Imidoylation of acidic hydrocarbonz with selenium and izocyanides: A new synthetic method for preparation of selenoimidates

Full text of DOI:10.1021/jo0001479

5
022
J . Org. Chem. 2000, 65, 5022-5025
Im id oyla tion of Acid ic Hyd r oca r bon s w ith
Selen iu m a n d Isocya n id es: A New
Syn th etic Meth od for P r ep a r a tion of
Selen oim id a tes
up to 20 °C, BuNC was added, and the mixture was
stirred for 1 h. Addition of BuI at 0 °C followed by usual
workup and purification using preparative HPLC gave
the corresponding selenoimidate 2a in 76% yield (eq 1,
run 1 in Table 1).
Shin-ichi Fujiwara,*,† Hajime Maeda,‡,1
‡
†
Takahiro Matsuya, Tsutomu Shin-ike,
‡
,§
Nobuaki Kambe, and Noboru Sonoda*
Department of Chemistry, Osaka Dental University,
Hirakata, Osaka 573-1121, J apan, Department of
Molecular Chemistry, Graduate School of Engineering,
Osaka University, Suita, Osaka 565-0871, J apan, and
Department of Applied Chemistry, Faculty of Engineering,
Kansai University, Suita, Osaka 564-8680, J apan
A series of isocyanides was tested under similar
conditions and the results are summarized in Table 1.
Both aliphatic and aromatic isocyanides afforded the
corresponding selenoimidates in good yields as shown in
runs 2-6. However, benzyl isocyanide (run 7) gave low
yield of the product probably because it has acidic
fujiwara@cc.osaka-dent.ac.jp
Received February 2, 2000
Selenoimidates are potentially useful compounds in
synthetic organic chemistry, for example, as precursors
benzylic hydrogens. Thus, when PhMe CNC was used
2
2
3
of imidoyl radicals and iminoethers. Hitherto known
methods for preparation of selenoimidates are (i) alky-
(run 8), selenoimidate 2h was obtained in 87% yield. A
similar reaction by using sulfur in place of selenium did
not afford the corresponding thioimidate at all.
4
lation of selenoamides with alkyl halides, (ii) reaction
4
b,5
of imidoyl chlorides with selenolate anions,
(iii) reac-
Next, we examined the reaction employing hydrocar-
bons having different carbon skeletons. As shown in
Table 2, 9-cinnamylfluorene (3), 1,2,3,4,5-pentamethyl-
cyclopentadiene (5), 4-methyl-4H-cyclopenta[def]phenan-
threne (7), triphenylmethane (9), and 2-phenylpropio-
nitrile (13) were selenoimidoylated efficiently at the
benzylic or allylic carbons under similar conditions (runs
1-4 and 6). Interestingly, selenoimidoylation of diphenyl-
4-pyridylmethane (11) occurred at the nitrogen atom to
tion of imidates with selenols,4b (iv) reaction of oxime
3
sulfonates with organoaluminum selenolates, (v) reac-
tion of isoselenocyanates with organolithiums, and (vi)
6
reaction of imidoyl radicals with diaryl diselenides.7
We have recently shown that lithiated hydrocarbons
derived from fluorene, triphenylmethane, and related
compounds can be carbonylated with carbon monoxide
and selenium resulting in the formation of lithium
selenocarboxylates, which were trapped with methyl
9
give isoselenourea 12 (run 5). This site selectivity can
8
iodide to give selenol esters. Our continuing interest in
be explained by the fact that the anion charge of lithio-
4-pyridyldiphenylmethane is localized at the nitrogen
atom of the pyridyl ring.10
All selenoimidates listed in Tables 1 and 2 could easily
be isolated and obtained as single stereoisomers. The
Z-configuration for selenoimidates was determined by
NOE experiments for 2a , 2b, and 2h , and confirmed by
X-ray analysis for 10.
developing new synthetic reactions mediated by selenium
led us to apply this principle to the preparation of
selenoimidates by using isocyanides, which have an
isoelectronic structure with carbon monoxide. Described
herein is the synthesis of selenoimidates from hydrocar-
bons having an acidic hydrogen, selenium, and a variety
of isocyanides.
9
-Methyl-9H-fluorene (1) was lithiated with BuLi in
To prove the mechanism of this reaction, the following
control experiments were carried out. First, reaction of
9-methylfluorenyllithium with selenium afforded the
corresponding selenide 158 in 93% yield after trapping
with methyl iodide in the absence of isocyanides (eq 2).
