Optical resolution of selenonium imides stabilized by an 8-dimethylamino-1-naphthyl group

Article abstract of DOI:10.1246/bcsj.80.2389

Selenonium imides 1 and 2, stabilized by intramolecular coordination of the amino group of 8-dimethylamino-l-naphthyl substituent to the selenium atom, were synthesized. Optically active selenonium imides were obtained by chromatographic resolution on opt

Full text of DOI:10.1246/bcsj.80.2389

Ó 2007 The Chemical Society of Japan
Bull. Chem. Soc. Jpn. Vol. 80, No. 12, 2389–2394 (2007) 2389
Optical Resolution of Selenonium Imides Stabilized
by an 8-Dimethylamino-1-naphthyl Group
ꢀ
ꢀ
Takahiro Soma, Nobumasa Kamigata, Kazunori Hirabayashi, and Toshio Shimizu
Department of Chemistry, Graduate School of Science and Engineering, Tokyo Metropolitan University,
Minami-ohsawa, Hachioji, Tokyo 192-0397
Received May 21, 2007; E-mail: shimizu-toshio@tmu.ac.jp
Selenonium imides 1 and 2, stabilized by intramolecular coordination of the amino group of 8-dimethylamino-1-
naphthyl substituent to the selenium atom, were synthesized. Optically active selenonium imides were obtained by chro-
matographic resolution on optically active columns and were found to be stable toward racemization both in the solid
state and in solution. Absolute configurations of the optically active selenonium imides were assigned on the basis of
specific rotations and circular dichroism spectra.
Chiral tricoordinate organosulfur compounds have been
NTs
NTf
widely studied and are used for asymmetric synthesis, because
optically active sulfur compounds can be obtained by various
methods.1 Optically active tricoordinate selenium and telluri-
um compounds have been isolated, and their properties and ap-
plicability to asymmetric reactions have been examined.2–15
Some optically active selenonium imides have also been pre-
pared16–18 and used as important intermediates in asymmetric
synthesis.19 The first synthesis of an optically active selenoni-
um imide was accomplished by Krasnov et al. in 1981.16 How-
ever, the specific rotation was very low, and the absolute con-
figuration was not determined. Optically pure diastereomeric
and enantiomeric diaryl selenonium imides have also been pre-
pared,17,18 but no optically active alkyl aryl selenonium imides
have been isolated so far, because they are sensitive to trace
amounts of water in the solvent and/or atmospheric moisture,
even though the aryl group possesses bulky substituents, and
is rapidly hydrolyzed to the corresponding selenoxide and
amine.17
Nakanishi and co-workers have previously reported intra-
molecular coordination between selenium and halogen atoms
at 1,8-positions of naphthalene skeletons.20 Recently, we de-
signed and synthesized stable alkyl aryl and diaryl selenonium
imides possessing an 8-dimethylamino-1-naphthyl group that
facilitates intramolecular coordination of the amino group to
the selenium atom due to the rigid structure, and succeeded
in resolving into their enantiomers. Here, we report the syn-
thesis and optical resolution of selenonium imides 1 and 2
(Chart 1). Their chiroptical properties and absolute configura-
tions are also reported.
*
*
Se
R
Se
R
NMe2
NMe2
1a: R = Me
1b: R = Bn
1c: R = Ph
2a: R = Me
2b: R = Bn
2c: R = Ph
Chart 1.
i
1a, 1c
O
Se
R
NMe2
3a: R = Me
ii
2a-2c
3b
: R = Bn
3c: R = Ph
Scheme 1. i: TsNH2, MS3A, toluene, reflux, 80 h; ii: TfNH2,
Na2SO4, CH2Cl2, rt, 17 h.
respectively, by reacting the corresponding selenoxides 3a–3c
with trifluoromethanesulfonamide in the presence of sodium
sulfate. These selenonium imides were stable in the solid state
and in chloroform solution. In all of the selenonium imides
obtained, two singlets assignable to protons of the two methyl
groups of the amino group were observed on the 1H NMR
spectrum due to coordination of the nitrogen atom to the chiral
selenium atom. These results mean that the selenonium imides
are thermodynamically stable toward hydrolysis due to intra-
molecular coordination of the amino group to the selenium
atom.
Results and Discussion
Preparation of Racemic Selenonium Imides. Selenoni-
um imides 1a and 1c were prepared in 50% and 53% yields,
respectively, by reacting the corresponding selenoxides5m,5n
3a and 3c with p-toluenesulfonamide in refluxing toluene,21
whereas selenonium imide 1b could not be obtained by the
similar reaction (Scheme 1). On the other hand, selenonium
imides 2a–2c were synthesized in 53%, 19%, and 51% yields,
Optical Resolution of Selenonium Imides. Selenonium
imide 1a was subjected to an optically active column
Published on the web December 13, 2007; doi:10.1246/bcsj.80.2389

2390 Bull. Chem. Soc. Jpn. Vol. 80, No. 12 (2007)
Optical Resolution of Selenonium Imides
1a
1c
0
30
60
min
0
30
60
min
Fig. 1. Optical resolution of racemic selenonium imides 1 on an optically active column packed with cellulose carbamate deriva-
tive/silica gel (Daicel Chiralcel OD, 4:6 ꢁ 250 mm2) by means of HPLC on an analytical scale (hexane/ethanol = 95/5).
