Investigations in the transition metal catalyzed aziridination of olefins, amination, and other insertion reactions with Bromamine-T as the source of nitrene

Article abstract of DOI:10.1021/jo000013v

Investigations into the transition metal catalyzed aziridination of olefins with Bromamine-T as a new source of nitrene is presented in this account. Comparison of Chloramine-T and Bromamine-T in this reaction indicates that the latter is superior as the source of nitrene. Systematic study with several transition metal based catalysts suggests that Cu-halides are the best catalysts. A first report of aziridination under microwave and ultrasound irradiation conditions is also presented. Copper-catalyzed aziridination of methyl cinnamate with Bromamine-T did not proceed at ambient temperature but was effected smoothly under ultrasound irradiation to furnish trans-aziridine selectively, while under microwave irradiation, a mixture of cis and trans isomers, was obtained. It has been demonstrated that aziridination of olefins proceeds smoothly with inexpensive bleaching powder. Preliminary results of Rh-catalyzed benzylic insertion reactions with Bromamine-T are included in this account.

Full text of DOI:10.1021/jo000013v

30
J . Org. Chem. 2001, 66, 30-34
In vestiga tion s in th e Tr a n sition Meta l Ca ta lyzed Azir id in a tion of
Olefin s, Am in a tion , a n d Oth er In ser tion Rea ction s w ith
Br om a m in e-T a s th e Sou r ce of Nitr en e†
Bhanu M. Chanda,* Renu Vyas, and Ashutosh V. Bedekar*
Division of Organic Chemistry: Technology, National Chemical Laboratory, Pune - 411 008, India
bhanu@dalton.ncl.res.in
Received J anuary 6, 2000
Investigations into the transition metal catalyzed aziridination of olefins with Bromamine-T as a
new source of nitrene is presented in this account. Comparison of Chloramine-T and Bromamine-T
in this reaction indicates that the latter is superior as the source of nitrene. Systematic study with
several transition metal based catalysts suggests that Cu-halides are the best catalysts. A first
report of aziridination under microwave and ultrasound irradiation conditions is also presented.
Copper-catalyzed aziridination of methyl cinnamate with Bromamine-T did not proceed at ambient
temperature but was effected smoothly under ultrasound irradiation to furnish trans-aziridine
selectively, while under microwave irradiation, a mixture of cis and trans isomers. was obtained.
It has been demonstrated that aziridination of olefins proceeds smoothly with inexpensive bleaching
powder. Preliminary results of Rh-catalyzed benzylic insertion reactions with Bromamine-T are
included in this account.
In tr od u ction
olefins to form aziridines; however, their utility is limited
due to poor conversions and formation of side products.5
The metal-catalyzed reaction of in situ generated
nitrenes with olefins is an efficient method for the
practical preparation of aziridines and has received much
attention in recent years. The first metal-catalyzed
nitrogen atom transfer process was reported by Kwart
and Khan6 who demonstrated the decomposition of
benzenesulfonyl azide when heated in copper dust in the
presence of cyclohexene resulting in the formation of the
corresponding aziridine (Scheme 1).
Aziridines, belonging to the group of the smallest of
heterocycles, are an important class of compounds in
organic chemistry.1 Significance of this nitrogen-contain-
ing heterocycle is due to its presence as a subunit in
several natural products,1b as efficient chiral auxiliaries1b
and as ligands in metal-catalyzed asymmetric transfor-
mations.2 Owing to their varied applications, synthesis
of aziridines is a subject of considerable research over
several years.
A single atom transfer to olefins is the shortest route
to three-membered cyclic compounds. This mode is
extensively explored for the preparation of cyclopropanes3a
and epoxides3b from olefins. Catalytic addition of a
carbene moiety to imine results in the formation of
aziridine, but the yields are often on lower side.4 Simi-
larly, the transfer of a nitrogen atom onto an olefin offers
an attractive synthesis of aziridine. Thermally or pho-
tochemically generated nitrenes are known to react with
A popular approach to prepare aziridines is via the
reaction of nitrene generated from [N-(arenesulfonyl)-
imino]phenyliodinanes7,8 (PhIdNSO2Ar) with olefins.
Several transition metal based catalysts are employed
for the acceleration of this reaction via the intermediate
metal nitrenoid species. In another approach aziridine-
2-carboxylates are prepared by reaction of (ethoxycarbo-
nyl)nitrene generated from ethyl N-[(4-nitrobenzenesulfo-
nyl)oxy]carbamate (NsONHCO2Et).9 Recently, Chlora-
mine-T (TsNNaCl) has been introduced10a as a source of
nitrogen in the copper(I)-catalyzed aziridination of ole-
fins.