Second, when a mixture of 9-methylfluorenyllithium and
t-BuNC was quenched with BuI, the isocyanide was not
THF/HMPA at -78 °C, and then selenium was added at
the same temperature. After the mixture was warmed
a
†
Osaka Dental University.
Osaka University.
Kansai University.
‡
§
(
1) Present address: Department of Chemistry, College of Engineer-
ing, Osaka Prefecture University, Sakai, Osaka 599-8531, J apan.
2) Bachi, M. D.; Denenmark, D. J . Am. Chem. Soc. 1989, 111,
886-1888.
3) Maruoka, K.; Miyazaki, T.; Ando, M.; Matsumura, Y.; Sakane,
11
incorporated (eq 3). Third, treatment of 9-methylfluo-
(
renyllithium with butyl isoselenocyanate gave selenoimi-
1
date 2a in high yield (eq 4).6
(
S.; Hattori, K.; Yamamoto, H. J . Am. Chem. Soc. 1983, 105, 2831-
These results prompted us to propose the reaction
pathways as shown in Scheme 1. Reaction of fluorenyl-
lithium 17 with selenium affords selenolate 18, which
then reacts with isocyanide to give lithium selenocar-
2
6
843.
(4) (a) Cava, M. P.; Saris, L. E. J . Chem. Soc., Chem. Commun. 1975,
17-618. (b) Meese, C. O.; Walter, W.; Mrotzek, H.; Mirzai, H. Chem.
Ber. 1976, 109, 956-964.
(
5) (a) Detty, M. R.; Wood, G. P. J . Org. Chem. 1980, 45, 80-89. (b)
K o¨ hler, R.; Beyer, L.; Hantschmann, A.; Hoyer, E. Z. Chem. 1990, 30,
02.
6) Maeda, H.; Kambe, N.; Sonoda, N.; Fujiwara, S.; Shin-ike, T.
Tetrahedron 1996, 52, 12165-12176.
7) Yamago, S.; Miyazoe, H.; Goto, R.; Yoshida, J . Tetrahedron Lett.
999, 40, 2347-2350.
8) (a) Maeda, H.; Fujiwara, S.; Shin-ike, T.; Kambe, N.; Sonoda,
1
(9) We reported a convenient one-pot procedure for the synthesis of
isoselenoureas from lithium amides, selenium, isocyanides, and alkyl
halides: Maeda, H.; Matsuya, T.; Kambe, N.; Sonoda, N.; Fujiwara,
S.; Shin-ike T. Tetrahedron 1997, 53, 12159-12166.
(10) (a) Bank, S.; Dorr, R. J . Org. Chem. 1987, 52, 501-510. (b)
Bank, S.; Gernon, M. J . Org. Chem. 1987, 52, 5105-5111.
(11) Periasamy, M. P.; Walborsky, H. M. J . Org. Chem. 1974, 39,
600-604.
(
(
1
(
N. J . Am. Chem. Soc. 1996, 118, 8160-8161. (b) Maeda, H.; Fujiwara,
S.; Shin-ike, T.; Kambe, N.; Sonoda, N. Synthesis 1997, 342-346.
1
0.1021/jo0001479 CCC: $19.00 © 2000 American Chemical Society
Published on Web 07/13/2000

Notes
Ta ble 1. Selen oim id oyla tion of 9-Meth yl-9H-flu or en ea
J . Org. Chem., Vol. 65, No. 16, 2000 5023
Sch em e 1. P la u sible Rea ction P a th w a ys
run
RNC
productb
isolated yield (%)
1
2
3
4
5
6
7
8
n-BuNC
c-C6H11NC
t-BuNC
2a
2b
2c
2d
2e
2f
76
71
87
76
76
70
29
87
c
TMBI
PhNC
XyNC
d
PhCH2NC
PhMe2CNC
2g
2h
a
Conditions: 1 (2.0 mmol), BuLi (2.2 mmol), THF (25 mL),
HMPA (6.0 mmol), -78 °C, 30 min; Se (2.4 mmol), -78 (∼ 20) °C,
3
0 min; RNC (2.2 mmol), 20 °C, 1 h; Bul (4.0 mmol), 0 °C, 30 min.
b
c
All selenoimidates were obtained as single stereoisomers. TMBI
d
)
1,1,3,3-tetramethylbutyl isocyanide. Xy ) 2,6-xylyl.