2a
2b
2c
0
30
60
min
0
30
60
min
0
30
60
min
Fig. 2. Optical resolution of racemic selenonium imides 2 on an optically active column packed with amylose derivative/silica gel
(Daicel Chiralpak AS-H, 4:6 ꢁ 250 mm2) by means of HPLC on an analytical scale (hexane/ethanol = 90/10).
Table 1. Optical Resolution and Specific Rotation of Selenonium Imides 1a and 2a–2c
First-eluted enantiomer
Second-eluted enantiomer
Compound
Ethanol/%c)
½ꢀꢂD (c)d)
ee/%
½ꢀꢂD (c)d)
ee/%
1aa)
2ab)
2bb)
2cb)
5
10
10
10
þ73:0 (0.05)
þ334:0 (0.19)
þ119:0 (0.89)
ꢃ145:4 (0.89)
100
100
100
100
ꢃ46:0 (0.04)
ꢃ336:0 (0.22)
ꢃ118:0 (0.73)
þ147:6 (0.44)
60
100
100
100
a) Optical resolution was carried out by HPLC on an optically active column packed
with cellulose carbamate derivative/silica gel (Daicel Chiralcel OD; 4:6 ꢁ 250 mm2) at
25 ꢄC. b) Optical resolution was carried out by HPLC on an optically active column packed
with amylose derivative/silica gel (Daicel Chiralpak AS-H; 4:6 ꢁ 250 mm2) at 25 ꢄC.
c) Volume percentage of ethanol in hexane as an eluent. d) Specific rotations were mea-
sured in chloroform at 28 ꢄC.
(4:6 ꢁ 250 mm2) packed with cellulose carbamate derivative/
that correspond to the enantiomers on a column packed with
amylose derivative/silica gel (Daicel Chiralpak AS-H) using
HPLC (hexane/ethanol = 90/10) on an analytical scale, as
shown in Fig. 2. In the case of 2a, the first- and second-eluted
enantiomers were obtained in optically pure forms by repeated
resolution, in contrast to selenonium imide 1a. The first-eluted
enantiomer of 2a showed positive specific rotation {(+)-2a: ee
100%; ½ꢀꢂD þ334:0 (c 0.19, CHCl3)}, and the second-eluted
enantiomer showed a negative one {(ꢃ)-2a: ee 100%; ½ꢀꢂD
ꢃ336:0 (c 0.22, CHCl3)}. Selenonium imides 2b and 2c were
also resolved into their corresponding optically pure enantio-
mers under the same conditions. The first-eluted enantiomer
of 2b also showed positive specific rotation. However, in the
case of 2c, the first-eluted enantiomer showed negative specific
rotation. The specific rotations and optical purities of 1a and
2a–2c are summarized in Table 1.
silica gel (Daicel Chiralcel OD) using HPLC (hexane/
ethanol = 95/5). Two peaks corresponding to each enantio-
mer of 1a were observed on the chromatogram, as shown in
Fig. 1. However, selenonium imide 1c could not be resolved
on optically active columns, such as Daicel Chiralcel OD
and Chiralpak AS-H. Repeated resolution of the first fraction
of 1a on a preparative scale gave an optically pure selenonium
imide. The second-eluted enantiomer could not be obtained in
an optically pure form in spite of repeated resolution, perhaps
due to tailing of the first-eluted enantiomer. The optical puri-
ties were determined by HPLC using a chiral column. The
first-eluted enantiomer of 1a showed positive specific rotation
{(+)-1a: ee 100%; ½ꢀꢂD þ73:0 (c 0.05, CHCl3)}, and the
second-eluted enantiomer showed a negative one {(ꢃ)-1a: ee
60%; ½ꢀꢂD ꢃ46:0 (c 0.04, CHCl3)}.
Selenonium imide 2a was well resolved into two peaks
Circular Dichroism Spectra, Absolute Configuration,

T. Soma et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 12 (2007) 2391
2
0
2
0
(+)-1a
(-)-1a
(-)-2a
θ
(+)-2a
-2
-2
200
250
250
250
300
350
400
nm
200
250
300
350
400
nm
2
2
(-)-2b
(-)-2c
0
0
θ
θ
(+)-2b
(+)-2c
-2
-2
200
300
350
400
nm
200
250
300
350
400
nm
3
0
θ
(R)-(+)-3a
-3
200
300
350
400
nm
Fig. 3. Circular dichroism spectra of optically active selenonium imides 1a, 2a–2c, and selenoxide (R)-(+)-3a in cyclohexane.
imide (ꢃ)-1a showed a negative first Cotton effect in the cor-
O
responding region, as shown in Fig. 3. On the other hand, op-
tically active selenonium imides (+)-2a–2c showed negative
first Cotton effects at 313, 316, and 315 nm, respectively.
