobsen, E. N. In Comprehensive
Asymmetric Catalysis; Jacobsen, E. N., Pfaltz, A.,
Zamamoto, H., Eds.; Springer: Berlin, 1999; Vol. 2, pp
€
607–618; (e) Muller, P. In Advances in Catalytic Processes;
Doyle, M. P., Ed.; JAI: Greenwich, CT, 1997; Vol. 2, pp
113–151.
3. (a) Abramovitch, R. A.; Bailey, T. D.; Takaya, T.; Uma,
V. J. Org. Chem. 1974, 39, 340–345; (b) Yamada, Y.;
Yamamoto, T.; Okawara, M. Chem. Lett. 1975, 361–362.
4.4. Intermolecular amidation of indane 9. Indan-1-yl-
sulfamic acid 4-tert-butyl-phenyl ester (11). General
procedure
€
4. (a) Sodergren, M. J.; Alonso, D. A.; Bedekar, A. V.;
Dichloromethane (5.0 mL) was added through syringe
into a flask containing sulfamate ester 10 (0.229 g,
1 mmol, 2 equiv), freshly distilled indane 9 (0.06 mL,
0.5 mmol), PhI(OAc)2 (0.482 g, 1.5 mmol, 3 equiv), MgO
Andersson, Pher. G. Tetrahedron Lett. 1997, 38, 6897–
6900; (b) Dauban, P.; Dodd, R. H. J. Org. Chem. 1999, 64,
5304–5307; (c) Chenna, P. H. Di.; Dauban, P.; Ghini, A.;
Baggio, R.; Garland, M. T.; Burton, G.; Dodd, R. H.
Tetrahedron 2003, 59, 1009–1014.
ꢀ
(0.100 g, 2.5 mmol, 5 equiv), activated 4 A molecular
€
5. (a) Muller, P.; Baud, C.; Jacquier, Y.; Moran, M.; Nageli,
I. J. Phys. Org. Chem. 1996, 9, 341–347; (b) Nageli, I.;
sieves, and rhodium catalyst (5 mol %) under argon
atmosphere at room temperature. The resulting sus-
pension was stirred vigorously at reflux until complete
consumption of starting material was indicated by thin
layer chromatography. The mixture was diluted with
dichloromethane (5 mL) and filtered through a pad of
Celite. The filter cake was washed with dichloromethane
and the filtrate concentrated under reduced pressure.
The residue was purified by chromatography on silica
gel using pentane/AcOEt 6:1 as eluent to afford the
sulfamidate 11 as a yellow solid, mp 84 °C; TLC
Rf ¼ 0:70. IR (neat): 3250, 2959, 1715, 1502, 1354, 1204,
Baud, C.; Bernardelli, G.; Jacquier, Y.; Moran, M.;
€
Muller, P. Helv. Chim. Acta 1997, 80, 1087–1105; (c)
€
Muller, P.; Baud, C.; Nageli, I. J. Phys. Org. Chem. 1998,
11, 597–601; (d) Nageli, I. Ph.D. thesis, University of
Geneva, 1998, Thesis No. 3018.
€
6. (a) Muller, P.; Baud, C.; Jacquier, Y. Tetrahedron 1996,
52, 1543–1548; (b) Muller, P.; Baud, C.; Jacquier, Y. Can.
€
J. Chem. 1998, 76, 738–750; (c) Baud, C. Ph.D. thesis,
University of Geneva, 1997, Thesis No. 2939.
7. (a) Liang, J.-L.; Yuan, S.-X.; Chan, P. W. H.; Che, C.-M.
Org. Lett. 2002, 4, 4507–4510; (b) Yamawaki, M.; Tsutsui,
H.; Kitagaki, S.; Anada, M.; Hashimoto, S. Tetrahedron
Lett. 2002, 43, 9561–9564; (c) Liang, J.-L.; Yuan, S.-X.;
Chan, P. W. H.; Che, C.-M. Tetrahedron Lett. 2003, 44,
5917–5920.
1182, 1150, 1061, 862, 846, 760, 750 cmꢀ1 1H NMR
.