Ta ble 2. Selen oim id oyla tion of Acid ic Hyd r oca r bon sa
c
c
c
When BuLi or PhLi was employed instead of fluorenyl-
lithium under similar conditions, only BuSeBu or
PhSeBu was obtained, respectively, without any imidoy-
lated products. This may be because high activation
energy is required for the rearrangement process in these
cases where Bu and Ph migrate as a carbanion.
Next, we examined hydrolysis of selenoimidates be-
cause there has been no example of such to date.
Although thioimidates are known to be hydrolyzed giving
amides and thiol esters depending on their structure and/
or pH value of the buffer,14 we found that N-alkylsele-
noimidates 2a -d ,g underwent hydrolysis easily giving
amides 22 in excellent yields by simply passing them
through a silica gel column eluted with n-hexane-ether
c
c
(12) Although it is not yet certain whether 19 can really exist in
the reaction media or whether it is more like a transition state than
an intermediate, isocyanides were known to insert into an S-Li or
O-Li bond intramolecularly. (a) Dondoni, A.; Fantin, G.; Fogagnolo,
M.; Medici, A.; Pedrini, P. Synthesis 1987, 693-696. (b) Bortolini, O.;
Fantin, G.; Fogagnolo, M.; Medici, A.; Pedrini, P. Heterocycles 1990,
a
Conditions: substrate (2.0 mmol), BuLi (2.2 mmol), THF (25
mL), HMPA (6.0 mmol), -78 °C, 30 min; Se (2.4 mmol), -78 (∼
2
0
0) °C, 30 min; isocyanide (2.2 mmol), 20 °C, 1 h; Bul (4.0 mmol),
3
1, 1213-1216. (c) Fantin, G.; Fogagnolo, M.; Medici, A.; Pedrini, P.
b
°C, 30 min. All selenoimidates were obtained as single stere-
oisomers. Xy ) 2,6-xylyl.
Heterocycles 1993, 36, 473-484.
c
(13) Intermolecular insertion of isocyanides into an O-Li bond
seems to be reversible because isocyanides were formed by hydrogen
abstraction from imidates with alkyllithiums. (a) Koga, N.; Koga, G.;
Anselme, J .-P. Tetrahedron Lett. 1970, 3309-3312. (b) Pornet, J .;
Miginiac, M. L. Tetrahedron Lett. 1971, 967-970.
boximidate 20, probably via formal rearrangement of
9.
1
2,13
1
It is still a question whether the rearrangement
(14) Leading references for hydrolysis of thioimidates include the
proceeds intramolecularly or intermolecularly with elimi-
nation of isoselenocyanate. Trapping of 20 with BuI forms
selenoimidate 2. An alternative pathway via generation
of lithio aldimine 21 by the direct reaction of 17 with
isocyanide and subsequent trapping with selenium seems
unlikely from the control experiment shown in eq 3.11
following. (a) Chaturvedi, R. K.; MacMahon, A. E.; Schmir, G. L. J .
Am. Chem. Soc. 1967, 89, 6984-6993. (b) Chaturvedi, R. K.; Schmir,
G. L. J . Am. Chem. Soc. 1969, 91, 737-746. (c) Hall, A. J .; Satchell,
D. P. N. J . Chem. Soc., Perkin Trans. 2 1976, 1274-1278. (d) Hall, A.
J .; Satchell, D. P. N. J . Chem. Soc., Perkin Trans. 2 1976, 1278-1284.
(e) Barton, D. H. R.; Ozbalik, N.; Vacher, B. Tetrahedron 1988, 44,
3501-3512.