Selenoxide (R)-(+)-3a showed a negative Cotton effect at
318 nm.5m,5n Therefore, the absolute configuration of seleno-
nium imides (+)-2a–2c was assigned to be R-form and that
of (ꢃ)-2a–2c was S, whereas the absolute configuration of
selenonium imides (+)-1a and (ꢃ)-1a could not be assigned.
The stabilities of optically active selenonium imides toward
racemization were examined. Optically active selenonium
imides (+)-1 and (R)-(+)-2a–2c did not racemize in the solid
state and were stable in chloroform and methanol solutions
without racemization for 5 days. These results show that coor-
dination of the intramolecular amino group to the selenium
atom effectively prevents racemization, since the naphthyl
group facilitates intramolecular coordination due to its rigid
structure.
NMe2
Se
Me
(R)-(+)-3a
Chart 2.
and Stability of Optically Active Selenonium Imides. The
absolute configuration of optically active selenonium imides
1a and 2a–2c could not be determined by X-ray analysis, be-
cause no suitable crystal for X-ray analysis could be obtained.
Therefore, the absolute configurations of selenonium imides
1a and 2a–2c were assigned by comparing specific rotations
and circular dichroism spectra with those of optically active
selenoxide (R)-(+)-3a (Chart 2) having known absolute con-
figuration.5m,5n Optically active selenonium imide (+)-1a
showed a positive first Cotton effect at 318 nm on the circular
dichroism spectrum in cyclohexane, whereas selenonium
Conclusion
Thermodynamically stable asymmetric selenonium imides
possessing the 8-dimethylamino-1-naphthyl group 1a, 1c, and

2392 Bull. Chem. Soc. Jpn. Vol. 80, No. 12 (2007)
Optical Resolution of Selenonium Imides
325, 311, 309, 297, 295, 250, 248, 170, 157; IR (KBr) 3064, 2956,
2a–2c were synthesized. Selenonium imides 1a and 2a–2c
were optically resolved by using HPLC with optically active
columns. The absolute configuration of selenonium imides
(+)-2a–2c was assigned to be R-form and that of (ꢃ)-2a–2c
was S. Optically active selenonium imides (+)-1a and (R)-
(+)-2a–2c were found to be stable toward racemization both
in the solid state and in solution.
1562, 1441, 1366, 1179, 1055, 978, 817, 808, 655, 571, 567 cmꢃ1
;
UV (cyclohexane) ꢂmax 218 (1:5 ꢁ 104), 287 (3:6 ꢁ 103) nm; UV
(chloroform) ꢂmax 225 (1:2 ꢁ 104), 286 (1:1 ꢁ 104) nm; Anal.
Calcd for C25H24N2O2SSe: C, 60.60; H, 4.88; N, 5.65%. Found:
C, 60.80; H, 5.12; N, 5.41%.
Synthesis of Selenonium Imides 2a–2c. A dichloromethane
solution (100 mL) of selenoxide5m,5n (1.0 mmol) and trifluoro-
methanesulfonamide (1.0 mmol) was stirred for 17 h in the pres-
ence of sodium sulfate. The sodium sulfate was filtered off, and
the filtrate was concentrated under reduced pressure. Purification
by gel permeation chromatography gave selenonium imide (2a:
53%, 2b: 19%, 2c: 51%).
Experimental
Toluene was distilled from sodium diphenylketyl before use.
Cyclohexane, dichloromethane, and hexane were distilled from
calcium hydride before use. Ethanol was distilled from sodium
ethoxide before use. Methanol was distilled from sodium meth-
oxide before use. Gel permeation chromatography (GPC) was
performed using a JAI LC-908 liquid chromatograph with two
JAIGEL-1H columns (20 mm ꢁ 600 mm), and the products were
eluted with chloroform. All reactions were carried out under nitro-
gen. 1H, 13C, and 77Se NMR spectra were measured on a JEOL
JNM-LA-500 with Me4Si, Me4Si, and MeSeMe as internal or ex-
ternal standard, respectively. Elemental analysis was performed
by using a Perkin-Elmer 240-C. Melting points were determined
on a Yamato MP-21 melting point apparatus. UV–vis spectra were
measured on a UV-3100PC UV–vis–NIR scanning spectrometer.
IR spectra were measured on a Perkin-Elmer Spectrum GX FT-IR
system. Mass spectra (MS) were determined on a JEOL JMS-
GCmate System. Circular dichroism spectra were measured on a
JASCO J-725 Spectropolarimeter. Specific rotations were mea-
sured on a JASCO DIP-140 Digital polarimeter.
