Aziridination of Activated Imines with Monocarbonyl Iodonium Ylides Generated from (Z)-(2-Acetoxyvinyl)iodonium Salts via Ester Exchange: Stereoselective Synthesis of 2-Acylaziridines

Article abstract of DOI:10.1021/jo982346m

Monocarbonyl iodonium ylides, generated in situ from (Z)-(2-acetoxyvinyl)iodonium salts via an ester exchange reaction with EtOLi, undergo alkylidene transfer reactions to activated imines yielding 2-acylaziridines in good yields. The stereochemical outcome of this aziridination was shown to be dependent on both the activating groups of the imines and the reaction solvents: that is, the aziridination of N-(2,4,6-trimethylbenzenesulfonyl)imines in THF affords cis-aziridines as a major product while that of N-benzoylimines in THF-DMSO or THF gives the trans isomer stereoselectively.

Full text of DOI:10.1021/jo982346m

J . Org. Chem. 1999, 64, 3181-3189
3181
Azir id in a tion of Activa ted Im in es w ith Mon oca r bon yl Iod on iu m
Ylid es Gen er a ted fr om (Z)-(2-Acetoxyvin yl)iod on iu m Sa lts via
Ester Exch a n ge: Ster eoselective Syn th esis of 2-Acyla zir id in es
Masahito Ochiai*,† and Yutaka Kitagawa
Faculty of Pharmaceutical Sciences, University of Tokushima, 1-78 Shomachi,
Tokushima 770-8505, J apan
Received November 30, 1998
Monocarbonyl iodonium ylides, generated in situ from (Z)-(2-acetoxyvinyl)iodonium salts via an
ester exchange reaction with EtOLi, undergo alkylidene transfer reactions to activated imines
yielding 2-acylaziridines in good yields. The stereochemical outcome of this aziridination was shown
to be dependent on both the activating groups of the imines and the reaction solvents: that is, the
aziridination of N-(2,4,6-trimethylbenzenesulfonyl)imines in THF affords cis-aziridines as a major
product while that of N-benzoylimines in THF-DMSO or THF gives the trans isomer stereoselec-
tively.
Sch em e 1
â-Dicarbonyl and â-disulfonyl iodonium ylides, rela-
tively stable species, are readily prepared in high yields
from the corresponding active methylene compounds by
the reaction with aryl-λ3-iodane in aqueous or alcoholic
alkali.1,2 Reactive intermediates generated by photo-
chemical and transition metal-catalyzed decomposition
of these stable iodonium ylides undergo several types of
reactions. These include cyclopropanation of olefins,
inter- and intramolecular carbon-hydrogen insertion
reaction, transylidation with various S, N, and P nucleo-
philes to give other ylides, carbonyl ylide formation, and
cycloaddition reactions leading to the formation of five-
membered heterocycles.3
characterized.1a Recently, we found that the ester ex-
change reaction between (Z)-(2-acetoxyvinyl)iodonium
bromides 1 (X ) Br) and EtOLi generates quantitatively
the monocarbonyl iodonium ylides 2 in THF at -78 °C
with the liberation of ethyl acetate (Scheme 1).4 The
monocarbonyl iodonium ylide 2b with n-octyl substituent
is stable up to -30 °C in THF, but gradually decomposes
at -20 °C to 1-bromo-2-decanone.
The stable iodonium ylides having â-dicarbonyl groups
possess a highly delocalized ylidic carbanion directly
bound to an aryliodonio group. Consequently, they exhibit
relatively low basicity and nucleophilicity, which, in turn,
renders these ylides inactive toward aldehydes and
Despite the increasing interest in and research on
these stable iodonium ylides, the chemistry of iodonium
ylides derived from unactivated monocarbonyl com-
pounds remains unknown, and no unstabilized mono-
carbonyl iodonium ylides have yet been isolated and
† Tel: 886-33-7281. Fax: 886-33-9504. E-mail: mochiai@
ph2.tokushima-u.ac.jp.
(1) For reviews of iodonium ylides, see: (a) Koser, G. F. The
Chemistry of Functional Groups, Supplement D; Wiley: New York,
1983; Chapter 18. (b) Varvoglis, A. Synthesis 1984, 709. (c) Moriarty,
R. M.; Vaid, R. K. Synthesis 1990, 431. (d) Varvoglis, A. The Chemistry
of Polycoordinated Iodine; VHC Publishers: New York, 1992; Chapter
6. (e) Stang, P. J .; Zhdankin, V. V. Chem. Rev. 1996, 96, 1123.
(2) For synthesis of â-dicarbonyl and â-disulfonyl iodonium ylides,
see: (a) Gudrinietse, E.; Neilands, O.; Vanag, G. J . Gen. Chem. USSR
1957, 27, 2777. (b) Neilands, O.; Vanag, G. J . Gen. Chem. USSR 1961,
31, 137. (c) Schank, K.; Lick, C. Synthesis 1983, 392. (d) Moriarty, R.
M.; Prakash, I.; Prakash, O.; Freeman, W. A. J . Am. Chem. Soc. 1984,
106, 6082. (e) Moriarty, R. M.; Bailey, B. R.; Prakash, O.; Prakash, I.
J . Am. Chem. Soc. 1985, 107, 1375.
(3) For reaction of stable iodonium ylides, see: (a) Koser, G. F.; Yu,
S.-M. J . Org. Chem. 1975, 40, 1166. (b) Hadjiarapoglou, L.; Spyroudis,
S.; Varvoglis, A. J . Am. Chem. Soc. 1985, 107, 7178. (c) Hadjiarapoglou,
L. P. Tetrahedron Lett. 1987, 28, 4449. (d) Hadjiarapoglou, L.;
Varvoglis, A. Synthesis 1988, 913. (e) Hadjiarapoglou, L.; Varvoglis,
A.; Alcock, N. W.; Pike, G. A. J . Chem. Soc., Perkin Trans. 1 1988,
2839. (f) Moriarty, R. M.; Prakash, O.; Vaid, R. K.; Zhao, L. J . Am.
Chem. Soc. 1989, 111, 6443. (g) Kang, J .; Lee, J . H.; Noh, S. B.; Oh, C.
S.; Kim, H. Y.; Chung, B. Y. Synlett 1990, 153. (h) Kalogiannis, S.;
Spyroudis, S. J . Org. Chem. 1990, 55, 5041. (i) Hackenberg, J .; Hanack,
M. J . Chem. Soc., Chem. Commun. 1991, 470. (j) Fairfax, D. J .; Austin,
D. J .; Xu, S. L.; Padwa, A. J . Chem. Soc., Perkin Trans. 1 1992, 2837.
(k) Yang, R.-Y.; Dai, L.-X.; Ma, R.-J . Heteroatom Chem. 1992, 3, 585.
(l) Spyroudis, S.; Tarantili, P. J . Org. Chem. 1993, 58, 4885. (m)
Moriarty, R. M.; Kim, J .; Guo, L. Tetrahedron Lett. 1993, 34, 4129. (n)
Kume, M.; Kubota, T.; Iso, Y. Tetrahedron Lett. 1995, 36, 8043. (o)
Muller, P.; Fernandez, D. Helv. Chim. Acta 1995, 78, 947.
(4) Ochiai, M.; Kitagawa, Y.; Yamamoto, S. J . Am. Chem. Soc. 1997,
119, 11598.
(5) For instance, the pKa value of phenyliodonium 4,4-dimethyl-2,6-
dioxocyclohexanide is 0.72. See: Kalnin, S. V.; Neilands, O. J . Org.
Chem. USSR 1971, 7, 1668.
(6) For recent reviews on the chemistry of aziridines, see: (a)
Tanner, D. Angew. Chem., Int. Ed. Engl. 1994, 33, 599. (b) Padwa, A.;
Woolhouse, A. D. In Comprehensive Heterocyclic Chemistry; Katritzky,
A. R., Rees, C. W., Eds.; Pergamon: Oxford, 1984; Vol. 7, pp 47-93.
(7) A part of this work has been reported in a preliminary form:
Ochiai, M.; Kitagawa, K. Tetrahedron Lett. 1998, 39, 5569.
(8) For synthesis of aziridines via the reaction of an imine with an
ylide, see: (a) Franzen, V.; Driesen, H.-E. Chem. Ber. 1963, 96, 1881.
(b) Corey, E. J .; Chaykovsky, M. J . Am. Chem. Soc. 1965, 87, 1353. (c)
Hortmann, A. G.; Robertson, D. A. J . Am. Chem. Soc. 1967, 89, 5974.
(d) Tewari, R. S.; Awasthi, A. K.; Awasthi, A. Synthesis 1983, 330. (e)
Matano, Y.; Yoshimune, M.; Suzuki, H. J . Org. Chem. 1995, 60, 4663.
(f) Zhu, Z.; Espenson, J . H. J . Org. Chem. 1995, 60, 7090. (g) Ruano,
J . L. G.; Fernandez, I.; Hamdouchi, C. Tetrahedron Lett. 1995, 36, 295.
(h) Li, A.-H.; Dai, L.-X.; Hou, X.-L.; Chen, M.-B. J . Org. Chem. 1996,
61, 4641. (i) Li, A.-H.; Dai, L.-X.; Hou, X.-L. J . Chem. Soc., Chem.
Commun. 1996, 491. (j) Casarrubios, L.; Perez, J . A.; Brookhart, M.;
Templeton, J . L. J . Org. Chem. 1996, 61, 8358. (k) Li, A.-H.; Dai, L.-
X.; Hou, X.-L. J . Chem. Soc., Perkin Trans. 1 1996, 867. (l) Aggarwal,
V. K.; Thompson, A.; J ones, R. V. H.; Standen, M. C. H. J . Org. Chem.
1996, 61, 8368. (m) Zhou, Y.-G.; Li, A.-H.; Hou, X.-L.; Dai, L.-X.
Tetrahedron Lett. 1997, 38, 7225. (n) Li, A.-H.; Zhou, Y.-G.; Dai, L.-
X.; Hou, X.-L.; Xia, L.-J .; Lin, L. Angew. Chem., Int. Ed. Engl. 1997,
36, 1317.