5
024 J . Org. Chem., Vol. 65, No. 16, 2000
Notes
Ta ble 3. Hyd r olysis of Selen o- a n d Th ioim id a tes
stirring was continued for 1 h. After BuI (4.2 mmol) was added
to the solution at 0 °C, the mixture was warmed again to 20 °C.
run
imidate
Z
R
product
isolated yield (%)
Aqueous saturated NH
4
Cl solution (50 mL) was added, and the
1
2
3
4
5
6
7
8
9
2a
2b
2c
2d
2g
2e
2f
23a
23b
Se
Se
Se
Se
Se
Se
Se
S
n-Bu
c-C6H11
t-Bu
22a
22b
22c
22d
22g
92
99
95
92
91
0
0
11
0
product was extracted with ether (50 mL), dried over MgSO ,
4
and evaporated to give a yellow residue. Purification by recycling
preparative HPLC afforded Se-bu tyl N-bu tyl-9-m eth yl-9H-
a
1
TMB
flu or en e-9-selen oca r boxim id a te (2a ) as yellow oil. H NMR
PhCH2
Ph
(
270 MHz, CDCl
H), 1.01 (t, J ) 7.2 Hz, 3 H), 1.51 (sext, J ) 7.2 Hz, 2 H), 1.66
s, 3 H), 1.78 (quint, J ) 7.2 Hz, 2 H), 2.19 (t, J ) 7.3 Hz, 2 H),
.62 (t, J ) 7.2 Hz, 2 H), 7.24-7.44 (m, 6 H), 7.77 (d, J ) 7.8
Hz, 2 H). NOE experiment: irradiation at methylene triplet
(NCH ) at δ 3.62 resulted in a 6.0% enhancement of the signal
3
at δ 2.19 (SeCH , δ): 13.39, 14.01,
3
, δ): 0.63 (t, J ) 7.1 Hz, 3 H), 0.86-1.04 (m, 4
b
Xy
(
3
n-Bu
Ph
22a
S
a
TMB ) 1,1,3,3-tetramethylbutyl. b Xy ) 2,6-xylyl.
2
1
3
2
). C NMR (68 MHz, CDCl
0.66, 22.48, 24.39, 26.59, 32.59, 32.90, 56.93, 63.66, 120.12,
23.80, 127.36, 127.80, 141.57, 149.50, 159.68. Anal. Calcd for
29NSe: C, 69.33; H, 7.34; N, 3.52. Found: C, 69.31; H, 7.22;
N, 3.59.
Se-Bu tyl N-ter t-Bu tyl-9-cin n a m yl-9H-flu or en e-9-selen o-
2
1
(
eq 5). The yields of the resulting amides are listed in
23
C H
1
ca r boxim id a te (4). Yellow oil. H NMR (270 MHz, CDCl
.54 (t, J ) 6.8 Hz, 2 H), 0.81-0.87 (m, 4 H), 1.52 (s, 9 H), 1.67
t, J ) 7.3 Hz, 2 H), 2.98 (d, J ) 7.3 Hz, 2 H), 5.75-5.86 (m, 1
H), 5.96 (d, J ) 15.6 Hz, 1 H), 7.01-7.45 (m, 11 H), 7.69 (d, J )
3
, δ):
0
(
7
2
1
1
5
.3 Hz, 2 H). 13C NMR (68 MHz, CDCl
3
) δ: 13.16, 22.68, 26.82,
9.96, 32.33, 44.92, 58.09, 68.87, 119.89, 125.05, 125.86, 126.56,
27.13, 127.37, 127.68, 128.24, 132.39, 138.01, 141.49, 147.96,
50.23. HRMS (EI) Calcd for C31
02.2022.
H36NSe: 502.2013. Found:
Table 3. But this method cannot be applied to selenoimi-
dates possessing an aromatic substituent, probably be-
cause of the difficulty of protonation in the first stage of
hydrolysis (runs 6, 7). Under similar conditions, N-
alkylthioimidate 23a was only partially hydrolyzed to
amide 22a , and N-arylthioimidate 23b was recovered
unchanged (runs 8, 9).
In summary, thermodynamically stable organolithiums
derived from acidic hydrocarbons underwent selenoimi-
doylation with selenium and isocyanides under mild
conditions to yield lithium selenocarboximidates. Trap-
ping of the lithium selenocarboximidates with BuI re-
sulted in the formation of the corresponding selenoimi-
dates. It was also revealed that N-alkylselenoimidates
could be converted to amides in excellent yields simply
by passing them through a silica gel column.