8-Dimethylamino-1-naphthylmethylselenonium Trifluoro-
methanesulfonimide (2a):
White solid; mp 187–188 ꢄC;
1H NMR (500 MHz, CDCl3) ꢁ 2.71 (3H, s), 2.83 (3H, s), 2.97 (3H,
s), 7.60 (1H, d, J ¼ 7:5 Hz), 7.65 (1H, t, J ¼ 8:0 Hz), 7.77 (1H, t,
J ¼ 7:5 Hz), 7.89 (1H, d, J ¼ 8:0 Hz), 8.10 (1H, d, J ¼ 8:0 Hz),
8.82 (1H, d, J ¼ 7:5 Hz); 13C NMR (125 MHz, CDCl3) ꢁ 36.8,
43.4, 49.3, 120.4, 126.5, 127.1, 127.3, 127.4, 127.9, 128.1, 132.6,
135.8, 147.3 (CF3 was not observed); 77Se NMR (95 MHz, CDCl3)
ꢁ 892; MS (EI, 30 eV) m=z 412 (80Se, Mþ), 410 (78Se, Mþ), 264,
262, 250, 248, 235, 233, 168, 155, 125, 91; IR (KBr) 3032, 2920,
1564, 1542, 1362, 1200, 1119, 1064, 941, 880, 866, 645, 571, 561
cmꢃ1; UV (cyclohexane) ꢂmax 217 (1:3 ꢁ 104), 278 (3:5 ꢁ 103)
nm; UV (chloroform) ꢂmax 224 (1:3 ꢁ 104), 276 (1:0 ꢁ 104) nm;
Anal. Calcd for C14H15F3N2O2SSe: C, 40.88; H, 3.68; N, 6.81%.
Found: C, 41.11; H, 4.01; N, 6.21%.
Benzyl-8-dimethylamino-1-naphthylselenonium Trifluoro-
Synthesis of Selenonium Imides 1a and 1c. A toluene solu-
tion (20 mL) of selenoxide5m,5n (1.0 mmol) and p-toluenesulfon-
amide (1.0 mmol) was refluxed for 80 h on a Dean-Stark condens-
er equipped with 3A molecular sieves.21 The solution was concen-
trated under reduced pressure, and purification by gel permeation
chromatography gave selenonium imide (1a: 50%, 1c: 53%).
8-Dimethylamino-1-naphthylmethylselenonium p-Toluene-
methanesulfonimide (2b):
White solid; mp 179–180 ꢄC;
1H NMR (500 MHz, CDCl3) ꢁ 2.71 (3H, s), 3.09 (3H, s), 4.10 (1H,
d, J ¼ 11:0 Hz), 4.35 (1H, d, J ¼ 11:0 Hz), 6.91 (2H, d, J ¼ 7:5
Hz), 7.12 (2H, t, J ¼ 7:5 Hz), 7.22 (1H, t, J ¼ 7:5 Hz), 7.56 (1H,
t, J ¼ 7:5 Hz), 7.64 (1H, d, J ¼ 7:5 Hz), 7.65 (1H, d, J ¼ 7:5 Hz),
7.86 (1H, t, J ¼ 7:5 Hz), 8.03 (1H, d, J ¼ 7:5 Hz), 8.44 (1H, d,
J ¼ 7:5 Hz); 13C NMR (125 MHz, CDCl3) ꢁ 43.7, 49.3, 57.1,
119.7, 120.0, 122.3, 126.3, 126.8, 127.1, 127.3, 128.3, 128.5,
129.0, 129.3, 130.6, 132.5, 135.5 (CF3 was not observed);
77Se NMR (95 MHz, CDCl3) ꢁ 842; MS (EI, 30 eV) m=z 488
(80Se, Mþ), 486 (78Se, Mþ), 341, 339, 264, 262, 250, 248, 235,
233, 168, 155, 91; IR (KBr) 3048, 2933, 1551, 1446, 1425, 1245,
1121, 1083, 950, 822, 678, 571 cmꢃ1; UV (cyclohexane) ꢂmax 228
(1:7 ꢁ 104), 291 (3:6 ꢁ 103) nm; UV (chloroform) ꢂmax 224
(1:4 ꢁ 104), 284 (1:0 ꢁ 104) nm; Anal. Calcd for C20H19F3N2O2-
SSe: C, 49.29; H, 3.93; N, 5.75%. Found: C, 49.68; H, 4.23; N,
5.53%.
