Synthesis of 3-alkylseleno-2-cylcobutenone via [2+2] cycloaddition reaction of alkyneselenolate with diphenylketene

Article abstract of DOI:10.1055/s-2002-25374

3-Alkylseleno-2-cyclobutenones were synthesized by reaction of alkyneselenolate with diphenylketene via [2+2] cycloaddition. The complete structure of the 2-cyclobutenone was determined by X-ray diffraction.

Full text of DOI:10.1055/s-2002-25374

LETTER
805
Synthesis of 3-Alkylseleno-2-cylcobutenone via [2+2] Cycloaddition Reaction
of Alkyneselenolate with Diphenylketene
S
ynthesis of 3-Alkylse
a
leno-2-cylc
m
obutenone oru Koketsu,* Masanori Kanoh, Hideharu Ishihara*
Department of Chemistry, Faculty of Engineering, Gifu University, Gifu, 501-1193 Japan
Fax +81(58)2301893; E-mail: koketsu@cc.gifu-u.ac.jp
Received 27 February 2002
Table Synthesis of 3-Alkylseleno-2,4,4-triphenyl-2-cyclobuten-
one 5
Abstract: 3-Alkylseleno-2-cyclobutenones were synthesized by
reaction of alkyneselenolate with diphenylketene via [2+2] cy-
cloaddition. The complete structure of the 2-cyclobutenone was de-
termined by X-ray diffraction.
Reactant
RX
Product
5a
Yield (%)
4a
4b
4c
4d
4e
4f
CH3I
51
52
56
67
38
55
Key words: [2+2] cycloaddition, 3-alkylseleno-2-cyclobutenone,
alkyneselenolate, ketene, X-ray diffraction
C2H5I
5b
C3H7I
5c
Cyclobutenones have emerged as versatile synthons and
interesting electrocyclic ring reactions1 as well as being
useful for the construction of complex organic com-
pounds in recent years.2 They are also interesting for their
reactivity and have been examined by way of computa-
tional calculations.3
C4H9I
5d
C6H5CH2Br
C6H5CH2CH2Br
5e
5f
We are interested in the synthesis of novel cyclic com-
pounds containing selenium.4 We have reported the syn-
thesis of -selenolactam from alkyneselenolate.5 The use
of alkyneselenolate is one of the most efficient methods
for the synthesis of cyclic compounds containing seleni-
um.6 A review details ketene cycloaddition.7 The synthe-
sis of 3-ethoxy-2-cyclobutenone using ketene has been
often reported,8 while there is no report of the synthesis of
3-alkylseleno-2-cyclobutenone according to our best
knowledge. Herein, we describe a facile preparation of a
series of 3-alkylseleno-2,4,4-triphenyl-2-cyclobutenone
trapping with alkyl halides 4 in 38–67% yields (Table).
Alkyl phenylethynyl selenide 6, which was generated by
the reaction of 3 with 4 directly, was obtained as a byprod-
uct (Scheme 1). At first, structure of 5 could not be deter-
mined only by NMR and mass spectra. Therefore, the
single crystals were prepared and were subjected to X-ray
diffraction for the structure determination. Finally, the ab-
solute structure of 5 was confirmed by studies of IR, MS,
1H, 13C and 77Se NMR spectra, elemental analysis and X-
ray diffraction.10
via [2+2] cycloaddition by the reaction of alkyneselenol- Several attempts to determine the optimal conditions for
ate with diphenylketene.9
improvement of the yield of 5b were carried out. The re-
action for 1 h at room temperature gave 5b in 52% yield.
Longer reaction time and higher temperature failed to im-
prove the yield of 5b.
Diphenylketene 2 has been prepared by dehydrohalogena-
tion of substituted acetyl chloride in the presence of a base
in situ. Lithium alkyneselenolate 3 was added into the re-
action mixture. Finally cyclic compound, 3-alkylseleno- Several 3-alkylseleno-2,4,4-triphenyl-2-cyclobutenones 5
2,4,4-triphenyl-2-cyclobutenone 5, was obtained by the were prepared by using the corresponding alkyl halides 4.
C6H5
O
C6H5
C6H5
Et3N
- HCl
C
C O
C6H5
RX
Cl
C6H5
O
H
4
2
C6H5
RSe
C6H5C CSeR
1
+
C6H5
+
+
n-BuLi
C6H5C CH
C6H5C CSeLi
Se
5
6
3
Scheme 1
Synlett 2002, No. 5, 03 05 2002. Article Identifier:
1437-2096,E;2002,0,05,0805,0807,ftx,en;Y02802ST.pdf.