10.1021/jo982346m CCC: $18.00 © 1999 American Chemical Society
Published on Web 04/09/1999

3182 J . Org. Chem., Vol. 64, No. 9, 1999
Ochiai and Kitagawa
Ta ble 1. Rea ction of (Z)-(â-Acetoxyvin yl)iod on iu m Sa lt 1 w ith Im in e 3 in THF -DMSOa
iodonium
product (yieldb/%, ratioc)
conditions
temp/°C, time/h
entry
1
X
imine 3 (R1, R2)
3a (Ph, Ph)
4
5
6
1
2
3
4
5
6
7
8
9
1b
1b
1b
1b
1b
1b
1b
1b
1c
1a
1b
1b
1b
1c
1c
1c
Br
Br
Br
Br
BF4
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
-30, 2
-30, 2
-30, 2
-30, 2
-30, 2
0, 2
-30, 2
-30, 2
-30, 2
-30, 2
-30, 2
-30, 2
-30, 2
-30, 2
-30, 2
-30, 2
4ba (0)d
4ba (0)e
3b (Ph, SOC6H4-p-Me)
3c (Ph, SO2Ph)
3c
3c
3d (Ph, SO2C6H2-2,4,6-Me3)
3e (Ph, SO2Me)
3d
3f (Ph, CO2Me)
3f
3g (Ph, COPh)
3h (p-ClC6H4, COPh)
3f
3g
3h
4bb (3, -)f
4bc (78, 61:39)
4bc (76, 69:31)
4bc (74, 62:38)
4bd (85, 67:33)
4be (51, 36:64)
4cd (81, 18:82)
4a f (5, 100:0)
4bf (65, 100:0)
4bg (68, 98:2)
4bh (66, 92:8)
4cf (39, 83:17)
4cg (72, 93:7)
4ch (69, 92: 8)
10
11
12
13
14
15
16
6f (75)
6f (49)
6g (41)
6h (24)
6f (55)
6g (50)
6h (40)
5bg (9, 100:0)
5bh (22, 67:33)
5cg (7, 100:0)
5ch (16, 100:0)
a
b
Reactions were carried out using 1 equiv of EtOLi and 1.5 equiv of an imine 3 in THF-DMSO (12:1) under argon. Isolated yields.
c Trans:cis ratios, determined by 1H NMR of the crude product. Unsaturated 1,4-diketone 7 (82%, trans:cis ) 50:50) was obtained.
d
e 1,4-Diketone 7 (79%, trans:cis ) 42:58) was obtained. f -: not determined. 1,4-Diketone 7 (26%, trans:cis ) 43:57) was obtained.
Sch em e 2
ketones.1a,5 The monocarbonyl iodonium ylides 2, how-
ever, are moderately nucleophilic in nature and act as
an alkylidene transfer agent to carbonyl compounds.
Thus, the reaction with aldehydes in THF-DMSO (12:
1) at -30 °C gives R,â-epoxy ketones in good yields with
trans isomers as a major product.4
Aziridines are useful intermediates in organic synthe-
sis because of their chemical reactivity, mostly derived
from large ring strain.6 We report herein an addition
reaction of the monocarbonyl iodonium ylide 2 to imines
3, which provides a stereoselective route for the synthesis
of trans- and cis-2-acylaziridines 4.7,8
1b from Br to BF4 slightly increased the selectivity for
trans-aziridine 4bc. The reaction temperature appeared
to have no effect on the product profiles (entry 6).
Interestingly, the reaction of N-(methanesulfonyl)imine
3e with 1b resulted in reversal of the stereochemical
outcome, giving the cis-aziridine 4be as a major product,
albeit with low selectivity (compare entries 4 and 8). This
is the first example of the preparation of aziridines by
the addition of iodonium ylide to imines. Recently,
Matano and Suzuki reported the stereoselective synthesis
of R,â-aziridinyl ketones via the reaction of monocarbonyl
bismuthonium ylides with N-sulfonylimines.8e
Using carbonyl groups instead of sulfonyl groups to
increase the electrophilicity of the imines led to higher
trans selectivity for the formation of R,â-aziridino ketones
4: thus, the only detectable stereoisomer was found to
be trans-aziridine 4bf (65%) in the reaction of the
monocarbonyl iodonium ylide 2b with N-(methoxycar-
bonyl)imine 3f in THF-DMSO at -30 °C (entry 11). As
one of the byproducts, this reaction afforded the amino
acetal 6f (R1 ) Ph, R2 ) CO2Me) in 49% yield, presumably
produced by nucleophilic attack of EtOLi to 3f. A similar
stereochemical outcome was obtained in the reaction with
N-benzoylimine 3g, which gave a 98:2 mixture of trans-
and cis-2-acylaziridines 4bg in 68% yield. In addition to
the amino acetal 6g (41%), a small amount of trans-2-
phenyl-2-oxazoline 5bg (R ) n-C8H17, R1 ) Ph; 9%) was
obtained in this reaction. The reaction of (Z)-(2-acetoxy-
1-propenyl)iodonium bromide 1a with N-(methoxycar-
bonyl)imine 3f in THF-DMSO resulted in poor yield of
aziridine 4a f (5%) and also the formation of a large
amount of the amino acetal 6f (75%), which is probably
due to poor solubility of the iodonium salt 1a under these
Resu lts a n d Discu ssion
Azir id in a tion in THF -DMSO. No alkylidene trans-
fer reaction of the ylide 2b with N-benzylideneaniline (3a )
was observed. Reaction of (Z)-(2-acetoxy-1-decenyl)(phen-
yl)iodonium bromide (1b) with 3a in THF-DMSO (12:1)
at -30 °C afforded a 1:1 mixture of (E)- and (Z)-10-
eicosene-9,12-dione 7 in 82% yield with no evidence of
the formation of aziridinyl ketone 4ba . This result is
probably due to the low electrophilicity of the N-arylimine
3a .9 Dimerization of the ylide 2b explains the formation
of the unsaturated 1,4-diketone 7; in fact, when the imine
3a was not added, the reaction of 1b with EtOLi gave 7
(79%, E:Z ) 42:58) (Table 1, entry 2).10
The same trend holds for the reaction with the more
reactive N-sulfinylimine 3b (entry 3); however, the direct
aziridination of CdN bonds took place smoothly when
activated N-sulfonylaldimines were employed. Treatment
of a THF-DMSO (12:1) solution of vinyliodonium bro-
mide 1b and N-(benzenesulfonyl)benzaldimine (3c) (1.5
equiv) with 1 equiv of EtOLi at -30 °C for 2 h resulted
in the formation of a stereoisomeric mixture of R,â-
aziridino ketone 4bc (R ) n-C8H17, R1 ) Ph, R2 ) SO2-
Ph) in 78% yield (Scheme 2). The trans:cis ratio was
determined to be 61:39 by 1H NMR analysis of the crude
product (entry 4). Changing the ligand on iodine(III) of
(9) The reported semiempirical AM1 calculations of the atomic net
charges of benzaldehyde, N-benzylideneaniline 3a , and N-tosylimine
3j predict the following order of reactivity toward nucleophiles, PhCHd
NTs 3j > PhCHO > PhCHdNPh 3a . See ref 8h.
(10) Reaction of 1b with EtOLi in THF-DMSO at -30 °C in the
presence of styrene (10 equiv) yielded no the addition products, i.e.,
cyclopropanes, and gave 7 (55%, E:Z ) 43:57).

Stereoselective Synthesis of 2-Acylaziridines
J . Org. Chem., Vol. 64, No. 9, 1999 3183
Ta ble 2. Rea ction of (Z)-(â-Acetoxyvin yl)iod on iu m Sa lt 1 w ith Im in e 3 in THF a
iodonium
product (yieldb/%, ratioc)
conditions
temp, °C
entry
1
X
imine 3 (R1, R2)
4
5
6
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
1a
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1b
1c
1c
1c
1b
1b
BF4
Br
BF4
BF4
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
Br
3d (Ph, SO2C6H2-2,4,6-Me3)
3c (Ph, SO2Ph)
3c
3c
3d
-78 f 25
-78 f 25
-78 f 25
25d
4a d (22, 80:20)
4bc (73, 31:69)
4bc (67, 75:25)
4bc (47, 78:22)
4bd (73, 15:85)
4be (74, 25:75)
4bi (83, 27:73)
4bj (64, 29:71)
4bk (59, 37:63)
4bl (68, 35:65)
4bm (82, 18:82)
4bn (76, 18:82)
4bo (65, 44:56)
4bp (67, 31:69)
4bq (80, 14:86)
4br (36, 19:81)
4cd (83, 5:95)
4cm (85, 8:92)
4cn (89, 5:95)
4bf (50, 100:0)
4bg (60, 90:10)
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
-78 f 25
3e (Ph, SO2Me)
3i (Ph, SO2C6H4-p-OMe)
3j (Ph, SO2C6H4-p-Me)
3k (Ph, SO2C6H4-p-Cl)
3l (Ph, SO2-2-naphthyl)
3m (p-MeC6H4, SO2C6H2-2,4,6-Me3)
3n (p-ClC6H4, SO2C6H2-2,4,6-Me3)
3o (1-naphthyl, SO2Ph)
3p (2-naphthyl, SO2Ph)
3q (2-naphthyl, SO2C6H2-2,4,6-Me3)
3r (t-Bu, SO2C6H2-2,4,6-Me3)
3d
3m
3n
3f (Ph, CO2Me)e
6f (98)
6g (42)
3g (Ph, COPh)
5bg (12)
a
b
Reactions were carried out using 1 equiv of EtOLi and 1.5 equiv of an imine 3 in THF under argon. Isolated yields. c Trans:cis
ratios, determined by 1H NMR of the crude product. Reaction time, 2 h. e 3 equiv of imine 3f were used.
d
conditions. The reaction of the monocarbonyl iodonium
ylide 2c with sterically demanding tert-butyl group with
imines 3f-h activated by carbonyl groups selectively
afforded trans-aziridines 4cf-ch in moderate to good
yields (entries 14-16).
The stereochemistry of the R,â-aziridino ketones 4 was
easily determined by 1H NMR: the typical coupling
constant for the vicinal ring hydrogens of cis-aziridines
4 is about 7 Hz whereas the value for the trans ring
hydrogens is much smaller (about 2.4-4.3 Hz).6b Iden-
tification of 2-phenyl-2-oxazolines 5 was made possible
by comparing their NMR data with data of similar
compounds.11 The stereochemistry of 5 was determined
by the vicinal coupling constants between the ring
hydrogens, C4-H and C5-H: 6.8 Hz for trans-5bg, 6.8
Hz for trans-5bh , 11.0 Hz for trans-5bh .
Azir id in a tion in THF . The results of alkylidene
transfer of the ylides 2 to a CdN bond of the activated
imines 3 in THF are summarized in Table 2. In general,
the reactions were carried out simply by adding an
equivalent amount of EtOLi to a THF solution of vinyli-
odonium salts 1 and imines 3 (1.5 equiv) at -78 °C. After
being stirred for 2 h, the mixture was allowed to warm
to ambient temperature. R,â-Aziridino ketones 4 were
obtained after workup. Whereas the reaction of vinyli-
odonium bromide 1b with N-(benzenesulfonyl)imine 3c
in THF-DMSO gave predominantly the trans-aziridine
4bc (entry 4), the aziridination in THF gave the cis
isomer as the major product with trans:cis ratio of 31:69
(entry 18). Interestingly, changing the ligand on iodine-
(III) of 1b from Br to BF4 was found to reverse the
stereochemistry of the major product from cis to trans
(entry 19).12
2-acylaziridines 4 was observed when N-(2,4,6-trimeth-
ylbenzenesulfonyl)aldimine 3d was used (entry 21).