* To whom correspondence should be addressed. Fax: +91 020
5893614.
† This paper is dedicated to Dr. T. Ravindranathan on the occasion
of his 60th birthday.
(1) (a) Padwa, A.; Woolhouse, A. D. Comprehensive Hetrocyclic
Chemistry; Lwowski, W., Ed.; Pergamon: Oxford, 1983; Vol. 7, pp 47-
93. (b) Tanner, D. Angew. Chem., Int. Ed. Engl. 1994, 33, 599. (c) Kemp,
J . E. G. Comprehensive Organic Synthesis; Trost, B. M., Fleming, I.,
Eds.; Pergamon: Oxford, 1991; Vol. 7, p 469.
(2) (a) Tanner, D.; Andersson, P. G.; Harden, A.; Somfai, P.
Tetrahedron Lett. 1994, 35, 4631. (b) Andersson, P. G.; Guijarro, D.;
Tanner, D. Synlett 1996, 727. (c) Tanner, D.; Korno, H. T.; Guijarro,
D.; Andersson, P. G. Tetrahedron 1998, 54, 14213.
(3) (a) For a review on metal-catalyzed cyclopropanation reaction,
see: Doyle, M. P. Chem. Rev. 1986, 86, 919. (b) Doyle, M. P. in Catalytic
Asymmetric Syntheis; Ojima, I., Ed.; VCH: New York, 1993; Chapter
3. (c) For epoxidation, see: J orgensen, K. A. Chem. Rev. 1989, 89, 431.
(4) (a) Hansen, K. B.; Finney, N. S.; J acobsen, E. N. Angew. Chem.,
Int. Ed. Engl. 1995, 34, 676. (b) Rasmussen, K. G.; J orgensen, K. A.
J . Chem. Soc., Chem. Commun. 1995, 1401. (c) Moran, M.; Bernar-
dinelli, G.; Mu¨ller, P. Helv. Chim. Acta 1995, 78, 2048. (d) Madan
Mohan, J .; Uphade, B. S.; Choudhary, V. R.; Ravindranathan, T.;
Sudalai, A. J . Chem., Chem. Commun. 1997, 1429.
(5) (a) Lwowski, W. Nitrenes, Lwowski, W. Ed.; Interscience: New
York, 1970; pp 185-247. (b) Lwowski, W. Azides and Nitrenes,
Reactivity and Utility; Scriven, E. F. V., Ed.; Academic: New York,
1984; pp 205-246.
(6) Kwart, H.; Kahn, A. A. J . Am. Chem. Soc. 1967, 89, 1951.
(7) (a) Mansuy, D.; Mahy, J . P.; Dureault, A.; Bedi, G.; Battioni, P.
J . Chem. Soc., Chem. Commun. 1984, 1161. (b) Mahy, J . P.; Bedi, G.;
Battioni, P.; Mansuy, D. Tetrahedron Lett. 1988, 29, 1927. (c) Evans,
D. A.; Faul, M. M.; Bilodeau, M. T. J . Am. Chem. Soc. 1994, 116, 2742.
(d) Pe´rez, P. J .; Brookhart, M.; Templeton, J . L. Organometallics 1993,
12, 261. (e) Knight, J . G.; Muldowney, M. P. Synlett 1995, 949.
(8) (a) Mu¨ller, P.; Baud, C.; J acquier, Y. Tetrahedron 1996, 52, 1543.
(b) Na¨geli, I.; Baud, C.; Bernardinelli, G.; J acquier, Y.; Moran, M.;
Mu¨ller, P. Helv. Chim. Acta 1997, 80, 1087. (c) So¨dergren, M. J .; Alonso,
D.; Bedekar, A. V.; Andersson, P. G. Tetrahedron Lett. 1997, 38, 6897.
(d) Macikenas, D.; Meprathu, B. V. Protasiewicz, J . D. Tetrahedron
Lett. 1998, 39, 191.