© Georg Thieme Verlag Stuttgart · New York
ISSN 0936-5214

806
M. Koketsu et al.
LETTER
Longer alkyl group gave higher yield of 5 (Table). In the
case of the Moore cyclization enyne-ketenes, generally,
higher temperature, for example more than 100 °C or re-
fluxing, was used for the preparation of desired prod-
ucts.11 In the present reaction, milder conditions, i.e. room
temperature, gave the best result. Studies by Danheiser
and co-workers demonstrated that dichlorocyclobuten-
ones could be prepared by the addition of dichloroketene
to trialkylsilylacetylenes.12 Among their results, addition
of dichloroketene to methyl (trimethylsilyl)acetylene re-
sulted in the formation of two regioisomeric products in a
ratio of 64:36 (7 and 8 in Figure 1). The reactions of
ethoxy(trimethylsilyl)acetylene and phenyl(trimethylsi-
lyl)acetylene with dichloroketene led exclusively to a sin-
gle cycloadduct like type 7.13
Scheme 2
starting materials. The reaction without alkyl halide gave
only mixtures instead of 3-selenoxocyclobutanone, while
it has been reported that a 1,3-cyclobutanedione could be
easily isolated.8a Because 3-selenoxocyclobutanone was
unstable, the stable product 5, which is the enolate form,
was only obtained when 9 was trapped with haloalkane 4.
From these results the formation of 5, could be explained
by the addition of the nucleophilic site of alkyne 3a to the
most electron deficient site, the carbonyl carbon, of the
ketene 2 presented in Scheme 2. That is, in the case of the
present reaction, the electron of resonance structure 3a at-
tacked only the center carbon of ketene 2 via the [2+2] cy-
cloadduct 9 affording the single product 5 but neither 5
nor a mixture of 5 and 5 . The reaction of lithium alkyne-
selenolate 3 (LiSeCCPh) with acyl chloride (RCOCl)
gave Se-alkynyl selenocarboxylate (RCOSeCCPh) by nu-
cleophilic addition of the selenium of 3 to the carbonyl
carbon of acyl chloride.15 On the other hand, the reaction
of 3 (LiSeCCPh) with alkylidenamine (RCH = NR1) af-
forded -selenolactam by addition of the most nucleo-
philic site of alkyne 3a.5 Furthermore, the reactions of
lithium alkynethiolate (LiSCCPh) and lithium ynolate
(LiOCCPh) with carbonyl compound proceeded by addi-
tion of the most nucleophilic site of alkyne to the carbonyl
carbon of the carbonyl compound.16 The present reaction
obeys the latter. Acetylenes bearing transition metal, silyl,
germyl, arsenyl and phosphoryl substituents could serve
as substrates for the [2+2] cycloaddition with ketene. The
regiochemistry of cycloaddition involving organometallic
acetylene was generally seen with simpler alkynes, but si-
lylalkylacetylenes gave both possible regioisomers
(Figure 1).13,17 The present reaction using alkyneseleno-
late was the former.
Cl
Cl
Ph
Ph
O
O
O
O
Cl
Cl
Ph
Ph
Me
SiMe3
Me3Si
Me RSe
Ph Ph
SeR
7
5
5'
8
Figure 1
In the present reaction, only a single product was ob-
tained. The X-ray diffraction study of the product clearly
showed that the crystals were not 5 but 5 (Figure 2 and
Scheme 2).14 The bond length of C2-C3 is 1.375 Å and in-
dicates a double bond. The sum of the three angles around
each of the C1, C2 and C3 atoms is almost 360.0°, respec-
tively. Therefore, the arrangement of C1, C2, C3 C4, O1,
Se1 and C19 atoms is almost planar.
Though many reviews have devoted exclusively to ketene
cycloaddition,7,18 according to our best knowledge, this is
the first example of the reaction of ketene with alkynesel-
enolate.
Figure 2 ORTEP diagram (50% thermal ellipsoids) of com-
pound 5b.
Acknowledgement
We thank Dr. Dale Swenson, of the University of Iowa, Chemistry
Department X-ray Diffraction Facility, for his assistance in acqui-
ring X-ray crystallographic data.
The reaction of phenylethynyl selenide 6 with diphe-
nylketene 2 provided no products other than recovered
Synlett 2002, No. 5, 805–807 ISSN 0936-5214 © Thieme Stuttgart · New York

LETTER
Synthesis of 3-Alkylseleno-2-cylcobutenone
807
temperature for 1 h. The mixture was extracted with diethyl
ether and washed with saturated NaCl solution. The organic
layer was dried over sodium sulfate and evaporated to
dryness. The residue was purified by flash chromatography
on silica gel with n-hexane–diethyl ether (50:1) to give 0.20
g of 5a (51%) as pale yellow crystals; mp 120.9–122.3 °C;
IR (KBr) 1734 cm–1; 1H NMR (CDCl3) 2.12 (s, 3 H, CH3),
References
(1) (a) Allen, A. D.; Cheng, B.; Fenwick, M. H.; Givehchi, B.;
Henry-Riyad, H.; Nikolaev, V. A.; Shikhova, E. A.;
Tahmassebi, D.; Tidwell, T. T.; Wang, S. J. Org. Chem.