Similar levels of cis-selectivity (81-86%) were obtained
in the reaction of vinyliodonium bromide 1b with other
aromatic 3m ,n ,q and aliphatic N-sulfonylaldimines 3r
having a mesitylenesulfonyl group on the nitrogen. The
effect of this mesitylenesulfonyl group was confirmed
again by the reaction of (Z)-(2-acetoxy-3,3-dimethyl-1-
butenyl)(phenyl)iodonium bromide (1c), which led to
more than 90% cis-selectivity (entries 33-35).
The trans/ cis selectivity in the aziridination of imines
activated with carbonyl groups seems to be independent
of the nature of the solvents. Thus, changing the solvent
from THF-DMSO to THF in the reaction of imines 3f,g
with vinyliodonium bromide 1b did not lead to a signifi-
cant change in the stereochemical outcome of the aziri-
dination (compare entries 11, 12, 36, and 37).
Thus, the reaction of the monocarbonyl iodonium ylide
2 with the N-(2,4,6-trimethylbenzenesulfonyl)imines in
THF gives cis-R,â-aziridino ketones as a major product,
while the reaction with N-benzoylimines in THF-DMSO
or THF gives trans-R,â-aziridino ketones.
Su b st it u en t E ffect on R ea ct ivit y of N-Su lfo-
n ylim in es. To gain some insight into the mechanism of
the aziridination of aldimines with monocarbonyl iodo-
nium ylides, we measured the relative rates of the
alkylidene transfer reaction of the ylide 2b for a series
of ring-substituted N-(arenesulfonyl)benzaldimines 3c
and 3i-k in THF in which a mixture of a 10-fold excess
of each of two competing imines was used. Electron-
donating p-MeO and p-Me groups decreased the rate of
the reaction, and the electron-withdrawing p-Cl substitu-
ent increased it (the effect of substituents on the rate of
aziridination is shown in Table 3). A Hammett plot for
the alkylidene transfer reaction presented in Table 3
Introduction of the electron-donating p-MeO and p-Me
groups on the benzenesulfonyl group of 3c slightly
increased the cis-selectivity while that of the electron-
withdrawing p-Cl substituent decreased the cis-selectiv-
ity. The higher cis-selectivity (85%) for the synthesis of
(12) The reasons for the influence of the counterion of the iodonium
salt on the stereochemistry of the reaction is not clear. For similar
effects of counteranion, see: (a) Bergelson, L. D.; Barsukov, L. I.;
Shemayakin, M. M. Tetrahedron Lett. 1967, 23, 2709. (b) Still, W. C.;
Novack, V. J . J . Am. Chem. Soc. 1981, 103, 1283. (c) Ward, W. J .;
McEwen, W. E. J . Org. Chem. 1990, 55, 493. (d) Bellucci, G.; Chiappe,
C.; Moro, G. L. Tetrahedron Lett. 1996, 37, 4225.
(11) (a) Pines, S. H.; Kozlowski, M. A.; Karady, S. J . Org. Chem.
1969, 34, 1621. (b) Heine, H. W.; Kaplan, M. S. J . Org. Chem. 1967,
32, 3069.

3184 J . Org. Chem., Vol. 64, No. 9, 1999
Ochiai and Kitagawa
Ta ble 3. Rela tive Rea ctivity of Su lfon ylim in es 3 w ith 2b
in THF
substrate
krel
substrate
krel
3i (p-MeO)
3j (p-Me)
0.56
0.84
3c (H)
3k (p-Cl)
1.0
1.82
Sch em e 3
showed a linear correlation of relative rate factors with
the σ constants of substituents in the aromatic ring and
afforded the reaction constant F ) 0.96 (r ) 0.98).13 This
small positive F value indicates moderate nucleophilicity
of the monocarbonyl iodonium ylide 2b, which is in a good
agreement with the results obtained for the reaction of
2b with a series of substituted benzaldehydes yielding
R,â-epoxy ketones.4
F igu r e 1. Linear free energy relationship for trans/cis ste-
reoselectivity on aziridination of N-(arenesulfonyl)imines 3c
and 3i-k with iodonium ylide 2b in THF.
Sch em e 4
Rea ction Mech a n ism . One of the possible reaction
mechanisms that should be considered, and which was
also discussed in our previous paper,4 involves base-
induced R-vinylic proton abstraction of (Z)-(â-acetoxyvi-
nyl)iodonium salt 1 with EtOLi, yielding the vinyliodo-
nium ylides which, in turn, react with imines 3 to give
the 2-acylaziridines 4.14 The following results, however,
clearly indicate that this R-proton abstraction does not
occur; the R-deuterated vinyliodonium salt 1b-Rd, on
treatment with EtOLi in the presence of N-(benzene-
sulfonyl)benzaldimine (3c) (1.5 equiv) and ethanol (5
equiv) in THF-DMSO at -30 °C, afforded the R,â-
aziridino ketone 4bc-Rd (59%, trans/ cis ) 55:45), in
which 84% of the deuterium was retained (Scheme 3).
Under these conditions, the R-proton abstraction mech-
anism predicts loss of most of the deuterium because of
kinetic deuterium isotope effects on protonation from
ethanol.
sulfonyl)benzaldimines 3c and 3i-k (Table 3) suggest
that the nucleophilic attack of the ylide carbanion on the
activated imines 3 will probably be a rate-limiting step
in this alkylidene transfer reaction in THF.
The mechanism of the reaction presumably involves
nucleophilic attack of the in situ generated monocarbonyl
iodonium ylides 2 via an ester exchange reaction (shown
in Scheme 1) on the imine 3, which produces the
zwitterion 8 (Scheme 4). Subsequent intramolecular
reductive cyclization by nucleophilic attack of the nitro-
gen yields the aziridines 4 with concomitant liberation
of iodobenzene. The latter step may compete with an
alternative intramolecular cyclization via attack of the
nucleophilic oxygen, yielding the byproducts 2-oxazolines
5 when N-(benzoyl)imines 3g,h are used. Because of the
very high nucleofugality of the phenyliodonio group
(about 106 times greater than triflate,15 a so-called
superleaving group), it seems reasonable to assume that
these intramolecular reductive cyclizations of the zwit-
terion 8 might be very fast and, therefore, the reverse
reaction of 8 regenerating the monocarbonyl iodonium
ylides 2 will not be important. Furthermore, the relative
rate studies for a series of ring-substituted N-(arene-
As was described above, the electron-donating para
substituents of N-sulfonylimines 3i,j slightly increased
the cis-aziridine selectivity when the reaction with the
ylide 2b was carried out in THF whereas lower cis-
selectivity resulted from the presence of an electron-
withdrawing substituent, i.e., 3k (Table 2, entries 18 and
23-25). Using the method developed by Braun and
Opdenbusch,16 the difference of the logarithms of the
stereoisomeric ratios of substituted and unsubstituted
products [log(4bi-bk cis/4bi-bk trans) - log(4bccis/4bctrans)]
is plotted against Hammett σ constants, which shows a
good linear relationship with r ) 0.99 (Figure 1). As
indicated in Figure 1, cis-selectivity clearly decreases
with an increase in the electron-withdrawing nature of
the para substituent.
Scheme 5 represents a mechanistic proposal that is
compatible with these stereochemical outcomes. The
electron-donating para substituent of N-sulfonylimine 3i,
by enhancing the electron density of the sulfonyl oxygen,
will lead to a more tightened transition state 9 in THF,
wherein one of the sulfonyl oxygen atoms is coordinated
to the positively charged iodine(III) of the ylide. Coordi-
nation of both sulfonyl oxygen atoms to the charged
iodine(III) is a possible alternative. The degree of the
tightness in this transition state 9 might control stereo-
(13) Hammett, L. P. J . Am. Chem. Soc. 1937, 59, 96.
(14) (a) Stang, P. J .; Wingert, H.; Arif, A. M. J . Am. Chem. Soc. 1987,
109, 7235. (b) Ochiai, M.; Kunishima, M.; Fuji, K.; Shiro, M.; Nagao,
Y. J . Chem. Soc., Chem. Commun. 1988, 1076. (c) Ochiai, M.; Takaoka,
Y.; Nagao, Y. J . Am. Chem. Soc. 1988, 110, 6565. (d) Ochiai, M.;
Kunishima, M.; Tani, S.; Nagao, Y. J . Am. Chem. Soc. 1991, 113, 3135.
(e) Ochiai, M.; Sueda, T.; Uemura, K.; Masaki, Y. J . Org. Chem. 1995,
60, 2624.
(15) Okuyama, T.; Takino, T.; Sueda, T.; Ochiai, M. J . Am. Chem.
Soc. 1995, 117, 3360.
(16) Braun, M.; Opdenbusch, K. Liebigs Ann. Recl. 1997, 141.

Stereoselective Synthesis of 2-Acylaziridines
J . Org. Chem., Vol. 64, No. 9, 1999 3185
Sch em e 5
Sch em e 7
supported by the recent observations that irradiation or
heating of the stable iodonium ylide 11 in DMSO gave a
1:1 complex 12 (Scheme 7, the structure of which was
confirmed by X-ray diffraction analysis.21 Tight hyper-
valent interaction between the iodine atom and the
oxygen atom of DMSO makes the adduct 12 stable at
room temperature.
Sch em e 6
In conclusion, our results demonstrate that the mono-
carbonyl iodonium ylide 3 is moderately nucleophilic in
nature and undergoes stereoselective alkylidene transfer
reaction to the CdN bond of the activated aldimines.
Exp er im en ta l Section
selectivity for aziridination of N-sulfonylimines 3 in THF,
since 9 produces syn zwitterion 8 which, in turn, fur-
nishes the cis-2-acylaziridines 4. On the other hand, it
seems reasonable to assume that such a coordination of
the carbonyl oxygen atom of N-(methoxycarbonyl)imine
3f and N-benzoylimine 3g to the iodine(III) is not
important. We have reported that observation of a
negative NOE between R-methine and γ-methylene
protons at - 70 °C in THF-d8 suggests a preference for
the cisoid conformation in 2b,4 as was observed in other
monocarbonyl onium (P, S, and As) ylides in solution17
and/or in a solid state.18 Intramolecular interaction
between the charged iodine(III) and the carbonyl oxygen
in 2b will stabilize this cisoid conformation.19 Trapping
experiments with benzoyl chloride confirmed the cisoid
conformation in 2b.4
An alternative explanation is that these electronic
effects on trans/ cis stereoselectivity result from changes
imparted by the para substituents on the reactivity of
the N-sulfonylimines 3. The p-MeO substituent of 3i
decreases the rate of aziridination with the ylide 2b to
one-half (Table 3), and this less reactive imine 3i would
be expected to react with 2b via a more product-like
transition state compared to the unsubstituted imine 3c,
resulting in more severe nonbonded interactions that lead
to higher cis/ trans stereoselectivity.
For the reactions in THF-DMSO, we propose an anti
transition state 10 (see Scheme 6), which can be expected
to produce the trans-2-acylaziridines 4 as a major product
via the intervention of anti zwitterion 8. This mechanism
accounts for the trans/ cis stereoselectivity shown in
Table 1.