Se-Bu tyl N-(2,6-Dim eth ylp h en yl)-1,2,3,4,5-p en ta m eth yl-
1
cyclop en ta d ien e-1-selen oca r boxim id a te (6). Yellow oil. H
NMR (270 MHz, CDCl , δ): 0.69 (t, J ) 7.3 Hz, 3 H), 1.02 (sext,
3
J ) 7.3 Hz, 2 H), 1.11 (quint, J ) 7.3 Hz, 2 H), 1.31 (s, 3 H),
1
.82 (s, 6 H), 1.89 (s, 6 H), 2.11 (t, J ) 7.3 Hz, 2 H), 2.21 (s, 6
13
H), 6.85 (dd, J ) 8.3, 6.4 Hz, 1 H), 6.95 (d, J ) 7.3 Hz, 2 H).
NMR (68 MHz, CDCl , δ): 10.71, 11.40, 13.29, 18.78, 20.38,
3
C
2
1
2.77, 23.23, 32.18, 69.40, 122.90, 125.52, 127.71, 138.01, 139.08,
47.18, 162.73. Anal. Calcd for C23 33NSe: C, 68.64; H, 8.26;
H
N, 3.48. Found: C, 68.32; H, 8.24; N, 3.50.
Se-Bu tyl N-(2,6-Dim eth ylp h en yl)-4-m eth yl-4H-cyclop en -
ta [d ef]p h en a n th r en e-4-selen oca r boxim id a te (8). Yellow oil.
1
H NMR (270 MHz, CDCl , δ): 0.36 (t, J ) 7.0 Hz, 3 H), 0.54
3
(
)
1
sext, J ) 7.0 Hz, 2 H), 0.60 (quint, J ) 7.0 Hz, 2 H), 1.44 (t, J
7.3 Hz, 2 H), 2.02 (s, 3 H), 2.35 (s, 6 H), 6.91 (t, J ) 7.3 Hz,
H), 7.02 (d, J ) 7.3 Hz, 2 H), 7.65-7.74 (m, 4 H), 7.85-7.89
(m, 4 H). 13C NMR (68 MHz, CDCl , δ): 12.89, 18.54, 22.24,
3
2
1
4.40, 25.35, 31.45, 66.72, 120.58, 123.31, 124.00, 125.51, 125.55,
27.88, 127.98, 128.18, 137.09, 147.12, 148.09, 163.25. HRMS
Exp er im en ta l Section
(CI) Calcd for C29
H30NSe: 472.1544. Found: 472.1529.
THF was distilled from sodium benzophenone ketyl. HMPA
was fractionally distilled and dried over calcium hydride. BuLi
Se-Bu tyl N-(2,6-Dim eth ylp h en yl)tr ip h en ylselen oa cet-
im id a te (10). White solid; mp 88 °C. H NMR (270 MHz, CDCl ,
3
1
(
1.6 M solution in hexane) and Se were used as purchased. MeI
δ): 0.60 (t, J ) 6.8 Hz, 3 H), 0.85-1.02 (m, 4 H), 1.95 (t, J ) 6.8
and BuI were distilled from P . Acidic hydrocarbons were
2
O
5
Hz, 2 H), 2.21 (s, 6 H), 6.88 (t, J ) 5.9 Hz, 1 H), 6.96 (d, J ) 8.4
1
3
purified by distillation or recrystallization prior to use. 1,2,3,4,5-
Pentamethylcyclopentadiene, triphenylmethane, 2-phenylpro-
pionitrile, and diphenyl-4-pyridylmethane were obtained from
commercial sources. 9-Methyl-9H-fluorene and 4-methyl-4H-
cyclopenta[def]phenanthrene were prepared by alkylation (with
MeI) of the corresponding unsubstituted substrates. BuNC,
Hz, 2 H), 7.28-7.33 (m, 9 H), 7.51 (dd, J ) 8.4, 1.8 Hz, 6 H).
NMR (68 MHz, CDCl
72.09, 123.95, 125.52, 126.51, 127.37, 128.07, 131.25, 143.92,
146.86, 164.88. Anal. Calcd for C32 33NSe: C, 75.28; H, 6.51;
C
3
, δ): 13.24, 19.17, 22.50, 26.78, 31.30,
H
N, 2.74. Found: C, 75.08; H, 6.52; N, 2.70.