2001, 66, 2611. (b) Zora, M.; Koyuncu, I.; Yucel, B.
Tetrahedron Lett. 2000, 41, 7111. (c) Hergueta, A. R.;
Moore, H. W. J. Org. Chem. 1999, 64, 5979. (d) Wipf, P.;
Hopkins, C. R. J. Org. Chem. 1999, 64, 6881. (e) Ohno,
M.; Yamamoto, Y.; Eguchi, S. Synlett 1998, 1167.
(f) Allen, A. D.; Tidwell, T. T. Can. J. Chem. 1999, 77, 802.
(g) Paquette, L. A.; Hamme, A. T. I. I.; Kuo, L. H.; Doyon,
J.; Kreuzholz, R. J. Am. Chem. Soc. 1997, 119, 1242.
(h) Dillon, J. L.; Gao, Q.; Dillon, E. A.; Adams, N.
Tetrahedron Lett. 1997, 38, 2231.
7.27–7.47 (m, 13 H, Ar), 7.79 (d, J = 7.6 Hz, 2 H, Ar); 13
C
NMR (CDCl3) 7.9, 81.7, 127.1, 127.5, 128.2, 128.5, 128.6,
128.8, 129.8, 138.7, 145.7, 169.2, 185.3; 77Se NMR (CDCl3)
257.8; MS (CI): m/z = 391 [M+ + 1]; Anal. Calcd for
C23H18OSe: C, 70.95; H, 4.66. Found: C, 70.63; H, 4.66%.
3-Ethylseleno-2,4,4-triphenyl-2-cyclobutenone 5b: Pale
yellow crystals; mp 111.4–113.2 °C; IR (KBr) 1741cm–1; 1H
NMR (CDCl3) 1.04 (t, J = 7.6 Hz, 3 H, CH3), 2.86 (q, J =
7.6 Hz, 2 H, CH2), 7.27–7.48 (m, 13 H, Ar), 7.80 (d, J = 7.6
Hz, 2 H, Ar); 13C NMR (CDCl3) 14.7, 22.4, 81.6, 127.2,
127.5, 128.3, 128.5, 128.6, 129.9, 138.8, 145.2, 169.7,
185.4; 77Se NMR (CDCl3) 349.2; MS (CI): m/z = 405 [M+
+ 1]; Anal. Calcd for C24H20OSe: C, 71.46; H, 5.00. found:
C, 71.10; H, 5.01%.
(2) (a) Dudley, G. B.; Takaki, K. S.; Cha, D. D.; Danheiser, R.
L. Org. Lett. 2000, 2, 3407. (b) Zhang, S.; Liebeskind, L. S.
J. Org. Chem. 1999, 64, 4042. (c) MacDougall, J. M.;
Santora, V. J.; Verma, S. K.; Turnbull, P.; Hernandez, C. R.;
Moore, H. W. J. Org. Chem. 1998, 63, 6905.
(3) (a) Ikeda, H.; Kato, T.; Inagaki, S. Chem. Lett. 2001, 270.
(b) Huang, W.; Fang, D.; Temple, K.; Tidwell, T. T. J. Am.
Chem. Soc. 1997, 119, 2832. (c) Niwayama, S.; Kallel, E.
A.; Sheu, C.; Houk, K. N. J. Org. Chem. 1996, 61, 2517.
(4) (a) Koketsu, M.; Nada, F.; Ishihara, H. Synthesis 2002, 195.
(b) Ishihara, H.; Koketsu, M.; Fukuta, Y.; Nada, F. J. Am.
Chem. Soc. 2001, 123, 8408. (c) Koketsu, M.; Takenaka,
Y.; Ishihara, H. Synthesis 2001, 731. (d) Koketsu, M.;
Takenaka, Y.; Hiramatsu, S.; Ishihara, H. Heterocycles
2001, 55, 1181. (e) Koketsu, M.; Hiramatsu, S.; Ishihara, H.
Chem. Lett. 1999, 485. (f) Koketsu, M.; Suzuki, N.;
Ishihara, H. J. Org. Chem. 1999, 64, 6473. (g) Koketsu, M.;
Senda, T.; Yoshimura, K.; Ishihara, H. J. Chem. Soc., Perkin
Trans. 1 1999, 453.
(11) (a) Wang, K. K. Chem. Rev. 1996, 96, 207. (b) Sullivan, R.
W.; Coghlan, V. M.; Munk, S. A.; Reed, M. W.; Moore, H.
W. J. Org. Chem. 1994, 59, 2276. (c) Nakatani, K.; Isoe, S.;
Maekawa, S.; Saito, I. Tetrahedron Lett. 1994, 35, 605.