(9) Carducci, M.; Fioravanti, S.; Loreto, M. A.; Pellacani, L.; Tardella,
P. A. Tetrahedron Lett. 1996, 37, 3777.
10.1021/jo000013v CCC: $20.00 © 2001 American Chemical Society
Published on Web 12/13/2000

Aziridination of Olefins
J . Org. Chem., Vol. 66, No. 1, 2001 31
Ta ble 1. Micr ow a ve-Assisted Azir id in a tion of Styr en e
w ith Br om a m in e-T Usin g Differ en t Ca ta lysts
Sch em e 1
entry
metal halidea
% yieldb
1
2
3
4
5
6
7
8
9
CuCl2
NiCl2
CoCl2
FeCl3
MgCl2
MnCl2
SrCl2
CuBr2
70
60
56
63
57
54
40
88
30
c
Rh2(OAc)4
10
no catalyst
no reaction
a
A mixture of the catalyst (5 mol %), Bromamine-T (1 equiv),
and styrene (5 equiv) in acetonitrile was exposed under microwave
b
for 12 min. Isolated yield. c CAUTION! Sparks were observed
occasionally.
higher yield compared to that with 1 as the nitrogen
source. Improvement in the efficiency of aziridination
with 2 was more evident in the case of cyclooctene where
the yield was almost doubled as compared to that with
1. Aziridination of cyclooctene performed with 2 in the
presence of Cu(II)Cl2 as the catalyst proceeds with almost
the same efficiency. This is probably because Bro-
mamine-T 2 oxidizes cuprous chloride to cupric chloride.
The actual catalytic species could be Cu(II) observed by
Evans7b in the aziridination of olefins with PhINTs.
Microwave-assisted chemical transformations have
gained importance in recent years as they expedite the
reactions with more efficiency. With an aim to reduce the
reaction time and also to achieve aziridination with
relatively less reactive olefins, this reaction was inves-
tigated under the microwave irradiation. Standard reac-
tion of styrene with 2 catalyzed by CuCl clearly indicates
marked improvement of this reaction. To the best of our
knowledge, this is the first report of microwave-assisted
catalytic aziridination of olefins.
F igu r e 1.
In our preliminary communication we11 have demon-
strated for the first time the use of Bromamine-T (TsN-
NaBr) as a superior source of nitrogen in the copper(I)-
or copper(II)-catalyzed aziridination of olefins. In this
account we present details of this reaction and further
applications with this versatile reagent.
Resu lt a n d Discu ssion
Although Chloramine-T, 1 (N-chloro-N-sodio-p-tolu-
enesulfonamide), has found several synthetic uses,10b its
bromo analogue, Bromamine-T, 2, has been mainly
utilized as a titrant in oxidimetric estimations12 and
occasionally as an oxidant.13 Komatsu and co-workers
have recently reported10a copper-catalyzed aziridination
of olefins with Chloramine-T, 1, as the source of nitrogen.
A range of olefins was subjected to this reaction, and
aziridines were isolated in low to moderate yields.
Aziridination with some substrates was not so effective
with Chloramine-T. For example cyclohexene gave un-
wanted products probably of allylic amination,6,7b,c and
1-decene furnished the corresponding aziridine in only
12% yield. In view of these limitations these reactions
were reinvestigated11 with Bromamine-T, 2, as the source
of nitrogen. During this period, three more accounts were
published dealing with aziridination of olefins with
Chloramine-T mediated by iodine,10b copper catalyst,14
and one from Sharpless15a using phenyltrimethylammo-
nium tribromide (PTAB) as the activator. Recently
Sudalai15b reported the use of pyridinium hydrobromide
perbromide for similar conversion.
One of the objectives of the current work was also to
establish the most suitable metal catalyst for aziridina-
tion of olefins with 2 as the source of nitrogen. With this
in view, styrene was subjected to aziridination with 2 and
catalyzed by different metal salts under microwave
irradiation (Table 1).
It is evident from this study that the halides of copper
are ideal candidates as catalysts for this reaction. Having
established the superiority of copper halides as the
catalysts, the mechanistic aspects of this important
conversion were also investigated. By analogy with a
well-established mechanism of metal-catalyzed cyclopro-
panation of olefins, one possibility is the transfer of
nitrene generated from 1 or 2 in the presence of Cu
catalyst, via a Cu-nitrenoid intermediate. Experimental
evidence of this possibility was furnished by J acobsen et
al.17 in their work on the asymmetric aziridination with
PhINTs as a nitrene precursor. Reaction of Chloramine-T
with an olefin in the presence of a positive halogen results
in the formation of aziridine. Komatsu and co-workers10b
used iodine to initiate the reaction and suggest the
formation of a cyclic iodonium intermediate, followed by
nucleophilic addition of the nitrogen to give aziridine.