In the presence of DMSO in excess, coordination of the
sulfonyl oxygen atom of the N-sulfonylimines 3 to the
charged iodine(III) of the ylide 2 will, as in 9, no longer
participate. Rather, because of the excellent solvent
donicity of DMSO (DN ) 29.8),20 the oxygen atom of
DMSO will coordinate to the positively charged iodine-
(III) of the ylide 2, making coordination of the sulfonyl
oxygen atoms of 3 difficult. These hypotheses were
Gen er a l. For general experimental details, see ref 4.
Preparative thin-layer chromatography (TLC) was carried out
on precoated plates of silica gel (Merck, silica gel F-254).
Kieselgel 60 (Merck, 230-400 mesh) was used for flash
chromatography.
(Z)-(2-Acetoxy-1-alkenyl)(phenyl)iodonium bromides (1a -
c: X ) Br) were prepared from 1-alkynyl(phenyl)iodonium
tetrafluoroborates22 via Michael addition of acetic acid in the
presence of sodium acetate according to literature procedure.4
N-Sulfonylimines 3c-d and 3i-r were prepared according to
literature methods.15,23 N-(Methoxycarbonyl)imine 3f 24 and
N-benzoylimines 3g,h 25 were obtained by a literature proce-
dure.
Syn th esis of (Z)-(2-Acetoxy-1-p r op en yl)(p h en yl)iod o-
n iu m Tetr a flu or obor a te (1a : X ) BF 4). (Z)-(2-Acetoxy-1-
propenyl)(phenyl)iodonium bromide (1a : X ) Br) (80 mg, 0.21
mmol) was dissolved in dichloromethane (15 mL), and the
solution was vigorously shaken with a saturated aqueous
sodium tetrafluoroborate solution (5 mL) five times. The
organic layer was filtered and concentrated under aspirator
vacuum to give an oil, which was washed several times with
hexane by decantation at -78 °C to give (Z)-(â-acetoxyvinyl)-
iodonium tetrafluoroborate (1a : X ) BF4, 71 mg, 87%) as
colorless needles: mp 88-89 °C (recrystallized from dichlo-
romethane-THF); IR (KBr) 1770, 1639, 1473, 1188, 1128, 742
cm-1; 1H NMR (CDCl3) δ 7.97 (br d, J ) 8.5 Hz, 2H), 7.66 (br
t, J ) 7.3 Hz, 1H), 7.51 (br dd, J ) 8.5, 7.3 Hz, 2H), 6.51 (q, J
) 1.0 Hz, 1H), 2.40 (d, J ) 1.0 Hz, 3H), 2.29 (s, 3H); FAB MS
m/z 303 [(M - BF4)+]. Anal. Calcd for C11H12BF4IO2: C, 33.88;
H, 3.10. Found: C, 33.79; H, 3.07.
Syn th esis of (Z)-(2-Acetoxy-1-d ecen yl)(p h en yl)iod o-
n iu m Tetr a flu or obor a te (1b: X ) BF 4). In
manner, (Z)-(â-acetoxyvinyl)iodonium tetrafluoroborate (1b: X
) BF4) was prepared in 98% yield from (Z)-(2-acetoxy-1-
decenyl)(phenyl)iodonium bromide (1b: X ) Br) (420 mg, 0.87
mmol): white powder; mp 58-60 °C (recrystallized from
a similar
(21) Bond length of I-O of the adduct 12 is 2.59(2) Å. See: Zhu,
S.-Z. Heteroatom Chem. 1994, 5, 9.
(22) Ochiai, M.; Kunishima, M.; Sumi, K.; Nagao, Y.; Fujita, E.
Tetrahedron Lett. 1985, 26, 4501.
(23) (a) Vishwakarma, L. C.; Stinger, O. D.; Davis, F. A. Org. Synth.
1987, 66, 203. (b) J enning, W. B.; Lovely, C. J . Tetrahedron 1991, 47,
5561. (c) Davis, F. A.; Lamendola, J r., J .; Nadir, U.; Kluger, E. W.;
Sedergran, T. C.; Panunto, T. W.; Billmers, R.; J enkins, R., J r.; Turchi,
I. J .; Watson, W. H.; Chen, J . S.; Kimura, M. J . Am. Chem. Soc. 1980,
102, 2000. (d) Albrecht, R.; Kresze, G.; Mlakar, B. Chem. Ber. 1964,
97, 483. (e) Hart, D. J .; Kanai, K.; Thomas, D. G.; Yang, T.-K. J . Org.
Chem. 1983, 48, 289. (f) Georg, G. I.; Harriman, G. C. B.; Peterson, S.
A. J . Org. Chem. 1995, 60, 7366.
(17) (a) Casanova, J .; Rutolo, D. A. J . Chem. Soc., Chem. Commun.
1967, 1224. (b) Smallcombe, S. H.; Holland, R. J .; Fish, R. H.; Caserio,
M. C. Tetrahedron Lett. 1968, 5987.
(18) Shao, M.; J in, X.; Tang, Y. Tetrahedron Lett. 1982, 23, 5343.
(19) (a) Druck, U.; Littke, W. Acta Crystallogr. 1978, B34, 3092. (b)
Alcock, N. W. Acta Crystallogr. 1990, C46, 1300.
(24) Kupfer, R.; Meier, S.; Wu¨rthwein, E.-U. Synthesis 1984, 688.
(25) Breuer, S. W.; Bernath, T.; Ben-Ishai, D. Tetrahedron 1967,
23, 2869.
(20) Gutmann, V. Chemtech 1977, 255.

3186 J . Org. Chem., Vol. 64, No. 9, 1999
Ochiai and Kitagawa
dichloromethane-hexane); IR (KBr) 1763, 1639, 1474, 1372,
tallized from dichloromethane-hexane); IR (KBr) 1721, 1320,
1151 cm-1; 1H NMR (CDCl3) δ 7.38-7.28 (m, 5H), 4.13 (d, J )
8.1 Hz, 1H), 3.74 (d, J ) 8.1 Hz, 1H), 3.22 (s, 3H), 2.24 (dt, J
) 17.2, 7.4 Hz, 1H), 2.17 (dt, J ) 17.2, 7.4 Hz, 1H), 1.60-0.90
(m, 12H), 0.86 (t, J ) 6.7 Hz, 3H); MS m/z (relative intensity)
337 (2, M+), 258 (100), 158 (44); HRMS calcd for C18H27NO3S
(M+) 337.1712, found 337.1703.
1189 cm-1 1H NMR (CDCl3) δ 7.99 (br d, J ) 8.1 Hz, 2H),
;
7.64 (br t, J ) 7.1 Hz, 1H), 7.48 (br dd, J ) 8.1, 7.1 Hz, 2H),
6.61 (s, 1H), 2.64 (t, J ) 7.6 Hz, 2H), 2.28 (s, 3H), 1.61-1.42
(m, 2H), 1.40-1.18 (m, 10H), 0.87 (t, J ) 6.3 Hz, 3H); FAB
MS m/z 575 [(M + BF4)+]. Anal. Calcd for C18H26BF4IO2: C,
44.29; H, 5.37. Found: C, 44.18; H, 5.29.
N-(2,4,6-Tr im eth ylben zen esu lfon yl)-2-(2,2-d im eth y1-
1-oxop r op yl)-3-p h en yla zir id in e (4cd ): colorless oil (trans:
cis ) 16:84); IR (CHCl3) 1715, 1600, 1330, 1160 cm-1; 1H NMR
(CDCl3) δ 7.33-7.23 (m, 5H), 6.97 (s, cis isomer), 6.90 (s, trans
isomer), 4.38 (d, J ) 4.2 Hz, trans isomer), 4.22 (d, J ) 7.6
Hz, cis isomer), 4.06 (d, J ) 7.6 Hz, cis isomer), 3.95 (d, J )
4.2 Hz, trans isomer), 2.79 (s, cis isomer), 2.58 (s, trans isomer),
2.29 (s, 3H), 1.28 (s, trans isomer), 0.95 (s, cis isomer); MS
m/z (relative intensity) 385 (1, M+), 202 (100), 160 (43); HRMS
calcd for C22H27NO3S (M+) 385.1712, found 385.1718.
tr a n s-N-Ca r b om et h oxy-2-a cet yl-3-p h en yla zir id in e
Gen er a l P r oced u r e for Syn th esis of 2-Acyla zir id in es
4 in THF -DMSO. A Typ ica l Exa m p le (Ta ble 1, En tr y 4):
N-(Ben zen esu lfon yl)-2-(1-oxon on yl)-3-p h en yla zir id in e
(4bc). To a stirred solution of (Z)-(2-acetoxy-1-decenyl)iodo-
nium bromide (1b: X ) Br, 30 mg, 0.062 mmol) and N-
(benzenesulfonyl)benzaldimine (3c) (23 mg, 0.094 mmol) in
THF-DMSO (12:1, 6.5 mL) was added a 0.43 M THF solution
of EtOLi (0.14 mL, 0.062 mmol) at -30 °C under argon. The
solution immediately turned pale yellow. After being stirred
for 2 h, the mixture was quenched with water and extracted
with diethyl ether. The organic phase was washed with brine,
dried over anhydrous Na2SO4, and concentrated. The trans:
cis ratio of 2-acylaziridines 4bc was determined to be 69:31
by 1H NMR of the crude reaction mixture. Preparative TLC
(25% ethyl acetate in hexane) of the crude material using silica
gel gave a mixture of trans- and cis-4bc (19.4 mg, 78%), in
which isomerization of trans-4bc to the more stable cis isomer
makes it difficult to isolate pure trans-4bc to some extent.26
4bc (trans:cis ) 50:50); IR (CHCl3) 1720, 1335, 1165 cm-1; 1H
NMR (CDCl3) δ 8.06 (br d, J ) 8.2 Hz, cis isomer), 7.84 (br d,
J ) 8.1 Hz, trans isomer), 7.71-7.42 (3H), 7.35-7.17 (m, 5H),
4.30 (d, J ) 4.3 Hz, trans isomer), 4.18 (d, J ) 7.8 Hz, cis
isomer), 3.74 (d, J ) 4.3 Hz, trans isomer), 3.67 (d, J ) 7.8
Hz, cis isomer), 2.62 (t, J ) 7.1 Hz, trans isomer), 2.12 (dt, J
) 18.1, 7.8 Hz, cis isomer), 1.94 (dt, J ) 18.1, 7.8 Hz, cis
isomer), 1.70-0.80 (m, 15H). Anal. Calcd for C23H29NO3S: C,
69.14; H, 7.32; N, 3.51. Found: C, 69.43; H, 7.58; N, 3.44. Pure
cis-4bc was obtained by repeated preparative TLC (15% ethyl
acetate in hexane). cis-4bc: colorless crystals; mp 39-40 °C
(recrystallized from dichloromethane-hexane); IR (KBr) 1723,
1342, 1312, 1164 cm-1; 1H NMR (CDCl3) δ 8.06 (br d, J ) 8.3
Hz, 2H), 7.71 (br t, J ) 7.2 Hz, 1H), 7.60 (br dd, J ) 8.3, 7.2
Hz, 2H), 7.35-7.17 (m, 5H), 4.18 (d, J ) 7.8 Hz, 1H), 3.67 (d,
J ) 7.8 Hz, 1H), 2.12 (dt, J ) 18.1, 7.8 Hz, 1H), 1.94 (dt, J )
18.1, 7.1 Hz, 1H), 1.63-0.90 (m, 12H), 0.86 (t, J ) 6.7 Hz,
3H); MS m/z (relative intensity) 399 (1, M+), 258 (20), 115
(100); HRMS calcd for C23H29NO3S (M+) 399.1868, found
399.1845.