1
sulfonimide (1a): White solid; mp 154–156 ꢄC; H NMR (500
MHz, CDCl3) ꢁ 2.36 (3H, s), 2.64 (3H, s), 2.66 (3H, s), 2.90 (3H,
s), 7.20 (1H, d, J ¼ 8:0 Hz), 7.51 (2H, d, J ¼ 8:5 Hz), 7.57 (1H, t,
J ¼ 8:0 Hz), 7.64 (1H, t, J ¼ 8:0 Hz), 7.82 (1H, d, J ¼ 8:0 Hz),
7.89 (2H, d, J ¼ 8:5 Hz), 7.99 (1H, d, J ¼ 8:0 Hz), 8.74 (1H, d,
J ¼ 8:0 Hz); 13C NMR (125 MHz, CDCl3) ꢁ 21.3, 35.3, 43.3, 49.3,
119.9, 125.9, 126.7, 126.7, 126.9, 126.9, 128.1, 129.1, 129.8,
131.9, 135.8, 140.6, 144.0, 148.0; 77Se NMR (95 MHz, CDCl3)
ꢁ 892; MS (EI, 30 eV) m=z 434 (80Se, Mþ), 432 (78Se, Mþ), 264,
262, 250, 248, 235, 233, 168, 155, 125, 91; IR (KBr) 3054, 2920,
1565, 1456, 1362, 1255, 1129, 1085, 959, 897, 828, 667, 570, 549
cmꢃ1; UV (cyclohexane) ꢂmax 221 (1:5 ꢁ 104), 290 (3:6 ꢁ 103)
nm; UV (chloroform) ꢂmax 225 (1:2 ꢁ 104), 293 (1:1 ꢁ 104) nm;
Anal. Calcd for C20H22N2O2SSe: C, 55.42; H, 5.12; N, 6.48%.
Found: C, 55.11; H, 5.32; N, 6.21%.
8-Dimethylamino-1-naphthylphenylselenonium Trifluoro-
methanesulfonimide (2c):
White solid; mp 164–166 ꢄC;
1H NMR (500 MHz, CDCl3) ꢁ 2.24 (3H, s), 2.64 (3H, s), 7.14–
7.17 (5H, m), 7.25 (1H, d, J ¼ 7:5 Hz), 7.39 (1H, t, J ¼ 7:5 Hz),
7.70 (1H, d, J ¼ 7:5 Hz), 7.71 (1H, t, J ¼ 7:5 Hz), 7.95 (1H, d,
J ¼ 7:5 Hz), 8.76 (1H, d, J ¼ 7:5 Hz); 13C NMR (125 MHz,
CDCl3) ꢁ 43.6, 49.1, 119.8, 126.3, 126.7, 126.8, 127.1, 128.2,
129.3, 130.1, 130.3, 131.7, 134.0, 135.3, 145.6, 149.2 (CF3 was
not observed); 77Se NMR (95 MHz, CDCl3) ꢁ 884; MS (EI, 30 eV)
m=z 474 (80Se, Mþ), 472 (78Se, Mþ), 327, 325, 311, 309, 297,
295, 250, 248, 170, 157; IR (KBr) 3070, 2980, 1575, 1476, 1367,
1255, 1159, 1061, 959, 867, 848, 560, 541 cmꢃ1; UV (cyclo-
hexane) ꢂmax 219 (1:7 ꢁ 104), 285 (3:2 ꢁ 103) nm; UV (chloro-
form) ꢂmax 221 (1:3 ꢁ 104), 287 (1:1 ꢁ 104) nm; Anal. Calcd for
C19H17F3N2O2SSe: C, 48.21; H, 3.62; N, 5.92%. Found: C, 48.56;
H, 3.94; N, 5.71%.
8-Dimethylamino-1-naphthylphenylselenonium p-Toluene-
1
sulfonimide (1c): White solid; mp 171–173 ꢄC; H NMR (500
MHz, CDCl3) ꢁ 2.14 (3H, s), 2.33 (3H, s), 2.66 (3H, s), 6.97 (2H,
d, J ¼ 7:5 Hz), 7.14 (2H, d, J ¼ 7:5 Hz), 7.19 (2H, t, J ¼ 7:5 Hz),
7.28 (1H, d, J ¼ 7:5 Hz), 7.36 (1H, t, J ¼ 7:5 Hz), 7.52 (1H, t,
J ¼ 7:5 Hz), 7.75 (1H, d, J ¼ 7:5 Hz), 7.81–7.83 (3H, m), 8.08
(1H, d, J ¼ 7:5 Hz), 9.01 (1H, d, J ¼ 7:5 Hz); 13C NMR (125
MHz, CDCl3) ꢁ 21.4, 43.8, 49.1, 120.5, 126.0, 126.1, 126.9,
127.0, 127.1, 127.5, 128.1, 129.0, 129.7, 130.4, 130.8, 132.7,
135.6, 139.2, 140.4, 144.3, 148.4; 77Se NMR (95 MHz, CDCl3) ꢁ
829; MS (EI, 30 eV) m=z 496 (80Se, Mþ), 494 (78Se, Mþ), 327,