Se-Bu tyl N′-(2,6-Dim eth ylph en yl)-4-diph en ylm eth yliden e-
1
c-C
and PhCH
6
H
11NC, t-BuNC, 1,1,3,3-tetramethylbutyl isocyanide (TMBI),
NC were used as purchased. Other isocyanides were
4H-a zin e-N-selen oca r ba m id a te (12). Yellow oil. H NMR (400
2
3
MHz, CDCl , δ): 0.85 (t, J ) 7.5 Hz, 3 H), 1.28 (sext, J ) 7.5
1
5
synthesized by the reported procedures. PhNCS was used as
purchased. BuNCSe was prepared according to the literature16
and purified by distillation. Hydrolysis of selenoimidates was
performed on a column (3.6 × 6 cm) using Fuji-Silysia silica gel
WB-300 (100-250 mesh).
Im id oyla tion of Acid ic Hyd r oca r bon s w ith Selen iu m
a n d Isocya n id es: A Typ ica l P r oced u r e. To a THF (25 mL)/
HMPA (1 mL, 6 mmol) solution of 9-methyl-9H-fluorene (1, 2.0
mmol) was added BuLi (1.66 M in hexane, 1.30 mL, 2.2 mmol)
at -78 °C under nitrogen. After 30 min, finely ground selenium
powder (2.4 mmol) was added, and the mixture was warmed to
Hz, 2 H), 1.53 (quint, J ) 7.5 Hz, 2 H), 2.06 (s, 6 H), 2.72 (t, J
) 7.5 Hz, 2 H), 6.16 (d, J ) 8.4 Hz, 2 H), 6.91 (t, J ) 7.6 Hz, 1
1
3
H), 7.00 (d, J ) 7.6 Hz, 2 H), 7.15-7.31 (m, 12 H). C NMR
(100 MHz, CDCl
123.40, 124.06, 126.14, 127.28, 127.74, 127.84, 128.02, 128.22,
3
, δ): 13.39, 18.39, 22.75, 27.57, 32.64, 112.11,
130.24, 142.56, 146.39, 147.08. HRMS (EI) Calcd for C31
Se: 512.1731. Found: 512.1728.
32 2
H N -
Se-Bu tyl N-(2,6-Dim eth ylp h en yl)-2-p h en ylp r op ion itr ile-
1
2-selen oca r boxim id a te (14). Yellow oil. H NMR (270 MHz,
CDCl , δ): 0.64 (t, J ) 7.1 Hz, 3 H), 0.93-1.23 (m, 4 H), 2.10 (s,
3
3 H), 2.10-2.24 (m, 1 H), 2.19 (s, 3 H), 2.20 (s, 3 H), 2.43-2.54
(m, 1 H), 6.92-6.94 (m, 3 H), 7.38-7.48 (m, 3 H), 7.64 (dd, J )
2
3
0 °C. A homogeneous dark-red solution was obtained within
0 min. To the flask was added butyl isocyanide (2.2 mmol), and
7.9, 1.5 Hz, 2 H). 13C NMR (68 MHz, CDCl
, δ): 13.13, 17.97,
3
1
1
8.47, 22.42, 26.19, 28.51, 31.46, 54.87, 120.77, 124.13, 125.22,
25.92, 126.49, 128.02, 128.15, 128.63, 129.10, 137.53, 146.15,
(
(
15) Obrecht, R.; Herrmann, R.; Ugi, I. Synthesis 1985, 400-402.
16) Sonoda, N.; Yamamoto, G.; Tsutsumi, S. Bull. Chem. Soc. J pn.
159.68. HRMS (EI) Calcd for C22
398.1259.
26 2
H N Se: 398.1262. Found:
1
972, 45, 2937-2938.

Notes
J . Org. Chem., Vol. 65, No. 16, 2000 5025
9
-Met h yl-9-m et h ylselen o-9H -flu or en e (15).8a 1H NMR
butyl isothiocyanate (2.20 mmol) was added at 20 °C, and the
mixture was stirred for 1 h. After BuI (4.74 mmol) was added
to the solution at 0 °C, the mixture was warmed again to 20 °C.
(
4
2
270 MHz, CDCl
3
, δ): 1.28 (s, 3 H), 1.87 (s, 3 H), 7.28-7.41 (m,
1
3
H), 7.56-7.70 (m, 4 H). C NMR (68 MHz, CDCl
4.85, 49.02, 119.67, 128.83, 127.47, 127.74, 138.93, 150.14.