Sharpless15 performed this reaction with PTAB, a phase-
transfer agent, which supplies bromonium ion to catalyze
the reaction in more or less the same fashion. The Cu-
Preliminary experiments for comparison of Chloram-
ine-T, 1, and Bromamine-T, 2, in the aziridination were
carried out with Cu(I)Cl as the catalyst and with styrene
as the standard substrate. Under identical conditions, 2
furnished the corresponding aziridine in substantially
(10) (a) Ando, T.; Minakata, S.; Ryu, I.; Komatsu, M. Tetrahedron
Lett. 1998, 39, 309. (b) Ando, T.; Kano, D.; Minakata, S.; Ryu, I.;
Komatsu, M. Tetrahedron 1998, 54, 13485.
(11) Vyas, R.; Chanda, B. M.; Bedekar, A. V. Tetrahedron Lett. 1998,
39, 4715.
(12) Nair, C. G. R.; Lalithakumari, R.; Senan, P. I. Talanta 1978,
25, 525.
(13) Mahadevappa, D. S.; Ananda, S.; Murthy, A. S. A.; Rangappa,
K. S. Tetrahedron 1984, 40, 1673.
(14) Albone, D. P.; Aujla, P. S.; Taylor, P. C.; Challenger, S.; Derrick,
A. M. J . Org. Chem. 1998, 63, 9569.
(15) (a) J eong, J . U.; Tao, B.; Sagasser, I.; Henniges, H.; Sharpless,
K. B. J . Am. Chem. Soc. 1998, 120, 6844. (b) Iliyas Ali, S.; Nikalje, M.
D.; Sudalai, A. Org. Lett. 1999, 1, 705.
(16) Caddick, S. Tetrahedron 1995, 51, 10403 and references therein.
(17) Li, Z.; Quan, R. W.; J acobsen, E. N. J . Am. Chem. Soc. 1995,
117, 5889.

32 J . Org. Chem., Vol. 66, No. 1, 2001
Chanda et al.
Ta ble 2. Com p a r ison of 1 a n d 2 in th e Azir id in a tion of
Olefin s
Sch em e 2
Sch em e 3
catalyzed aziridination of olefins could follow an alterna-
tive Lewis acid mechanism. Support for this mechanism
is available in the literature18 in the form of examples of
epoxidation and aziridination with PhINTs catalyzed by
simple Lewis acids.
Recently, Taylor and co-workers14 have reported Cu-
catalyzed aziridination and amination of alkenes with
hydrated Chloramine-T. Aziridination of styrene with
commercial Chloramine-T trihydrate did not give epoxide
even in the absence of molecular sieves, suggesting a
possible Cu-nitrenoid mechanism. Similarly the reaction
of styrene with Bromamine-T trihydrate in the presence
of CuCl2 as the catalyst in acetonitrile without molecular
sieves was carried out. Although aziridine 3 was isolated,
no styrene oxide could be detected in the reaction mixture
(Scheme 2), lending support to the Cu-nitrenoid mecha-
nism.
Aziridination did not proceed in the absence of catalyst
both with 110b as well as with 2. Aziridination of cy-
clooctene with both CuCl and CuCl2 proceeded in good
yield, but with 1 equiv of NaBr and without Cu-catalyst
trans-1,2-dibromocyclooctane was obtained as the sole
product (Scheme 3). We believe Bromamine-T serves as
the source of bromonium ion in the absence of copper
halide.
a
Isolated yield. Aziridines are characterized by spectroscopic
methods. Taken from the literature.10a c All the reactions under
b
microwave were catalyzed by CuCl2 (5 mol %) for 12 min; in some
experiments longer irradiation resulted in the formation of dark
reaction mixtures. Present work with 1. e With CuCl2 (5 mol %).
d
f With CuBr2 (20 mol %) with formation of a mixture of cis and
trans isomers, detected by NMR.
Sch em e 4
These observations are in agreement with the mech-
anism suggested by J acobsen17 which involves a copper-
nitrenoid intermediate similar to generally accepted
analogous copper-carbenoid intermediate for the cyclo-
propanation mechanism.3b
specific chemical reactivity, although the detailed mech-
anism of the sonochemical excitation is still unclear.
Aziridination of styrene with CuCl2 as catalyst under
ultrasound irradiation in the presence of Bromamine-T
was found to give good yield in short time (Scheme 4).
Evaluation of aziridination under this improved condi-
tion was of particular interest. Thus, Cu-catalyzed aziri-
dination of methyl cinnamate with Bromamine-T as a
nitrogen source resulted in selective formation of trans-
aziridine as depicted in Scheme 5. This is in contrast to
the results of same reaction under microwave irradiation,
where a mixture of cis and trans isomers of aziridine was
obtained. Such results may be attributed to the difference
in the activation mechanisms of both the processes
(Scheme 5).