T. Soma et al.
Bull. Chem. Soc. Jpn. Vol. 80, No. 12 (2007) 2393
Optical Resolution of Racemic Selenonium Imides by
Means of High-Performance Liquid Chromatography Using
Optically Active Columns. Optical resolution of racemic sele-
nonium imide 1a was performed by HPLC using an optically ac-
tive column packed with cellulose carbamate derivative/silica gel
(Daicel Chiralcel OD, 4:6 ꢁ 250 mm2) with hexane/ethanol (95/
5) as an eluent. Optical resolution of racemic selenonium imides
2a–2c was performed by using an optically active column packed
with amylose derivative/silica gel (Daicel Chiralpak AS-H, 4:6 ꢁ
250 mm2) with hexane/ethanol (90/10) as an eluent. Typically,
2 mg of selenonium imide was charged to the column. A 0.7-mg
sample of the first-eluted selenonium imide was collected, and a
0.7-mg sample of the second-eluted selenonium imide was col-
lected. This process was repeated at 10–15 times. Each of the col-
lected components was subjected to the column again. Finally, ca.
5 mg of optically pure selenonium imides were obtained, except
for (ꢃ)-1a.
fluoromethanesulfonimide {(S)-(À)-2c}: White solid; mp 155–
156 ꢄC; 100% ee; ½ꢀꢂD ꢃ145:4 (c 0.89, CHCl3), ½ꢀꢂ435 ꢃ243:6
(c 0.89, CHCl3), CD (cyclohexane) ꢂmax 316 ([ꢃ] 1:6 ꢁ 104),
228 ([ꢃ] ꢃ1:7 ꢁ 105) nm, 1H NMR, 13C NMR; IR, MS, and UV
spectra were almost the same as those of the racemic one.
Stability toward Racemization of Optically Active Seleno-
nium Imides. The racemization of optically active selenonium
imides (+)-1a and (R)-(+)-2a–2c was examined in 7 mM solution
at 28 ꢄC by means of their specific rotations.
References
1
For books, see: a) P. Metzner, A. Thuillier, Sulfur Reagents
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(+)-8-Dimethylamino-1-naphthylmethylselenonium p-Tolu-
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ee; ½ꢀꢂD þ73:0 (c 0.05, CHCl3), ½ꢀꢂ435 þ110:6 (c 0.05, CHCl3);
CD (cyclohexane) ꢂmax 318 ([ꢃ] 1:4 ꢁ 104), 228 ([ꢃ] ꢃ2:0 ꢁ
105) nm; 1H NMR, 13C NMR, IR, MS, and UV spectra were
almost the same as those of the racemic one.
2
For books, see: a) Organoselenium Chemistry, ed. by T. G.
Back, Oxford University Press, New York, 1999. b) The Chem-
istry of Organic Selenium and Tellurium Compounds, ed. by S.
Patai, Z. Rappoport, Wiley, New York, 1987. c) Organoselenium
Chemistry, ed. by D. Liotta, Wiley, New York, 1987. d) C.
Paulmier, Selenium Reagents and Intermediates in Organic
Synthesis, Pergamon, Oxford, 1986.
(À)-8-Dimethylamino-1-naphthylmethylselenonium p-Tolu-
enesulfonimide {(À)-1a}: White solid; mp 155–160 ꢄC (55%
ee); 60% ee; ½ꢀꢂD ꢃ46:0 (c 0.04, CHCl3), ½ꢀꢂ435 ꢃ65:7 (c 0.04,
CHCl3); CD (cyclohexane) ꢂmax 318 ([ꢃ] ꢃ8:8 ꢁ 103), 228 ([ꢃ]
1:4 ꢁ 105) nm; 1H NMR, 13C NMR, IR, MS, and UV spectra were
almost the same as those of the racemic one.
3
For reviews, see: a) N. Kamigata, T. Shimizu, Rev.
Heteroat. Chem. 1991, 4, 226. b) T. Shimizu, N. Kamigata,
Org. Prep. Proced. Int. 1997, 29, 603. c) T. Shimizu, N.
Kamigata, Rev. Heteroat. Chem. 1998, 18, 11.
(R)-(+)-8-Dimethylamino-1-naphthylmethylselenonium Tri-
fluoromethanesulfonimide {(R)-(+)-2a}: White solid; mp 160–
161 ꢄC; 100% ee; ½ꢀꢂD þ334:0 (c 0.19, CHCl3), ½ꢀꢂ435 þ709:1 (c
0.19, CHCl3); CD (cyclohexane) ꢂmax 313 ([ꢃ] ꢃ1:2 ꢁ 104), 232
4
For reviews, see: a) T. Wirth, Angew. Chem. 2000, 39,
3740. b) T. Wirth, Tetrahedron 1999, 55, 1. c) Y. Nishibayashi,
S. Uemura, Rev. Heteroat. Chem. 1996, 14, 83. d) N. Komatsu,
S. Uemura, Adv. Detailed React. Mech. 1995, 4, 74.
1
([ꢃ] 1:8 ꢁ 105) nm; H NMR, 13C NMR, IR, MS, and UV spectra
were almost the same as those of the racemic one.