(d) Liebeskind, L. S.; Foster, B. S. J. Am. Chem. Soc. 1990,
112, 8612. (e) Foland, L. D.; Karlsson, J. O.; Perris, S. T.;
Schwabe, R.; Xu, S. L.; Patil, S.; Moore, H. W. J. Am. Chem.
Soc. 1989, 111, 975.
(12) (a) Dudley, G. B.; Takaki, K. S.; Cha, D. D.; Danheiser, R.
L. Org. Lett. 2000, 2, 3407. (b) Loebach, J. L.; Bennett, D.
M.; Danheiser, R. L. J. Org. Chem. 1998, 63, 8380.
(13) Danheiser, R. L.; Sard, H. Tetrahedron Lett. 1983, 24, 23.
(14) Crystallographic data for the structural analysis have been
deposited with the Cambridge Crystallographic Data Centre
as supplementary publication, CCDC No. 176955 for 5b.
Copies of this information can be obtained, free of charge,
on application to CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK (fax:+44(1233)336033 or e-mail:
(5) Ishihara, H.; Yoshimi, M.; Kato, S. Angew. Chem., Int. Ed.
Engl. 1990, 29, 530.
(6) (a) Koketsu, M.; Kanoh, M.; Itoh, E.; Ishihara, H. J. Org.
Chem. 2001, 66, 4099. (b) Koketsu, M.; Yang, H. O.; Kim,
Y. M.; Ichihashi, M.; Ishihara, H. Org. Lett. 2001, 3, 1705.
(c) Watanabe, S.; Mori, E.; Nagai, H.; Kataoka, T. Synlett
2000, 49. (d) Shimada, K.; Akimoto, S.; Itoh, H.; Nakamura,
H.; Takikawa, Y. Chem. Lett. 1994, 1743.
(7) Hyatt, J.; Raynolds, P. W. In Organic Reactions, Vol. 45;
Joyce, R. M., Ed.; John Wiley & Sons, Inc.: New York,
1994, 159.
(8) (a) Wasserman, H. H.; Piper, J. U.; Dehmlow, E. V. J. Org.
Chem. 1973, 38, 1451. (b) Wasserman, H. H.; Dehmlow, E.
V. Tetraherdon Lett. 1962, 1031. (c) Barton, D. H. R.;
Gardner, J. N.; Petterson, R. C.; Stamm, O. A. J. Chem. Soc.
1962, 2708.
(9) This work was first reported at the 222nd National Meeting
of the American Chemical Society, Chicago, August 26-30,
2001.
(10) Procedure: 3-Methylseleno-2,4,4-triphenyl-2-cyclo-
butenone 5a: Lithium alkyneselenolate 3 (2 equiv),
generated in situ from phenylacetylene (2 equiv), n-BuLi
(2 equiv) and elementary selenium (2 equiv.), was added to
THF solution of diphenylketene 2 which was generated from
diphenylacetyl chloride 1 (1 equiv) and triethylamine (1
equiv) under argon atmosphere. Moreover, methyl iodide 4a
(2 equiv) was added to the mixture and was stirred at room
deposit@ccdc.cam.ac.uk).
(15) Ishihara, H.; Yoshimi, M.; Hara, N.; Ando, H.; Kato, S. Bull.
Chem. Soc. Jpn. 1990, 63, 835.
(16) (a) Kowalski, C. J.; Haque, M. S. J. J. Am. Chem. Soc. 1986,
108, 1325. (b) Kowalski, C. J.; Fields, K. W. J. Am. Chem.
Soc. 1978, 104, 321. (c) Miyaura, N.; Yanagi, T.; Suzuki, A.
Chem. Lett. 1979, 535. (d) Schöllkopf, V. U.; Hoppe, I.
Angew. Chem. 1975, 87, 814.
(17) (a) Zaitseva, G. S.; Livantsova, L. I.; Baukov, Y. I.;
Lutsenko, I. F. Zh. Obshch. Khim. 1984, 54, 1323; Chem.
Abstr. 1984, 101, 171389s. (b) Hong, P.; Sonogashira, K.;
Hagihara, N. J. Organomet. Chem. 1981, 219, 363.
(18) (a) Miller, R.; Claudio, A.; Adel, S. In Ulmann’s
Encyclopedia of Industrial Chemistry, Vol. A15; Elvers, B.;
Hawkins, S.; Schulz, G., Eds.; VCH Verlagasgesellschaft:
Weinheim Germany, 1990, 63. (b) Seikaly, H. R.; Tidwell,
T. T. Tetrahedron 1986, 42, 2587. (c) Ulrich, H.
Cycloaddition Reactions of Heterocummulenes; Academic
Press: New York, 1967. (d) Quadbeck, G. Angew. Chem.
1956, 68, 361.
Synlett 2002, No. 5, 805–807 ISSN 0936-5214 © Thieme Stuttgart · New York