A variety of substrates were examined for aziridination
with Chloramine-T, 1, and with Bromamine-T, 2, in the
presence of copper catalyst. Improvement in the efficiency
with 2 compared to 1 in the case of styrene and cyclo-
hexene has already been mentioned. Similar pattern was
observed in a number of structurally diverse substrates
(Table 2). It was interesting to note that there was no
aziridination with less reactive cinnamates with 1 as well
as with 2 in the presence of CuCl2 and CuBr2. However,
reaction proceeded under microwave irradiation with
CuBr2 to yield the aziridine, albeit in poor yield. In
general, it was observed that microwave-mediated aziri-
dination of olefins with Bromamine-T was effective in a
very short reaction time.
Recently, three independent groups led by Komatsu,
Sharpless, and Sudalai have reported aziridination of
olefins catalyzed by iodine,10b phenyltrimethylammonium
tribromide (PTAB),15a and pyridinium hydrobromide
perbromide,15b respectively. All these reactions proceed
by an ionic mechanism. Application of a cheap and
Reactions characteristic of ultrasound irradiation have
been named sonochemical transformations and have
become topical in recent years.19 Sonication induces a
(18) Yang, Y.; Diederich, F.; Valentine, J . S. J . Am. Chem. Soc. 1991,
113, 7195.
(19) Lindley, J .; Mason, T. J . Chem. Soc. Rev. 1987, 16, 275.

Aziridination of Olefins
Sch em e 5
J . Org. Chem., Vol. 66, No. 1, 2001 33
Ta ble 4. Rh -Ca ta lyzed a Ben zylic Am in a tion w ith
Br om a m in e-T
Ta ble 3. Blea ch in g P ow d er In itia ted Azir id in a tion of
Olefin sa
a
Reactions were performed in ultrasound (20 min) with 2.5 mol
% Rh2(OAc)4 in acetonitrile. b Isolated yield. c Yield in parentheses
refers to the reaction at room temperature for 12 h.
albeit in poor yield. Subjecting the same reaction under
ultrasound conditions resulted in enhanced yields of the
desired product (Table 4). Under optimized conditions,
amination of ethyl benzene and indane also proceeded
smoothly to yield the desired products. These Rh-
catalyzed insertion reactions of Bromamine-T are similar
to the ones observed by Mu¨ller et al.8b though with a
different source of nitrene.
The successful ultrasound induced benzylic amination
with Bromamine-T in the presence of Rh2(OAc)4 has a
wide scope and has opened several possibilities for
further exploitation. This can be a practical approach
toward preparation of benzylic amines.
In conclusion, the superiority of Bromamine-T over
Chloramine-T in the aziridination of olefins has been
amply demonstrated. Application of microwave and ul-
trasound techniques has resulted in enhanced yields of
aziridines in shorter reaction times.
a
Reactions were carried out at room temperature in dry
acetonitrile with 20% calcium hypochlorite as catalyst. Yields are
of isolated product.
Exp er im en ta l Section
The H NMR spectra were recorded in CDCl3 with TMS as
commercially available reagent, i.e., calcium hypochlorite
[Ca(OCl)2] commonly known as bleaching powder to
initiate aziridination of olefins was explored in the
present work. Preliminary experiments with both Bro-
mamine-T and Chloramine-T as a nitrogen source gave
good yields of aziridines under mild reaction conditions
and simple workup procedures. The methodology is
convenient and obviates the need for a metal catalyst.
Several substrates were screened under similar condi-
tions, and it can be seen from Table 3 that the yields
obtained are comparable to those of previous reports
using different reagents.
Substitution of benzyl halides or alcohol derivatives by
an amine or its equivalent is a general method for the
preparation of benzylic amines.20 Recently, Sharpless15a
and Taylor14 have reported both allylic and benzylic
amination with Chloramine-T. In our continuing efforts
toward application of Bromamine-T in such reactions,
benzylic amination was studied, and the preliminary
results obtained are presented here.
1
internal standard on
a Bruker spectrometer (200 MHz).
Sonication experiments were carried out using an ultrasonic
bath (Sheishin model) operating at 36 kHz. The bulk temper-
ature during sonication was kept at 25 °C. Microwave irradia-
tions were carried out in a Batliboi Eddy domestic microwave
oven operating at 2450 MHz, and reactions were performed
at 30% of its full power. Column chromatography was per-
formed with Merck silica gel using a gradient method with a
mixture of light petroleum ether and ethyl acetate (5 to15%)
as eluent. Acetonitrile was distilled over CaH2 and stored over
molecular sieves.