5
Selenoxide: a) D. N. Jones, D. Mundy, R. D. Whitehouse,
(S)-(À)-8-Dimethylamino-1-naphthylmethylselenonium Tri-
fluoromethanesulfonimide {(S)-(À)-2a}: White solid; mp 161–
162 ꢄC; 100% ee; ½ꢀꢂD ꢃ336:0 (c 0.22, CHCl3), ½ꢀꢂ435 ꢃ707:4 (c
0.22, CHCl3); CD (cyclohexane) ꢂmax 312 ([ꢃ] 1:3 ꢁ 104), 233
J. Chem. Soc. D 1970, 86. b) N. Zylber, J. Zylber, A. Gaudemer,
J. Chem. Soc., Chem. Commun. 1978, 1084. c) T. G. Back, N.
Ibrahim, D. J. McPhee, J. Org. Chem. 1982, 47, 3283. d) F. A.
Davis, J. M. Billmers, O. D. Stringer, Tetrahedron Lett. 1983,
24, 3191. e) F. A. Davis, O. D. Stringer, J. P. McCauley, Jr., Tetra-
hedron 1985, 41, 4747. f) T. Shimizu, M. Kobayashi, J. Org.
Chem. 1987, 52, 3399. g) T. Shimizu, K. Kikuchi, Y. Ishikawa,
I. Ikemoto, M. Kobayashi, N. Kamigata, J. Chem. Soc., Perkin
Trans. 1 1989, 597. h) F. A. Davis, R. T. Reddy, M. C.
Weismiller, J. Am. Chem. Soc. 1989, 111, 5964. i) F. A. Davis,
R. T. Reddy, J. Org. Chem. 1992, 57, 2599. j) T. Takahashi, N.
Nakano, T. Koizumi, Chem. Lett. 1996, 207. k) T. Shimizu, M.
Enomoto, H. Taka, N. Kamigata, J. Org. Chem. 1999, 64, 8242.
l) T. Soma, T. Shimizu, K. Hirabayashi, N. Kamigata, Heteroat.
Chem. 2007, 18, 301. m) H. Taka, A. Matsumoto, T. Shimizu,
N. Kamigata, Chem. Lett. 2000, 726. n) H. Taka, A. Matsumoto,
T. Shimizu, N. Kamigata, Heteroat. Chem. 2001, 12, 227.
1
([ꢃ] ꢃ1:9 ꢁ 105) nm; H NMR, 13C NMR, IR, MS, and UV spec-
tra were almost the same as those of the racemic one.
(R)-(+)-Benzyl-8-dimethylamino-1-naphthylselenonium Tri-
fluoromethanesulfonimide {(R)-(+)-2b}: White solid; mp 164–
165 ꢄC; 100% ee; ½ꢀꢂD þ119:0 (c 0.89, CHCl3), ½ꢀꢂ
þ258:6
(c 0.89, CHCl3); CD (cyclohexane) ꢂmax 316 ([ꢃ] ꢃ423:52 ꢁ 104),
1
273 ([ꢃ] 1:1 ꢁ 105), 230 ([ꢃ] 1:3 ꢁ 105) nm; H NMR, 13C NMR,
IR, MS, and UV spectra were almost the same as those of the
racemic one.
(S)-(À)-Benzyl-8-dimethylamino-1-naphthylselenonium Tri-
fluoromethanesulfonimide {(S)-(À)-2b}: White solid; mp 164–
165 ꢄC; 100% ee; ½ꢀꢂD ꢃ118:0 (c 0.73, CHCl3), ½ꢀꢂ435 ꢃ259:0 (c
0.73, CHCl3), CD (cyclohexane) ꢂmax 315 ([ꢃ] 2:0 ꢁ 104), 272
1
([ꢃ] ꢃ1:0 ꢁ 105), 230 ([ꢃ] ꢃ1:4 ꢁ 105) nm; H NMR, 13C NMR,
6
Selenonium ylide: a) K. Sakaki, S. Oae, Tetrahedron Lett.
IR, MS, and UV spectra were almost the same as those of the
racemic one.
1976, 17, 3703. b) N. Kamigata, Y. Nakamura, K. Kikuchi, I.
Ikemoto, T. Shimizu, H. Matsuyama, J. Chem. Soc., Perkin Trans.
1 1992, 1721. c) T. Takahashi, N. Kurose, S. Kawanami, A.
Nojiri, Y. Arai, T. Koizumi, M. Shiro, Chem. Lett. 1995, 379.
(R)-(+)-8-Dimethylamino-1-naphthylphenylselenonium Tri-
fluoromethanesulfonimide {(R)-(+)-2c}: White solid; mp 154–
156 ꢄC; 100% ee; ½ꢀꢂD þ147:6 (c 0.44, CHCl3), ½ꢀꢂ435 þ245:5 (c
0.44, CHCl3), CD (cyclohexane) ꢂmax 315 ([ꢃ] ꢃ1:6 ꢁ 104), 230
7
Selenonium salt: a) W. J. Pope, A. Neville, J. Chem. Soc.,
Trans. 1902, 81, 1552. b) F. G. Holliman, F. G. Mann, J. Chem.