(tr a n s-4a f): colorless oil; IR (CHCl3) 1725, 1440, 1320 cm-1
;
1H NMR (CDCl3) δ 7.43-7.25 (m, 5H), 3.78 (s, 3H), 3.69 (d, J
) 2.4 Hz, 1H), 3.35 (d, J ) 2.4 Hz, 1H), 2.39 (s, 3H); MS m/z
(relative intensity) 219 (58, M+), 176 (91), 118 (100); HRMS
calcd for C12H13NO3 (M+) 219.0895, found 219.0898.
tr a n s-N-Ca r bom eth oxy-2-(1-oxon on yl)-3-p h en yla zir i-
d in e (tr a n s-4bf): colorless oil; IR (CHCl3) 1730, 1320 cm-1
;
1H NMR (CDCl3) δ 7.41-7.26 (m, 5H), 3.77 (s, 3H), 3.68 (d, J
) 2.4 Hz, 1H), 3.32 (d, J ) 2.4 Hz, 1H), 2.65 (t, J ) 7.2 Hz,
2H), 1.77-1.55 (m, 2H), 1.42-1.19 (m, 10H), 0.88 (t, J ) 6.8
Hz, 3H); MS m/z (relative intensity) 317 (100, M+), 258 (34),
176 (83); HRMS calcd for C19H27NO3 (M+) 317.1991, found
317.1971. Anal. Calcd for C19H27NO3‚1/4H2O: C, 70.89; H, 8.61;
N, 4.35. Found: C, 70.94; H, 8.78; N, 4.15.
tr a n s-N-Ben zoyl-2-(1-oxon on yl)-3-p h en yla zir id in e
(tr a n s-4bg): colorless needles; mp 51-52 °C (recrystallized
from dichloromethane-hexane); IR (CHCl3) 1705, 1675, 1320
1
cm-1; H NMR (CDCl3) δ 7.89 (br d, J ) 8.5 Hz, 2H), 7.55-
7.26 (m, 8H), 3.87 (d, J ) 2.3 Hz, 1H), 3.58 (d, J ) 2.3 Hz,
1H), 2.60 (t, J ) 7.3 Hz, 2H), 1.75-1.45 (m, 2H), 1.40-1.10
(m, 10H), 0.87 (t, J ) 6.3 Hz, 3H); MS m/z (relative intensity)
363 (23, M+), 258 (31), 105 (100); HRMS calcd for C24H29NO2
(M+) 363.2198, found 363.2210. Anal. Calcd for C24H29NO2: C,
79.30; H, 8.04; N, 3.85. Found: C, 79.50; H, 8.22; N, 3.80.
cis-N-Ben zoyl-2-(1-oxon on yl)-3-p h en yla zir id in e (cis-
4bg): colorless needles; mp 76-77 °C (recrystallized from
dichloromethane-hexane); IR (CHCl3) 1715, 1675, 1280 cm-1
;
1H NMR (CDCl3) δ 8.08 (br d, J ) 8.5 Hz, 2H), 7.60-7.26 (m,
8H), 4.02 (d, J ) 7.0 Hz, 1H), 3.73 (d, J ) 7.0 Hz, 1H), 2.33-
2.23 (m, 2H), 1.45-0.90 (m, 12H), 0.86 (t, J ) 6.7 Hz, 3H);
MS m/z (relative intensity) 363 (9, M+), 105 (100); HRMS calcd
for C24H29NO2 (M+) 363.2198, found 363.2198.
N-(2,4,6-Tr im eth ylben zen esu lfon yl)-2-(1-oxon on yl)-3-
p h en yla zir id in e (4bd ): colorless oil (trans:cis ) 12:88); IR
(CHCl3) 1710, 1605, 1330, 1165 cm-1; 1H NMR (CDCl3) δ 7.35-
7.15 (m, 5H), 7.01 (s, cis isomer), 6.91 (s, trans isomer), 4.30
(d, J ) 4.2 Hz, trans isomer), 4.19 (d, J ) 7.8 Hz, cis isomer),
3.72 (d, J ) 4.2 Hz, trans isomer), 3.64 (d, J ) 7.8 Hz, cis
isomer), 2.79 (s, cis isomer), 2.62 (t, J ) 7.1 Hz, trans isomer),
2.58 (s, trans isomer), 2.33 (s, cis isomer), 2.29 (s, trans isomer),
2.11 (dt, J ) 17.1, 7.1 Hz, cis isomer), 1.92 (dt, J ) 17.1, 7.1
Hz, cis isomer), 1.66-0.78 (m, 15H); MS m/z (relative intensity)
441 (1, M+), 258 (100); HRMS calcd for C26H35NO3S (M+)
441.2338, found 441.2333. Anal. Calcd for C26H35NO3S: C,
70.71; H, 7.99; N, 3.17. Found: C, 70.62; H, 8.07; N, 2.91.
N -(Me t h a n e su lfon yl)-2-(1-oxon on yl)-3-p h e n yla zir i-
d in e (4be): colorless plates (trans:cis ) 39:61); recrystallized
from dichloromethane-hexane; IR (CHCl3) 1720, 1330, 1155
tr a n s-N-Ben zoyl-3-(4-ch lor oph en yl)-2-(1-oxon on yl)azir -
id in e (tr a n s-4bh ): colorless needles; mp 61-62 °C (recrystal-
lized from dichloromethane-hexane); IR (KBr) 1709, 1673,
1328 cm-1 1H NMR (CDCl3) δ 7.87 (br d, J ) 8.6 Hz, 2H),
;
7.56-7.20 (m, 7H), 3.85 (d, J ) 2.4 Hz, 1H), 3.54 (d, J ) 2.4
Hz, 1H), 2.60 (t, J ) 7.3 Hz, 2H), 1.70-1.45 (m, 2H), 1.40-
1.15 (m, 10H), 0.87 (t, J ) 7.1 Hz, 3H); MS m/z (relative
intensity) 397 (14, M+), 105 (100); HRMS calcd for C24H28
ClNO2 (M+) 397.1809, found 397.1810. Anal. Calcd for C24H28
-
-
ClNO2: C, 72.44; H, 7.09; N, 3.52. Found: C, 72.22; H, 7.21;
N, 3.49.
1
cm-1; H NMR (CDCl3) δ 7.36-7.27 (m, 5H), 4.28 (d, J ) 4.2
cis-N-Ben zoyl-3-(4-ch lor op h en yl)-2-(1-oxon on yl)a zir i-
d in e (cis-4bh ): white powder; mp 104-105 °C; IR (KBr) 1719,
Hz, trans isomer), 4.13 (d, J ) 8.1 Hz, cis isomer), 3.74 (d, J
) 8.1 Hz, cis isomer), 3.60 (d, J ) 4.2 Hz, trans isomer), 3.22
(s, cis isomer), 3.13 (s, trans isomer), 2.71 (t, J ) 7.3 Hz, trans
isomer), 2.24 (dt, J ) 17.2, 7.4 Hz, cis isomer), 2.17 (dt, J )
17.2, 7.4 Hz, cis isomer), 1.78-0.80 (m, 15H). Anal. Calcd for
1
1689, 1318, 707 cm-1; H NMR (CDCl3) δ 8.04 (br d, J ) 8.6
Hz, 2H), 7.62-7.26 (m, 7H), 3.99 (d, J ) 6.8 Hz, 1H), 3.73 (d,
J ) 6.8 Hz, 1H), 2.36 (dt, J ) 16.8, 6.8 Hz, 1H), 2.24 (dt, J )
16.8, 6.8 Hz, 1H), 1.50-0.90 (m, 12H), 0.87 (t, J ) 7.1 Hz,
3H); MS m/z (relative intensity) 397 (8, M+), 292 (10), 105
(100); HRMS calcd for C24H28ClNO2 (M+) 397.1809, found
397.1832.
C
18H27NO3S: C, 64.06; H, 8.06; N, 4.15. Found: C, 64.19; H,
8.21; N, 4.07. cis-4be: colorless plates; mp 71-73 °C (recrys-
tr a n s-N-Ca r bom eth oxy-2-(2,2-d im eth yl-1-oxop r op yl)-
3-p h en yla zir id in e (tr a n s-4cf): colorless plates; mp 110-
112 °C (recrystallized from dichloromethane-hexane); IR
(26) Palladium-catalyzed reactions of N-(arenesulfonyl)-3-alkyl-2-
vinylaziridines reveal that 2,3-cis-ariridines are more stable than the
trans isomers. See: Ibuka, T.; Mimura, N.; Aoyama, H.; Akaji, M.;
Ohno, H.; Miwa, Y.; Taga, T.; Nakai, K.; Tamamura, H.; Fujii, N.;
Yamamoto, Y. J . Org. Chem. 1997, 62, 999.
1
(KBr) 1723, 1308, 1202, 1179, 1082 cm-1; H NMR (CDCl3) δ
7.34 (br s, 5H), 3.78 (s, 3H), 3.63 (d, J ) 2.4 Hz, 1H), 3.52 (d,

Stereoselective Synthesis of 2-Acylaziridines
J . Org. Chem., Vol. 64, No. 9, 1999 3187
J ) 2.4 Hz, 1H), 1.23 (s, 9H); MS m/z (relative intensity) 261
(100, M+), 246 (30), 202 (16); HRMS calcd for C15H19NO3 (M+)
261.1365, found 261.1358. Anal. Calcd for C15H19NO3: C,
68.94; H, 7.33; N, 5.36. Found: C, 68.72; H, 7.32; N, 5.39.
cis-N-Ca r b om et h oxy-2-(2,2-d im et h yl-1-oxop r op yl)-3-
p h en yla zir id in e (cis-4cf): colorless oil; IR (CHCl3) 1725,
tr a n s-5-(2,2-Dim eth yl-1-oxop r op yl)-2,4-d ip h en yl-2-ox-
a zolin e (tr a n s-5cg): colorless plates; mp 122-123 °C (re-
crystallized from dichloromethane-hexane); IR (KBr) 1708,
1
1655, 1061, 700 cm-1; H NMR (CDCl3) δ 8.06 (br d, J ) 7.4
Hz, 2H), 7.60-7.25 (m, 8H), 5.41 (d, J ) 6.8 Hz, 1H), 5.16 (d,
J ) 6.8 Hz, 1H), 1.24 (s, 9H); MS (CI, isobutene) m/z (relative
intensity) 308 (100, M+ + 1), 250 (60).