Typ ica l P r oced u r e for Azir id in a tion a t Room Tem -
p er a tu r e. A two-necked 25 mL round-bottomed flask was
charged with Bromamine T (100 mg, 0.0004 mol), 5 Å
powdered molecular sieves (10 mg), and anhydrous CuCl2 (5
mg, 0.00004 mol). Anhydrous acetonitrile (5 mL) and styrene
(0.23 mL, 0.002 mol) were then added, and the suspension was
stirred for 12 h at room temperature under inert atmosphere.
It was diluted with dichloromethane and passed through a
short plug of silica gel. The crude reaction mixture was purified
by silica gel column chromatography to yield 45 mg (45%) of
the pure aziridine product.
Tetralin was subjected to benzylic amination with
Bromamine-T in the presence of catalytic amount of Rh2-
(OAc)4. The expected insertion product was obtained
R ep r esen t a t ive P r oced u r e of Azir id in a t ion Usin g
Blea ch in g P ow d er . A two-necked 25 mL round-bottomed
flask was charged with of Bromamine-T (100 mg, 0.0004 mol),
5 Å powdered molecular sieves (10 mg), and commercial
calcium hypochlorite (5 mg, 10 mol %). Anhydrous acetonitrile
(5 mL) was then added, and after 5 min, styrene (0.2 mL,
(20) (a) Gibson, M. S.; Bradshaw, R. W. Angew. Chem., Int. Ed. Engl.
1968, 7, 919. (b) Trost, B. M.; van Vranken, D. L. Chem. Rev. 1996,
96, 395.

34 J . Org. Chem., Vol. 66, No. 1, 2001
Chanda et al.
0.002mol) was added and the suspension was stirred at room
temperature for 12 h under inert atmosphere. The crude
reaction mixture was passed through a short pad of silica gel
and the solvent concentrated in a vacuum. The crude product
obtained was purified by chromatography on silica gel to yield
68 mg (68%) of the pure aziridine.
1H NMR δ 7.77 (d, J ) 8.3 Hz, 2H), 7.31-7.24 (m, 7H), 4.44
(d, J ) 3.9 Hz, 1H), 3.85 (s, 3H), 3.53 (d, J ) 4 Hz, 1H), 2.41
(s, 3H), 1.59-1.20 (m, 12H). MS m/z (%), 278 (2), 259 (M+, 3),
210 (12), 125 (100), 91 (45), 55 (58).
N-(p-Tolylsu lfon yl)-7-a za bicyclo[4.1.0]h ep ta n e (Table
1
2, entry 6):7c IR ν 3020, 1600, 1440, 1395, 965, 920 cm-1. H
Typ ica l P r oced u r e of Azir id in a tion Usin g Ultr a sou n d .
Styrene (0.2 mL, 0.002mol), Bromamine-T (100 mg, 0.0004
mol), and CuCl2 (5 mg, 10 mol %) in 5 mL of anhydrous
acetonitrile were taken in a glass tube which was then
irradiated in the sonication bath for 20 min under dry
atmosphere. The catalyst was filtered off, and the crude
reaction mixture was purified using silica gel column chro-
matography to yield 69 mg (64%) of the aziridine.
Typ ica l P r oced u r e of Azir id in a tion u n d er Micr ow a ve
Con d ition s. A 25 mL pear-shaped round flask was charged
with Bromamine-T (50 mg, 0.0002 mol), 5 Å powdered molec-
ular sieves (5 mg), and CuBr2 (5.0 mg, 10 mol %). Dry ace-
tonitrile (2 mL) and styrene (0.1 mL, 0.001mol) were then
added, and the reaction mixture was irradiated for 12 min in
domestic microwave oven. After cooling, the contents of the
flask were passed through a short plug of silica gel. The pure
product, 44 mg (88%) was obtained by column chromatogra-
phy.
Typ ica l P r oced u r e for Ben zylic Am in a t ion u n d er
Son ica tion . To a mixture of Rh2(OAc)4 (4.0 mg, 2.5 mol %),
molecular sieves (40 mg), and tetralin (0.19 mL, 0.001mol) in
dry acetonitrile (2 mL) was added Bromamine-T (100 mg,
0.0004 mol). The reaction mixture was subjected to ultrasound
radiation for 20 min. After filtration, the reaction mixture was
subjected to purification by column chromatography to give
77 mg of the product (70%)
NMR δ 7.81 (d, J ) 9.8 Hz, 2H), 7.40 (d, J ) 8.9 Hz, 2H), 3.10
(t, 3H), 2.49 (s, 3H), 1.81 (m, 4H), 1.5-1.4(m, 4H). MS, m/z
(%) 252 (M + 1, 1), 210 (2), 155 (6), 96 (100), 91 (40), 69 (40),
65 (17).