Soc. 1945, 37. c) M. Kobayashi, K. Koyabu, T. Shimizu, K.
Umemura, H. Matsuyama, Chem. Lett. 1986, 2117.
1
([ꢃ] 1:5 ꢁ 105) nm; H NMR, 13C NMR, IR, MS, and UV spectra
were almost the same as those of the racemic one.
(S)-(À)-8-Dimethylamino-1-naphthylphenylselenonium Tri-
8
Seleninic acid: a) T. Shimizu, I. Watanabe, N. Kamigata,

2394 Bull. Chem. Soc. Jpn. Vol. 80, No. 12 (2007)
Optical Resolution of Selenonium Imides
Angew. Chem., Int. Ed. 2001, 40, 2460. b) Y. Nakashima, T.
Shimizu, K. Hirabayashi, N. Kamigata, M. Yasuib, M. Nakazatob,
F. Iwasaki, Tetrahedron Lett. 2004, 45, 2301. c) Y. Nakashima, T.
Shimizu, K. Hirabayashi, M. Yasui, M. Nakasato, F. Iwasaki, N.
Kamigata, Bull. Chem. Soc. Jpn. 2005, 78, 710.
Nakashima, T. Shimizu, K. Hirabayashi, M. Yasui, M. Nakasato,
F. Iwasaki, N. Kamigata, Tetrahedron: Asymmetry 2004, 15,
3791.
15 Telluronium imide: a) T. Shimizu, Y. Machida, N.
Kamigata, Eur. J. Org. Chem. 2002, 2265. b) T. Shimizu, Y.
Machida, N. Kamigata, Heteroat. Chem. 2003, 14, 523.
16 V. P. Krasnov, V. I. Naddaka, V. I. Minkin, Zh. Org. Khim.
1981, 17, 445.
17 N. Kamigata, H. Taka, A. Matsuhisa, H. Matsuyama, T.
Shimizu, J. Chem. Soc., Perkin Trans. 1 1994, 2257.
18 a) H. Taka, T. Shimizu, F. Iwasaki, M. Yasui, N.
Kamigata, J. Org. Chem. 1999, 64, 7433. b) T. Shimizu, N. Seki,
H. Taka, N. Kamigata, J. Org. Chem. 1996, 61, 6013.
19 a) Y. Nishibayashi, T. Chiba, K. Ohe, S. Uemura, J. Chem.
Soc., Chem. Commun. 1995, 1243. b) N. Kurose, T. Takahashi, T.
Koizumi, J. Org. Chem. 1996, 61, 2932. c) H. Takada, Y. Miyake,
K. Ohe, S. Uemura, Chem. Commun. 1998, 1557. d) Y. Miyake,
M. Oda, A. Oyamada, H. Takada, K. Ohe, S. Uemura, J. Organo-
met. Chem. 2000, 611, 475.
20 a) S. Hayashi, H. Wada, T. Ueno, W. Nakanishi, J. Org.
Chem. 2006, 71, 5574. b) W. Nakanishi, S. Hayashi, A. Sakaue,
G. Ono, Y. Kawada, J. Am. Chem. Soc. 1998, 120, 3635.
21 S. Tamagaki, S. Oae, K. Sakaki, Tetrahedron Lett. 1975,
16, 649.
9 Seleninamide: Y. Nakashima, T. Shimizu, K. Hirabayashi,
N. Kamigata, J. Org. Chem. 2005, 70, 868.
10 Seleninate ester: Y. Nakashima, T. Shimizu, K.
Hirabayashi, F. Iwasaki, M. Yamasaki, N. Kamigata, J. Org.
Chem. 2005, 70, 5020.
11 Telluroxide: a) T. Shimizu, Y. Yamazaki, H. Taka, N.
Kamigata, J. Am. Chem. Soc. 1997, 119, 5966. b) H. Taka, Y.
Yamazaki, T. Shimizu, N. Kamigata, J. Org. Chem. 2000, 65,
2127.
12 Telluronium ylide: N. Kamigata, A. Matsuhisa, H. Taka,
T. Shimizu, J. Chem. Soc., Perkin Trans. 1 1995, 821.
13 Telluronium salt: a) T. M. Lowry, F. L. Gilbert, J. Chem.
Soc. 1929, 2867. b) F. G. Holliman, F. G. Mann, J. Chem. Soc.
1945, 37. c) T. Shimizu, T. Urakubo, P. Jin, M. Kondo, S.
Kitagawa, N. Kamigata, J. Organomet. Chem. 1997, 539, 171.
d) J. Zhang, S. Saito, T. Koizumi, J. Org. Chem. 1998, 63,
5423.
14 Tellurinic acid: a) Y. Nakashima, T. Shimizu, K.
Hirabayashi, N. Kamigata, Org. Lett. 2004, 6, 2575. b) Y.