1
1600, 1270 cm-1; H NMR (CDCl3) δ 7.40-7.26 (m, 5H), 3.95
(d, J ) 7.0 Hz, 1H), 3.90 (d, J ) 7.0 Hz, 1H), 3.79 (s, 3H), 0.99
(s, 9H); MS m/z (relative intensity) 261 (100, M+), 246 (55),
202 (26); HRMS calcd for C15H19NO3 (M+) 261.1365, found
261.1355.
tr a n s-4-(4-Ch lor oph en yl)-5-(2,2-dim eth yl-1-oxopr opyl)-
2-p h en yl-2-oxa zolin e (tr a n s-5ch ): colorless oil; IR (CHCl3)
1710, 1645, 1060 cm-1; 1H NMR (CDCl3) δ 8.05 (br d, J ) 7.4
Hz, 2H), 7.60-7.22 (m, 7H), 5.41 (d, J ) 7.1 Hz, 1H), 5.07 (d,
J ) 7.1 Hz, 1H), 1.24 (s, 9H); MS (CI, isobutene) m/z (relative
intensity) 342 (100, M+ + 1), 284 (45).
Met h yl N-(1-E t h oxy-1-p h en ylm et h yl)ca r ba m a t e (6f):
colorless needles; mp 60-61 °C (recrystallized from dichlo-
romethane-hexane); IR (KBr) 1703, 1543, 1263 cm-1; 1H NMR
(CDCl3) δ 7.50-7.27 (m, 5H), 5.97 (br d, J ) 10.0 Hz, 1H),
5.36 (br d, J ) 10.0 Hz, 1H), 3.87-3.46 (m, 2H), 3.73 (s, 3H),
1.27 (t, J ) 7.1 Hz, 3H).
tr a n s-N-Ben zoyl-2-(2,2-d im eth yl-1-oxop r op yl)-3-p h en -
yla zir id in e (tr a n s-4cg): colorless needles; mp 123-124 °C
(recrystallized from dichloromethane-hexane); IR (KBr) 1701,
1
1681, 1325, 719 cm-1; H NMR (CDCl3) δ 7.90 (br d, J ) 8.5
Hz, 2H), 7.57-7.30 (m, 8H), 3.80 (d, J ) 2.2 Hz, 1H), 3.78 (d,
J ) 2.2 Hz, 1H), 1.17 (s, 9H); MS m/z (relative intensity) 307
(39, M+), 202 (41), 105 (100); HRMS calcd for C20H21NO2 (M+)
307.1572, found 307.1580. Anal. Calcd for C20H21NO2: C,
78.15; H, 6.89; N, 4.56. Found: C, 78.20; H, 6.93; N, 4.48.
cis-N-Ben zoyl-2-(2,2-d im eth yl-1-oxop r op yl)-3-p h en yl-
a zir id in e (cis-4cg): colorless needles; mp 129-131 °C (re-
crystallized from dichloromethane-hexane); IR (KBr) 1708,
1684, 1323, 1088, 702 cm-1; 1H NMR (CDCl3) δ 8.06 (br d, J )
8.5 Hz, 2H), 7.60-7.20 (m, 8H), 4.06 (d, J ) 6.8 Hz, 1H), 4.00
(d, J ) 6.8 Hz, 1H), 0.99 (s, 9H); MS m/z (relative intensity)
307 (34, M+), 202 (41), 105 (100); HRMS calcd for C20H21NO2
(M+) 307.1572, found 307.1564.
N-(1-Eth oxy-1-p h en ylm eth yl)ben za m id e (6g): colorless
needles; mp 97-98 °C (recrystallized from dichloromethane-
1
hexane, lit.27 mp 87-88 °C); H NMR (CDCl3) δ 7.81 (br d, J
) 7.4 Hz, 2H), 7.60-7.25 (m, 8H), 6.65 (br d, J ) 9.4 Hz, 1H),
6.47 (d, J ) 9.4 Hz, 1H), 3.86 (dq, J ) 9.5, 7.1 Hz, 1H), 3.73
(dq, J ) 9.5, 7.1 Hz, 1H), 1.31 (t, J ) 7.1 Hz, 3H).
N -[1-(4-Ch lor op h e n yl)-1-e t h oxym e t h yl]b e n za m id e
(6h ): white powder; IR (KBr) 1641, 1520, 1090 cm-1; 1H NMR
(CDCl3) δ 7.81 (br d, J ) 7.5 Hz, 2H), 7.60-7.26 (m, 7H), 6.60
(br d, J ) 9.4 Hz, 1H), 6.47 (d, J ) 9.4 Hz, 1H), 3.86 (dq, J )
9.6, 7.1 Hz, 1H), 3.71 (dq, J ) 9.6, 7.1 Hz, 1H), 1.30 (t, J ) 7.1
Hz, 3H).
tr a n s-N-Ben zoyl-3-(4-ch lor op h en yl)-2-(2,2-d im eth yl-1-
oxop r op yl)a zir id in e (tr a n s-4ch ): colorless needles; mp
141-143 °C (recrystallized from dichloromethane-hexane); IR
1
(KBr) 1699, 1683, 1324, 1086 cm-1; H NMR (CDCl3) δ 7.88
(E)-10-Eicosen e-9,12-d ion e ((E)-7): colorless crystals; mp
68-70 °C (recrystallized from methanol-dichloromethane); IR
(br d, J ) 8.5 Hz, 2H), 7.55-7.32 (m, 7H), 3.76 (d, J ) 2.4 Hz,
1H), 3.74 (d, J ) 2.4 Hz, 1H), 1.16 (s, 9H); MS m/z (relative
intensity) 341 (16, M+), 236 (14), 105 (100); HRMS calcd for
1
(CHCl3) 1680, 1250, 1175, 980 cm-1; H NMR (CDCl3) δ 6.87
(s, 2H), 2.64 (t, J ) 7.3 Hz, 4H), 1.72-1.50 (m, 4H), 1.41-1.18
(m, 20H), 0.88 (t, J ) 6.8 Hz, 6H); MS m/z (relative intensity)
308 (13, M+), 237 (28), 167 (100); HRMS calcd for C20H36O2
(M+) 308.2715, found 308.2692.
C
C
20H20ClNO2 (M+) 341.1183, found 341.1208. Anal. Calcd for
20H20ClNO2: C, 70.27; H, 5.90; N, 4.10. Found: C, 70.03; H,
5.97; N, 3.99.
cis-N-Ben zoyl-3-(4-ch lor op h en yl)-2-(2,2-d im eth yl-1-ox-
op r op yl)a zir id in e (cis-4ch ): white powder; mp 110-111 °C;
(Z)-10-Eicosen e-9,12-d ion e ((Z)-7): colorless crystals; IR
(CHCl3) 1690, 1600, 1390 cm-1 1H NMR (CDCl3) δ 6.30 (s,
;
1
IR (CHCl3) 1705, 1675, 1290, 1090 cm-1; H NMR (CDCl3) δ
2H), 2.53 (t, J ) 7.3 Hz, 4H), 1.71-1.49 (m, 4H), 1.40-1.12
(m, 20H), 0.88 (t, J ) 6.8 Hz, 6H); MS m/z (relative intensity)
308 (1, M+), 237 (27), 167 (50), 97 (100); HRMS calcd for
8.02 (br d, J ) 8.6 Hz, 2H), 7.61-7.28 (m, 7H), 4.04 (d, J )
6.8 Hz, 1H), 3.98 (d, J ) 6.8 Hz, 1H), 1.01 (s, 9H); MS m/z
(relative intensity) 341 (16, M+), 236 (13), 105 (100); HRMS
calcd for C20H20ClNO2 (M+) 341.1183, found 341.1196.
C
20H36O2 (M+) 308.2715, found 308.2731.
Gen er a l P r oced u r e for Syn th esis of 2-Acyla zir id in es
tr a n s-2,4-Dip h en yl-5-(1-oxon on yl)-2-oxa zolin e (tr a n s-
5bg): colorless oil; IR (CHCl3) 1715, 1650, 1065 cm-1; 1H NMR
(CDCl3) δ 8.10 (br d, J ) 7.4 Hz, 2H), 7.60-7.26 (m, 8H), 5.35
(d, J ) 6.8 Hz, 1H), 4.81 (d, J ) 6.8 Hz, 1H), 2.70 (dt, J )
17.8, 7.6 Hz, 1H), 2.60 (dt, J ) 17.8, 7.6 Hz, 1H), 1.75-1.50
(m, 2H), 1.40-1.12 (m, 10H), 0.87 (t, J ) 7.1 Hz, 3H); 13C NMR
(CDCl3) δ 208.9 (s), 163.8 (s), 141.5 (s), 132.0 (d), 128.9 (d),
128.6 (d), 127.9 (d), 126.9 (s), 126.6 (d), 89.6 (d), 73.8 (d), 38.7
(t), 31.8 (t), 29.4 (t) 29.2 (t), 29.1 (t), 23.0 (t), 22.6 (t), 14.1 (q);
MS m/z (relative intensity) 363 (2, M+), 250 (15), 222 (100);
HRMS calcd for C24H29NO2 (M+) 363.2198, found 363.2220.
tr a n s-4-(4-Ch lor op h en yl)-5-(1-oxon on yl)-2-p h en yl-2-
oxa zolin e (tr a n s-5bh ): colorless oil; IR (CHCl3) 1715, 1645,
4 in THF . A Typ ica l Exa m p le (Ta ble 2, En tr y 18):
N-(Ben zen su lfon yl)-2-(1-oxon on yl)-3-ph en ylazir idin e (4bc).
To a stirred solution of (Z)-(2-acetoxy-1-decenyl)iodonium
bromide (1b: X ) Br, 30 mg, 0.062 mmol) and N-(benzene-
sulfonyl)benzaldimine (3c) (23 mg, 0.094 mmol) in THF (6 mL)
was added a 0.43 M THF solution of EtOLi (0.14 mL, 0.062
mmol) at -78 °C under argon. After being stirred for 2 h at
-78 °C, the reaction mixture was allowed to warm to room
temperature during 8 h, quenched with water, and extracted
with diethyl ether. The organic phase was washed with brine,
dried over anhydrous Na2SO4, and concentrated. The trans:
cis ratio of 2-acylaziridines 4bc was determined to be 31:69
by 1H NMR of the crude reaction mixture. Preparative TLC
(15% ethyl acetate in hexane) of the crude material using silica
gel gave a mixture of trans- and cis-4bc (18.1 mg, 73%).
tr a n s-N-(2,4,6-Tr im eth ylben zen esu lfon yl)-2-(1-oxop r o-
p yl)-3-p h en yla zir id in e (tr a n s-4a d ): colorless needles; mp
74-75 °C (recrystallized from dichloromethane-hexane); IR
(CHCl3) 1720, 1605, 1330, 1165 cm-1; 1H NMR (CDCl3) δ 7.35-
7.19 (m, 5H), 6.92 (s, 2H), 4.31 (d, J ) 4.2 Hz, 1H), 3.72 (d, J
) 4.2 Hz, 1H), 2.58 (s, 6H), 2.36 (s, 3H), 2.30 (s, 3H); MS m/z
(relative intensity) 343 (1, M+), 160 (100), 118 (92); HRMS
calcd for C19H21NO3S (M+) 343.1242, found 343.1243.