(CDCl3, 300 MHz): 1.38 (s, 9H, CH3), 2.01–2.13 (m,
1H), 2.61–2.72 (m, 1H), 2.84–2.94 (m, 1H), 3.00–3.10
(m, 1H), 4.96 (d, 1H, J ¼ 8:3 Hz, NH), 5.12 (m, 1H),
7.29 (m, 6H), 7.45 (m, 2H). 13C NMR (CDCl3, 75 MHz):
30.0 (CH2), 31.4 (CH3), 34.4 (CH2), 34.6 (C), 60.1 (CH),
121.3 (CH), 124.5 (CH), 125.0 (CH), 126.7 (CH), 127.0
(CH), 128.7 (CH), 141.3 (C), 143.2 (C), 148.0 (C), 150.0
(C). MS: 345 (12), 150 (85), 135 (89), 117 (100), 91 (25),
77 (13); HR MS: 344.14221 (C19H23NO3Sþ; calcd
344.13987). Enantiomer separation: HPLC (OD-H,
hexane/i-PrOH 90/10, 0.5 mL minꢀ1): s1 ¼ 13:9 min,
s2 ¼ 15:7 min.
8. Duran, F.; Leman, L.; Ghini, A.; Burton, G.; Dauban, P.;
Dodd, R. H. Org. Lett. 2002, 4, 2481–2483.
9. For Rh-catalyzed intramolecular amidation using sulfa-
mates, see: (a) Espino, C. G.; When, P. M.; Chow, J.; Du
Bois, J. J. Am. Chem. Soc. 2001, 123, 6935–6936; For
amidation with carbamates, see: (b) Espino, C. G.; Du
Bois, J. Angew. Chem., Int. Ed. 2001, 40, 598–600; (c)
Padwa, A.; Stengel, T. Org. Lett. 2002, 4, 2137–2139; (d)
Levites-Agababa, E.; Menhaji, E.; Perlson, L. N.; Rojas,
C. M. Org. Lett. 2002, 4, 863–865.
10. During preparation of this manuscript Du Bois reported
intramolecular amination reactions of chiral sulfamates
catalyzed by dirhodium(II): When, P. M.; Lee, J.; Du Bois,
J. Org. Lett. 2003, 5, 4823–4826.
ꢁ
11. Melendez, R. E.; Lubell, W. D. Tetrahedron 2003, 59,
2581–2616.
Acknowledgements
12. Nicolaou, K. C.; Huang, X.; Snyder, S. A.; Rao, P. B.;
Bella, M.; Reddy, M. V. Angew. Chem., Int. Ed. 2002, 41,
834–838.
13. Williams, A. J.; Chakthong, S.; Gray, D.; Lawrence,
R. M.; Gallagher, T. Org. Lett. 2003, 5, 811–814.
14. Atfani, M.; Wei, L.; Lubell, W. D. Org. Lett. 2001, 3,
2965–2968.
15. Aguilera, B.; Fernandez-Mayoralas, A. Chem. Commun.
1996, 127–128.
16. Cohen, S. B.; Halcomb, R. L. J. Am. Chem. Soc. 2002,
124, 2534–2543.
This work was supported by the Swiss National Science
Foundation (Projects No. 20-52581.97 and 2027-
048156) and by the European Commission for Science,
Research and Development (COST Action D12). The
authors are indebted to L. Nicolas for carrying out parts
of the experiments, A. Pinto and J.-P. Saulnier for the
NMR spectra, and D. Klink and E. Sandmeier for the
mass spectra.
17. Fleming, J. J.; Fiori, K. W.; Du Bois, J. J. Am. Chem. Soc.
2003, 125, 2028–2029.
18. Liang, J.-L.; Yuan, S.-X.; Huang, J.-S.; Yu, W.-Y.; Che,
C.-M. Angew. Chem., Int. Ed. 2002, 41, 3465–3468.
19. Okada, M.; Iwashita, S.; Koizumi, N. Tetrahedron Lett.
2000, 41, 7047–7051.
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2. (a) Dauban, P.; Dodd, R. H. Synlett 2003, 1571–1586; (b)
20. Mu€ller, P.; Allenbach, Y.; Robert, E. Tetrahedron: Asym-
metry 2003, 14, 779–785.
€
Muller, P.; Fruit, C. Chem. Rev. 2003, 103, 2905–2919; (c)
Watson, I. D. G.; Yudin, A. K. Curr. Opin. Drug Discov.
21. Allenbach, Y. Ph.D. thesis, University of Geneva,
2003.

1026
C. Fruit, P. M€uller / Tetrahedron: Asymmetry 15 (2004) 1019–1026
22. For intermolecular aziridination using aliphatic sulfamate,
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25. Wang, E.-C.; Hsu, M.-K.; Lin, Y.-L.; Huang, K.-S.
Heterocycles 2002, 57, 1997–2010.
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