3-(4 Meth ylph en ylsu lfon yl)-3-azatr icyclo[3.2.1.0]octan e
1
(Table 2; entry 7):7c IR ν 3016, 1300, 1280, 1080,960 cm-1. H
NMR δ 7.97 (d, J ) 8 Hz, 2H), 6.77 (d, 2H), 2.87 (s, 2H), 1.98
(s, 3H), 1.86 (s, 4H), 1.45 (dt, J ) 2.0 Hz, 1H), 0.97 (m, 2H),
0.8 (m, 2H). MS m/z (%) 263 (M + 1, 1), 199 (18), 155 (30), 91
(100), 60 (35).
N-(p-Tolylsu lfon yl)-2-octyla zir id in e (Table 2; entry 8):
21
IR ν 3017, 1327, 1217, 1161, 916, 783, 769, 713, 696, 665
cm-1. H NMR δ 8.20 (d, J ) 10.8 Hz, 2H), 7.59 (m, 7H), 4.18
1
(dd, J ) 9.7 and 6.5 Hz, 1H), 3.39 (d, J ) 9.8 Hz, 1H), 2.82 (s,
3H), 2.72 (d, J ) 6.3 Hz, 1H). MS m/z (%) 273 (M+, 5), 155 (4),
118 (83), 91 (100), 65 (21).
N -(p -Tolylsu lfon yl)-2-ca r b om e t h oxy-3-p h e n yla zir i-
d in e (Table 2; entry 9):7c IR ν 3068, 3021, 2960, 1750, 1600,
1
1412, 1167, 906 cm-1. H NMR (trans isomer) δ 7.77 (d, J )
8.3 Hz, 2H), 7.31-7.24 (m, 7H), 4.44 (d, J ) 3.9 Hz, 1H), 3.85
(s, 3H), 3.53 (d, J ) 4.0 Hz, 1H), 2.41 (s, 3H). 1H NMR (cis
isomer) δ 7.90 (d, J ) 8 Hz, 1H), 7.40 (d, J ) 8 Hz, 1H), 7.25
(m, 7H), 4.10 (d, J ) 8.2 Hz, 1H), 3.70 (d, J ) 7.8 Hz, 1H),
3.50 (s, 3H), 2.49 (s, 3H). MS m/z (%) 332 (M + 1, 5), 331 (M+,
8), 300 (10), 176 (75), 144 (25), 116 (100), 91 (70), 65 (30).
N-(p -Tolylsu lfon yl)-2-ca r b o-(2-m et h yl-2-p r op oxy)-3-
p h en yla zir id in e (Table 2; entry 10):7c IR ν 3028, 1740, 1085,
Sp ectr a l Da ta of Selected Com p ou n d s.
N-(p-Tolylsu lfon yl)-2-p h en yla zir id in e (Tables 1 and 2;
910 cm-1 1H NMR δ 7.80 (d, J ) 8 Hz, 2H), 7.40-7.00 (m,
.
7H), 4.44 (d, J ) 2 Hz, 1H), 3.40 (d, J ) 2 Hz, 1H), 2.49 (s, 9
H), 1.5 (s, 9H). MS m/z (%), 373 (M+, 0. 5), 300 (18), 273 (18),
162 (70), 91(100).
entry 1):7c IR ν 3017, 1327, 1217, 1161, 916, 783, 769, 713,
1
696, 665 cm-1. H NMR δ 8.20 (d, J ) 10.8 Hz, 2H), 7.59 (m,
7H), 4.18 (dd, J ) 9.7, 6.5 Hz, 1H), 3.39 (d, J ) 9.8 Hz, 1H),
2.82 (s, 3H), 2.72 (d, J ) 6.3 Hz, 1H). MS m/z (%) 273 (M+, 5),
155 (4), 118 (83), 91 (100).