1060 cm-1 1H NMR (CDCl3) δ 8.09 (br d, J ) 7.4 Hz, 2H),
;
7.63-7.44 (m, 3H), 7.34 (br d, J ) 8.1 Hz, 2H), 7.28 (br d, J )
8.1 Hz, 2H), 5.34 (d, J ) 6.8 Hz, 1H), 4.74 (d, J ) 6.8 Hz, 1H),
2.72 (dt, J ) 17.8, 7.3 Hz, 1H), 2.59 (dt, J ) 17.8, 7.3 Hz, 1H),
1.75-1.52 (m, 2H), 1.43-1.15 (m, 10H), 0.87 (t, J ) 7.3 Hz,
3H); MS m/z (relative intensity) 397 (9, M+), 284 (20), 256
(100); HRMS calcd for C24H28ClNO2 (M+) 397.1809, found
397.1823.
cis-4-(4-Ch lor op h en yl)-5-(1-oxon on yl)-2-p h en yl-2-ox-
a zolin e (cis-5bh ): colorless oil; IR (CHCl3) 1710, 1645, 1080
1
cm-1; H NMR (CDCl3) δ 8.10 (br d, J ) 7.4 Hz, 2H), 7.63-
cis-N-(2,4,6-Tr im eth ylben zen esu lfon yl)-2-(1-oxopr opyl)-
3-p h en yla zir id in e (cis-4a d ): colorless oil; IR (CHCl3) 1705,
1600, 1330, 1160 cm-1; 1H NMR (CDCl3) δ 7.34-7.15 (m, 5H),
7.45 (m, 3H), 7.28 (br d, J ) 8.3 Hz, 2H), 7.12 (br d, J ) 8.3
Hz, 2H), 5.71 (d, J ) 11.0 Hz, 1H), 5.25 (d, J ) 11.0 Hz, 1H),
2.25 (ddd, J ) 17.8, 7.8, 6.4 Hz, 1H), 1.94 (ddd, J ) 17.8, 7.3,
6.5 Hz, 1H), 1.66-0.80 (m, 15H); MS m/z (relative intensity)
397 (12, M+), 256 (100), 227 (58), 153 (59); HRMS calcd for
(27) Breuer, S. W.; Bernath, T.; Ben-Ishai, D. Tetrahedron 1967,
23, 2869.
C
24H28ClNO2 (M+) 397.1809, found 397.1801.

3188 J . Org. Chem., Vol. 64, No. 9, 1999
Ochiai and Kitagawa
7.02 (s, 2H), 4.20 (d, J ) 7.8 Hz, 1H), 3.63 (d, J ) 7.8 Hz, 1H),
2.79 (s, 6H), 2.34 (s, 3H), 1.74 (s, 3H); MS m/z (relative
intensity) 343 (<1, M+), 160 (100), 118 (87); HRMS calcd for
82); IR (CHCl3) 1700, 1590, 1320, 1150 cm-1; 1H NMR (CDCl3)
δ 7.30-7.12 (4H), 7.01 (s, cis isomer), 6.92 (s, trans isomer),
4.25 (d, J ) 3.9 Hz, trans isomer), 4.13 (d, J ) 7.8 Hz, cis
isomer), 3.67 (d, J ) 3.9 Hz, trans isomer), 3.64 (d, J ) 7.8
Hz, cis isomer), 2.78 (s, cis isomer), 2.60 (t, J ) 7.3 Hz, trans
isomer), 2.58 (s, trans isomer), 2.33 (s, cis isomer), 2.29 (s, trans
isomer), 2.13 (dt, J ) 17.6, 7.1 Hz, cis isomer), 1.98 (dt, J )
17.6, 7.1 Hz, cis isomer), 1.64-0.80 (m, 15H); MS m/z (relative
C
19H21NO3S (M+) 343.1242, found 343.1248.
N-(4-Meth oxyben zen esu lfon yl)-2-(1-oxon on yl)-3-p h en -
yla zir id in e (4bi): colorless crystals (trans:cis ) 27:73);
recrystallized from dichloromethane-hexane; IR (KBr) 1726,
1595, 1340, 1265, 1150 cm-1; 1H NMR (CDCl3) δ 7.97 (br d, J
) 8.8 Hz, cis isomer), 7.75 (br d, J ) 8.8 Hz, trans isomer),
7.37-7.16 (m, 5H), 7.04 (br d, J ) 8.8 Hz, cis isomer), 6.92 (br
d, J ) 8.8 Hz, trans isomer), 4.24 (d, J ) 4.2 Hz, trans isomer),
4.12 (d, J ) 7.8 Hz, cis isomer), 3.89 (s, cis isomer), 3.86 (s,
trans isomer), 3.71 (d, J ) 4.2 Hz, trans isomer), 3.61 (d, J )
7.8 Hz, cis isomer), 2.62 (t, J ) 7.1 Hz, trans isomer), 2.13
(ddd, J ) 17.6, 7.8, 6.6 Hz, cis isomer), 1.92 (dt, J ) 17.6, 7.3
Hz, cis isomer), 1.68-0.78 (m, 15H); MS m/z (relative intensity)
429 (1, M+), 258 (100); HRMS calcd for C24H31NO4S (M+)
429.1974, found 429.1980. Anal. Calcd for C24H31NO4S: C,
67.10; H, 7.27; N, 3.26. Found: C, 66.88; H, 7.20; N, 3.37.
N-(4-Meth ylben zen esu lfon yl)-2-(1-oxon on yl)-3-p h en yl-
a zir id in e (4bj): colorless leaflets (trans:cis ) 32:68); recrys-
tallized from dichloromethane-hexane; IR (KBr) 1724, 1341,
intensity) 475 (<1, M+), 292 (100); HRMS calcd for C26H34
-
-
ClNO3S (M+) 475.1948, found 475.1923. Anal. Calcd for C26H34
ClNO3S: C, 65.60; H, 7.20; N, 2.94. Found: C, 65.44; H, 7.18;
N, 2.83.
N-(Ben zen esu lfon yl)-3-(1-n aph th yl)-2-(1-oxon on yl)azir -
id in e (4bo): colorless oil (trans:cis ) 45:55); IR (CHCl3) 1705,
1330, 1165 cm-1; 1H NMR (CDCl3) δ 8.15-7.21 (m, 12H), 4.81
(d, J ) 4.4 Hz, trans isomer), 4.60 (d, J ) 7.8 Hz, cis isomer),
3.90 (d, J ) 7.8 Hz, cis isomer), 3.82 (d, J ) 4.4 Hz, trans
isomer), 2.85-2.67 (m, trans isomer), 2.17-1.97 (m, cis isomer),
1.84-1.53 (m), 1.42-0.48 (m); MS m/z (relative intensity) 449
(4, M+), 308 (32), 168 (100); HRMS calcd for C27H31NO3S (M+)
449.2025, found 449.2028. Anal. Calcd for C27H31NO3S: C,
72.13; H, 6.95; N, 3.12. Found: C, 71.76; H, 6.93; N, 3.05.
N-(Ben zen esu lfon yl)-3-(2-n aph th yl)-2-(1-oxon on yl)azir -
id in e (4bp ): pale yellow oil (trans:cis ) 31:69); IR (CHCl3)
1710, 1330, 1165 cm-1; 1H NMR (CDCl3) δ 8.09 (br d, J ) 8.5
Hz, cis isomer), 7.86-7.26 (m), 4.45 (d, J ) 4.2 Hz, trans
isomer), 4.33 (d, J ) 7.8 Hz, cis isomer), 3.85 (d, J ) 4.2 Hz,
trans isomer), 3.74 (d, J ) 7.8 Hz, cis isomer), 2.67 (t, J ) 7.2
Hz, trans isomer), 2.12 (dt, J ) 17.5, 7.1 Hz, cis isomer), 1.96
(dt, J ) 17.5, 7.1 Hz, cis isomer), 1.72- -0.69 (m, 15H); MS m/z
(relative intensity) 449 (14, M+), 308 (100), 168 (95); HRMS
calcd for C27H31NO3S (M+) 449.2025, found 449.2017. Anal.
Calcd for C27H31NO3S: C, 72.13; H, 6.95; N, 3.12. Found: C,
71.78; H, 7.08; N, 2.96.
N-(2,4,6-Tr im eth ylben zen esu lfon yl)-3-(2-n a p h th yl)-2-
(1-oxon on yl)a zir id in e (4bq): colorless oil (trans:cis ) 14:
86); IR (CHCl3) 1705, 1600, 1330, 1160 cm-1; 1H NMR (CDCl3)
δ 7.87-7.64 (m, 4H), 7.53-7.40 (m, 2H), 7.35-7.26 (m, 1H),
7.03 (s, cis isomer), 6.89 (s, trans isomer), 4.45 (d, J ) 3.9 Hz,
trans isomer), 4.33 (d, J ) 7.8 Hz, cis isomer), 3.83 (d, J ) 3.9
Hz, trans isomer), 3.72 (d, J ) 7.8 Hz, cis isomer), 2.82 (s, cis
isomer), 2.72-2.64 (m, trans isomer), 2.56 (s, trans isomer),
2.33 (s, cis isomer), 2.28 (s, trans isomer), 2.12 (dt, J ) 17.3,
7.3 Hz, cis isomer), 1.94 (dt, J ) 17.3, 7.3 Hz, cis isomer), 1.70-
0.70 (m, 15H); MS m/z (relative intensity) 491 (3, M+), 308
(100), 168 (79); HRMS calcd for C30H37NO3S (M+) 491.2494,
found 491.2475. Anal. Calcd for C30H37NO3S: C, 73.28; H, 7.58;
N, 2.85. Found: C, 73.01; H, 7.59; N, 2.74.
tr a n s-N-(2,4,6-Tr im et h ylb en zen esu lfon yl)-3-(1,1-d i-
m eth yleth yl)-2-(1-oxon on yl)a zir id in e (tr a n s-4br ): color-
less oil; IR (film) 1723, 1605, 1328, 1160 cm-1; 1H NMR (CDCl3)
δ 6.94 (s, 2H), 3.27 (d, J ) 4.3 Hz, 1H), 3.16 (d, J ) 4.3 Hz,
1H), 2.82-2.67 (m, 2H), 2.69 (s, 6H), 2.30 (s, 3H), 1.77-1.51
(m, 2H), 1.40-1.18 (m, 10H), 0.88 (t, J ) 6.4 Hz, 3H), 0.75 (s,
9H); MS m/z (relative intensity) 421 (12, M+), 238 (35), 182
(100); HRMS calcd for C24H39NO3S (M+) 421.2651, found
421.2619.