-Bu tyl-9-m eth yl-9H-flu or en e (16).17 1H NMR (270 MHz,
CDCl , δ): 0.58-0.70 (m, 5 H), 1.08 (q, J ) 7.3 Hz, 2 H), 1.46 (s,
H), 1.93-2.00 (m, 2 H), 7.25-7.40 (m, 6 H), 7.70 (d, J ) 6.8
3
, δ): 3.56,
4
Aqueous saturated NH Cl solution (50 mL) was added, and the
product was extracted with ether (50 mL), dried over MgSO4,
and evaporated to give a yellow residue. Purification by recycling
preparative HPLC afforded S-bu tyl N-bu tyl-9-m eth yl-9H-
9
3
3
1
1
3
flu or en e-9-th ioca r boxim id a te (23a ) as yellow oil. H NMR
Hz, 2 H). C NMR (68 MHz, CDCl
6.66, 40.32, 50.52, 119.44, 122.35, 126.41, 126.70, 139.70,
51.66.
Hyd r olysis of Selen oim id a tes: A Typ ica l P r oced u r e. Se-
Butyl N-butyl-9-methyl-9H-fluorene-9-selenocarboximidate (2a ,
3
, δ): 13.75, 22.94, 26.37,
(
270 MHz, CDCl
H), 1.01 (t, J ) 7.2 Hz, 3 H), 1.51 (sext, J ) 7.2 Hz, 2 H), 1.65
s, 3 H), 1.78 (quint, J ) 7.2 Hz, 2 H), 2.06 (t, J ) 7.3 Hz, 2 H),
.63 (t, J ) 7.2 Hz, 2 H), 7.24-7.42 (m, 6 H), 7.76 (d, J ) 7.8
3
, δ): 0.58 (t, J ) 6.8 Hz, 3 H), 0.83-0.89 (m, 4
2
1
(
3
1
3
Hz, 2 H). C NMR (68 MHz, CDCl
1.35, 25.15, 31.74, 32.76, 33.16, 54.12, 62.54, 120.13, 123.72,
127.39, 127.74, 141.32, 149.71, 162.52. HRMS (CI) Calcd for
30NS: 352.2099. Found: 352.2107.
3
, δ): 13.37, 14.03, 20.69,
0
.48 mmol) was charged on a silica gel column (3.6 × 6 cm) with
2
n-hexane-ether (1:1, 300 mL) to give N-bu tyl-9-m eth yl-9H-
1
flu or en e-9-ca r boxa m id e (22a ) as colorless oil. H NMR (270
27
C H
MHz, CDCl
Hz, 2 H), 1.22 (quint, J ) 7.2 Hz, 2 H), 1.77 (s, 3 H), 3.02 (q, J
7.2 Hz, 2 H), 5.05 (brs, 1 H), 7.32-7.44 (m, 4 H), 7.59 (d, J )
3
, δ): 0.77 (t, J ) 7.2 Hz, 3 H), 1.07 (sext, J ) 7.2
Ack n ow led gm en t. This work was supported in part
)
6
.8 Hz, 2 H), 7.75 (d, J ) 6.8 Hz, 2 H). 1 C NMR (68 MHz, CDCl
δ): 13.58, 19.74, 23.20, 31.29, 39.42, 58.22, 120.33, 124.09,
27.97, 128.17, 140.12, 148.11, 172.97. HRMS (EI) Calcd for
21NO: 279.1623. Found: 279.1625.
P r ep a r a tion of Th ioim id a tes 23: A Typ ica l P r oced u r e.
To a THF (25 mL)/HMPA (1 mL, 6 mmol) solution of 9-methyl-
3
by a Grant-in-Aid from the Ministry of Education,
Science, Sports and Culture, J apan. Thanks are due to
the Instrumental Analysis Center, Faculty of Engineer-
ing, Osaka University.
3
,
1
19
C H
Su ppor tin g In for m ation Available: Full compound char-
1
13
acterization data and copies of H and C NMR spectra of all
new compounds, and an ORTEP diagram and X-ray structure
data for selenoimidate 10. This material is available free of
charge via the Internet at http://pubs.acs.org.
9
1
H-fluorene (1, 2.03 mmol) was added BuLi (1.64 M in hexane,
.35 mL, 2.21 mmol) at -78 °C under nitrogen. After 30 min,
(17) Solov’yanov, A. A.; Beletskaya, I. P.; Reutov, O. A. Zh. Org.
Khim. 1983, 19, 1822-1835; Chem. Abstr. 1984, 100, 22206 g.
J O0001479