1-{N- (p-Tolylsu lfon yl)a m in o}-1,2,3,4- tetr a h yd r on a p h -
th a len -1-yl (Table 4; entry 1):14 IR ν 3361, 3236, 3000, 2847,
N-(p-Tolylsu lfon yl)-2-p h en yl-2-m eth yla zir id in e (Table
1
1140, 742 cm-1. H NMR δ 7.90 (d, J ) 8 Hz, 2H), 7.40 (d, J
1
2; entry 2):7c IR ν 3060, 3028, 2992, 1440, 930 cm-1. H NMR
) 8 Hz, 2H), 7.30-6.85 (m, 4H), 4.85 (d, J ) 6 Hz, 2H), 4.50
(m, 1H), 2.90-2.64 (m, 2H), 2.45 (s, 3H), 1.90-1.68 (m, 4H).
Mass m/z (%), 301 (M+, 2), 235 (20), 155 (40), 146 (90), 130
(100), 91 (80).
δ 7.80 (d, J ) 8 Hz, 2H), 7.55-7.15 (m, 9H), 2.81 (s, 3H), 2.16
(s, 3H), 2.01 (s, 3H). MS m/z (%) 287 (M+, 1), 256 (1), 222 (10),
188 (40), 171 (65), 155 (100).
1,1a ,6,6a -Tetr a h yd r oin d en o[1,2-b]a zir en -1-yl-4-m eth -
1-{N-(p-Tolylsu lfon yl)a m in o}in d a n e (Table 4; entry 2):
ylp h en yl su lfon e (Table 2, entry 3):22IR ν 3072, 2735, 2025,
14
IR ν 3246, 3047, 2968, 1730, 1400, 1125 cm-1 1H NMR δ
.
1115, 960 cm-1 1H NMR δ 7.70 (m, 4H), 6.92 (m, 4H), 5.42
.
7.80 (d, J ) 8.0 Hz, 2H), 7.40-7.10 (m, 6H), 5.00 (m, 1H), 4.62
(m, 1H), 3.20 (m, 1H), 3.15 (m, 1H), 2.42 (s, 3H), 2.30-1.60
(m, 2H). MS m/z (%), 287 (M+, 0.3), 149 (15), 133 (100), 115
(50), 91 (12), 77 (35).
(m, 3H), 3.50 (m, 1H), 3.10 (m, 1H), 2.70 (s, 3H). Mass, m/z
(%) 285 (10), 252 (40), 221 (35), 167 (60), 91 (100).
N-(p -Tolylsu lfon yl)-1,2,3,4-t et r a h yd r on a p h t h a len e-1,
2-a m in e (Table 2; entry 4):7c IR ν 1599, 1150, 1092, 990, 665
1
cm-1. H NMR δ 7.85 (d, J ) 8.5 Hz, 2H), 7.25-7.15 (m, 6H),
1-{N-(p-Tolylsu lfon yl)a m in o}-1-p h en yleth yl (Table 4;
1
entry 3):14 IR ν 3368, 3319, 2970, 1360, 752 cm-1. H NMR δ
3.80 (d, J ) 7.7 Hz, 1H), 3.55 (d, J ) 6.9 Hz, 1H), 2.70 (dt, J
) 15.5 and 5.2 Hz, 1H), 2.60 (dd, J ) 16.5 and 6.2 Hz, 1H),
2.49 (s, 3H), 2.32 (dd, J ) 15.2 and 5.3 Hz, 1H), 1.71 (dt, J )
13.7 and 5.4 Hz, 1H). MS m/z (%) 299 (M+, 1), 226 (1.5), 144
(100), 117 (67), 91 (32).
8.00 (s, 1H), 7.65 (d, J ) 4 Hz, 2H), 7.50-7.00 (m, 5H), 4.75
(d, J ) 6 Hz, 1H), 4.50 (m, 1H), 2.46 (s, 3H), 1.48 (d, J ) 8 Hz,
3H). MS m/z (%), 275 (M+, 0.5), 260 (95), 210 (1), 165 (1), 155
(48), 120 (50), 104 (30), 91 (100), 77 (22).
N-(p-Tolylsu lfon yl)-9-a za bicyclo[6.1.0]n on a n e (Table 2,
entry 5):7c IR ν 3028, 2982, 2936, 1600, 1498, 1160, 610 cm-1
.
Ack n ow led gm en t. We are grateful to CSIR, New
Delhi, for the award of a Pool Officership to A.V.B. and
a Senior Research Fellowship to R.V.
(21) Meguro, M.; Asao, N.; Yamamoto, Y. Tetrahedron Lett. 1994,
35, 7395.
(22) Shi, M.; Itoh, N.; Masaki, Y. J . Chem. Res (S) 1996, 352.
J O000013V