1156 cm-1 1H NMR (CDCl3) δ 7.93 (br d, J ) 8.3 Hz, cis
;
isomer), 7.72 (br d, J ) 8.3 Hz, trans isomer), 7.42-7.22 (m,
7H), 4.27 (d, J ) 4.2 Hz, trans isomer), 4.14 (d, J ) 7.8 Hz, cis
isomer), 3.72 (d, J ) 4.2 Hz, trans isomer), 3.67 (d, J ) 7.8
Hz, cis isomer), 2.61 (t, J ) 7.1 Hz, trans isomer), 2.46 (s, cis
isomer), 2.41 (s, trans isomer), 2.12 (dt, J ) 17.6, 7.6 Hz, cis
isomer), 1.92 (dt, J ) 17.6, 7.6 Hz, cis isomer), 1.70-0.73 (m,
15H); MS m/z (relative intensity) 413 (1, M+), 258 (100); HRMS
calcd for C24H31NO3S (M+) 413.2025, found 413.2035. Anal.
Calcd for C24H31NO3S: C, 69.70; H, 7.55; N, 3.39. Found: C,
69.44; H, 7.50; N, 3.23.
N-(4-Ch lor oben zen esu lfon yl)-2-(1-oxon on yl)-3-p h en yl-
a zir id in e (4bk ): colorless crystals (trans:cis ) 35:65); recrys-
tallized from dichloromethane-hexane; IR (CHCl3) 1710, 1580,
1335, 1165 cm-1; 1H NMR (CDCl3) δ 8.00 (br d, J ) 8.6 Hz, cis
isomer), 7.77 (br d, J ) 8.6 Hz, trans isomer), 7.57 (br d, J )
8.6 Hz, cis isomer), 7.44 (br d, J ) 8.6 Hz, trans isomer), 7.38-
7.15 (m, 7H), 4.29 (d, J ) 4.1 Hz, trans isomer), 4.19 (d, J )
8.0 Hz, cis isomer), 3.73 (d, J ) 4.1 Hz, trans isomer), 3.70 (d,
J ) 8.0 Hz, cis isomer), 2.62 (t, J ) 7.1 Hz, trans isomer), 2.12
(dt, J ) 17.3, 7.3 Hz, cis isomer), 1.97 (dt, J ) 17.3, 7.3 Hz, cis
isomer), 1.70-0.75 (m, 15H); MS m/z (relative intensity) 433
(4, M+), 258 (100), 158 (31); HRMS calcd for C23H28ClNO3S
(M+) 433.1478, found 433.1476. Anal. Calcd for C23H28
-
ClNO3S: C, 63.65; H, 6.50; N, 3.23. Found: C, 63.30; H, 6.54;
N, 3.13.
N-(2-Naph th alen esu lfon yl)-2-(1-oxon on yl)-3-ph en ylazir -
id in e (4bl): colorless oil (trans:cis ) 35:65); IR (CHCl3) 1710,
1
1330, 1160 cm-1; H NMR (CDCl3) δ 8.59 (s, cis isomer), 8.31
(s, trans isomer), 8.07-7.54 (m, 6H), 7.35-7.18 (m, 5H), 4.33
(d, J ) 4.2 Hz, trans isomer), 4.24 (d, J ) 8.1 Hz, cis isomer),
3.80 (d, J ) 4.2 Hz, trans isomer), 3.73 (d, J ) 8.1 Hz, cis
isomer), 2.64 (t, J ) 6.8 Hz, trans isomer), 2.12 (dt, J ) 17.5,
6.6 Hz, cis isomer), 1.94 (dt, J ) 17.5, 6.8 Hz, cis isomer), 1.70-
0.76 (m, 15H); MS m/z (relative intensity) 449 (1, M+), 258
(64), 158 (100); HRMS calcd for C27H31NO3S (M+) 449.2025,
found 449.2044. Anal. Calcd for C27H31NO3S: C, 72.13; H, 6.95;
N, 3.12. Found: C, 71.79; H, 7.10; N, 2.90.
cis-N-(2,4,6-Tr im eth ylben zen esu lfon yl)-3-(1,1-d im eth -
yleth yl)-2-(1-oxon on yl)a zir id in e (cis-4br ): colorless oil; IR
1
(film) 1716, 1604, 1329, 1160 cm-1; H NMR (CDCl3) δ 7.00
N-(2,4,6-Tr im eth ylben zen esu lfon yl)-3-(4-m eth ylph en yl)-
2-(1-oxon on yl)a zir id in e (4bm ): colorless oil (trans:cis ) 18:
82); IR (CHCl3) 1705, 1600, 1330, 1160 cm-1; 1H NMR (CDCl3)
δ 7.20-7.04 (4H), 7.00 (s, cis isomer), 6.91 (s, trans isomer),
4.24 (d, J ) 4.2 Hz, trans isomer), 4.14 (d, J ) 7.8 Hz, cis
isomer), 3.74 (d, J ) 4.2 Hz, trans isomer), 3.62 (d, J ) 7.8
Hz, cis isomer), 2.78 (s, cis isomer), 2.64-2.60 (trans isomer),
2.58 (s, trans isomer), 2.32 (s, cis isomer), 2.28 (s, cis isomer),
2.12 (dt, J ) 17.3, 7.6 Hz, cis isomer), 1.94 (dt, J ) 17.3, 7.6
Hz, cis isomer), 1.63-0.78 (m, 15H); MS m/z (relative intensity)
455 (14, M+), 357 (10), 272 (100); HRMS calcd for C27H37NO3S
(M+) 455.2494, found 455.2476. Anal. Calcd for C27H37NO3S:
C, 71.17; H, 8.18; N, 3.07. Found: C, 70.94; H, 8.12; N, 2.87.
N-(2,4,6-Tr im eth ylben zen esu lfon yl)-3-(4-ch lor oph en yl)-
2-(1-oxon on yl)a zir id in e (4bn ): colorless oil (trans:cis ) 18:
(s, 2H), 3.22 (d, J ) 8.0 Hz, 1H), 2.83-2.27 (m, 2H), 2.75 (s,
6H), 2.73 (d, J ) 8.0 Hz, 1H), 2.32 (s, 3H), 1.53-1.06 (m, 12H),
0.88 (t, J ) 6.4 Hz, 3H), 0.79 (s, 9H); MS m/z (relative
intensity) 421 (37, M+), 238 (78), 182 (85), 57 (100); HRMS
calcd for C24H39NO3S (M+) 421.2651, found 421.2615.
N-(2,4,6-Tr im eth ylben zen esu lfon yl)-2-(2,2-d im eth yl-1-
oxop r op yl)-3-(4-m eth ylp h en yl)a zir id in e (4cm ): colorless
oil (trans:cis ) 6:94); IR (CHCl3) 1710, 1600, 1325, 1155 cm-1
;
1H NMR (CDCl3) δ 7.21-7.0 (4H), 6.96 (s, cis isomer), 6.89 (s,
trans isomer), 4.33 (d, J ) 4.4 Hz, trans isomer), 4.18 (d, J )
7.6 Hz, cis isomer), 4.05 (d, J ) 7.6 Hz, cis isomer), 3.97 (d, J
) 4.4 Hz, trans isomer), 2.78 (s, cis isomer), 2.57 (s, trans
isomer), 2.29 (s, cis isomer), 2.28 (s, cis isomer), 1.27 (s, trans
isomer), 0.96 (s, cis isomer); MS m/z (relative intensity) 399

Stereoselective Synthesis of 2-Acylaziridines
J . Org. Chem., Vol. 64, No. 9, 1999 3189
(<1, M+), 216 (100); HRMS calcd for C23H29NO3S (M+) 399.1868,
found 399.1839.
TLC (15% ethyl acetate in hexane) gave a mixture of trans-
and cis-2-acylaziridines 4, which was analyzed by 1H NMR.
The results are reported in Table 3.
N-(2,4,6-Tr im eth ylben zen esu lfon yl)-3-(4-ch lor oph en yl)-
2-(2,2-d im eth yl-1-oxop r op yl)a zir id in e (4cn ): colorless oil
(trans:cis ) 3:97); IR (CHCl3) 1710, 1600, 1325, 1155 cm-1; 1H
NMR (CDCl3) δ 7.30-7.15 (4H), 6.97 (s, cis isomer), 6.91 (s,
trans isomer), 4.36 (d, J ) 3.9 Hz, trans isomer), 4.17 (d, J )
7.6 Hz, cis isomer), 4.05 (d, J ) 7.6 Hz, cis isomer), 3.91 (d, J
) 3.9 Hz, trans isomer), 2.77 (s, cis isomer), 2.57 (s, trans
isomer), 2.30 (s, 3H), 1.27 (s, trans isomer), 0.97 (s, cis isomer);
MS m/z (relative intensity) 419 (<1, M+), 236 (100), 194 (41);
HRMS calcd for C22H26ClNO3S (M+) 419.1322, found 419.1310.
Gen er a l P r oced u r e for th e Com p etition Exp er im en ts.
To a stirred solution of the iodonium bromide 1b (X ) Br, 30
mg, 0.062 mmol) in THF (4 mL) was added a 0.43 M THF
solution of EtOLi (0.14 mL, 0.062 mmol) at -78 °C under
argon, and the mixture was stirred for 5 min. After addition
of a solution of N-(benzenesulfonyl)benzaldimine (3c) (153 mg,
0.623 mmol) and a substituted N-sulfonylbenzaldimine (0.623
mmol) in THF (2 mL), the mixture was stirred for 1 h at -78
°C. The reaction mixture was allowed to warm to room
temperature during 8 h, quenched with water, and extracted
with diethyl ether. The organic phase was washed with brine,
dried over anhydrous Na2SO4, and concentrated. Preparative
Rea ction of 1b-rd w ith N-(Ben zen esu lfon yl)ben za ld i-
m in e (3c). The R-deuterated vinyliodonium bromide 1b-Rd
(X ) Br, >99% D) was prepared from 1-decynyl(phenyl)-
iodonium tetrafluoroborate22 by Michael addition of AcOD
according to literature procedure.4 To a stirred solution of 1b-
Rd (X ) Br, 30 mg, 0.062 mmol) and N-sulfonylimine 3c (23
mg, 0.094 mmol) in THF-DMSO (12:1, 6.5 mL) were added
EtOH (14 mg, 0.31 mmol) and a 0.43 M THF solution of EtOLi
(0.14 mL, 0.062 mmol) at -30 °C under argon. The reaction
was allowed to proceed at -30 °C for 2 h. Preparative TLC
(15% ethyl acetate in hexane) of the crude mixture gave a 55:
45 mixture of trans- and cis-2-acylaziridines 4bc-Rd (84% D)
in 59% yield.
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research on Priority Areas
(A) (No. 09239102) from Ministry of Education, Science,
Sports, and Culture, J apan.
J O982346M