Reactions of acyl chlorides with LiAlHSeH. Preparation of diacyl selenides, diacyl diselenides, selenocarboxylates and cyclic selenoanhydrides

Article abstract of DOI:10.1039/b200147k

Various diacyl selenides, diacyl diselenides and selenocarboxylates were synthesized by reaction of several acyl chlorides with LiAlHSeH. Reaction of diacyl chloride with LiAlHSeH afforded cyclic selenoanhydrides. In the ⁷⁷Se NMR spectra, we fo

Full text of DOI:10.1039/b200147k

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Reactions of acyl chlorides with LiAlHSeH. Preparation of diacyl
selenides, diacyl diselenides, selenocarboxylates and cyclic
selenoanhydrides
1
Mamoru Koketsu,* Futoshi Nada, Sohma Hiramatsu and Hideharu Ishihara*
Department of Chemistry, Faculty of Engineering, Gifu University, Gifu 501-1193, Japan.
E-mail: koketsu@cc.gifu-u.ac.jp; Fax: ϩ81-58-230-1893
Received (in Cambridge, UK) 8th January 2002, Accepted 8th February 2002
First published as an Advance Article on the web 22nd February 2002
Various diacyl selenides, diacyl diselenides and selenocarboxylates were synthesized by reaction of several acyl
chlorides with LiAlHSeH. Reaction of diacyl chloride with LiAlHSeH afforded cyclic selenoanhydrides. In the
77Se NMR spectra, we found that the chemical shifts of the diacyl selenides and the diacyl diselenides could
facilitate their distinction.
Table 1 Synthesis of diacyl selenides 3 and diacyl diselenides 4
Introduction
Some methods for synthesizing diacyl selenides and diacyl
diselenides have been reported.1 These methods, however,
include some disadvantages, such as the use of expensive
reagents, the limited availability of the starting materials, the
difficulty of purification and the tedious number of steps for
preparation. A more convenient method is required to over-
come these disadvantages.
Recently, we have reported that reaction of lithium alumin-
ium hydride with elemental selenium in THF formed LiAlH-
SeH and also generated hydrogen gas quantitatively. We have
reported that the use of the above-obtained LiAlHSeH can
afford a wide range of selenium-containing compounds as a
novel selenating reagent.2 In this paper, we wish to describe the
reaction of some kinds of acyl chloride with LiAlHSeH. We
confirmed that 77Se NMR spectroscopy is a useful method
to distinguish between the diacyl selenides and the diacyl
diselenides.
Yield (%)
R
3
4
C6H5
3a
3b
3c
3d
3e
3f
3g
3h
3i
86
91
96
63
97
97
81
72
41
4a
4b
4c
4d
4e
4f
—
—
—
81
85
84
82
86
75
4-CH3C6H4
4-ClC6H4
4-CH3OC6H4
C6H5CH2
C17H35
C3H7
C2H5
a
a
a
CH3
a Product was generated in a reaction mixture in situ quantitatively.
However, it decomposed in the process of purification by silica gel
column chromatography.
Results and discussion
Diacyl selenides 3 were prepared by a convenient method, as
shown in Scheme 1. The reaction of 2 equiv. of acyl chloride 1
Scheme 2
lower aliphatic diacyl selenides, i.e. methyl, ethyl and propyl,
though the product 4 was apparently confirmed to be quan-
titatively formed in the reaction mixture from the result of
TLC monitoring, 4 could not be isolated due to decomposition
in the process of purification by silica gel column chrom-
atography. Hence the present procedures give the selective
preparation method of diacyl selenides 3 and diacyl diselenides
4, individually, by the control of reaction conditions.
We were now interested in the reaction of the intermediate,
which was obtained from treating acyl chloride 1 with 2, with
electrophile. After treating 1 with 2 in THF solution, the inter-
mediate generated in the reaction mixture was reacted with
alkyl halide 5 yielding Se-alkyl selenocarboxylates 6 in mod-
erate yields (Scheme 3). Diacyl diselenides 4 were obtained
via oxidation of the intermediate, while the intermediate was
readily trapped with electrophile 5 to give 6 in this reaction.
77Se NMR spectroscopy of diacyl selenides and diacyl diselen-
ides is one of the useful methods for structure determination.
However, reports including 77Se NMR chemical shifts have
scarcely appeared in any other paper. Typical spectroscopic
properties of compounds 3 and 4 are summarized in Table 2.
Scheme 1
with LiAlHSeH 2 gave diacyl selenides in good yields (Table 1).
While all the previous methods3 required many steps, the
present method can easily isolate diacyl selenides 3 in a single
step in very high yields. So far it has been relatively difficult to
obtain aliphatic diacyl selenides 3 because of their instability.3c,4
The present reaction gave even lower aliphatic diacyl selenides,
i.e. diacyl selenides bearing methyl, ethyl and propyl groups, in
moderate to good yields. Both aromatic and aliphatic diacyl
selenides 3 were obtained in excellent yields (Table 1).
A similar reaction of acyl chloride 1 with 2 is able to give
diacyl diselenides. After reacting 1 with 2, the oxidation of the
mixture by iodine gave diacyl diselenides 4 in high yields
(Scheme 2). Both aromatic and higher aliphatic diacyl diselen-
ides 4 were obtained in excellent yields (Table 1). In the case of
DOI: 10.1039/b200147k
J. Chem. Soc., Perkin Trans. 1, 2002, 737–740
This journal is © The Royal Society of Chemistry 2002
737

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Table 2 Typical spectroscopic properties of compounds 3 and 4
77Se NMR (δ)
13C NMR (δ)a
3
4
3
4
C6H5 (a)
743.2
740.5
749.4
731.0
818.8
809.8
765.5 38.4
615.0
608.2
621.4
599.8
644.2
618.6
617.9 15.1
188.6
188.1
186.8
186.8
195.3
198.1
190.6 4.8
187.3
186.8
186.0
185.4
193.0
194.2
188.8 3.8
4-CH3C6H4 (b)
4-ClC6H4 (c)
4-CH3OC6H4 (d)
C6H5CH2 (e)
C17H35 (f )
Mean
a Chemical shifts of carbonyl carbon.
distilled from sodium–benzophenone and used immediately.
The 77Se chemical shifts were expressed in ppm deshielded with
respect to neat Me2Se in CDCl3. LiAlHSeH 2 was prepared
according to the previously reported method.2 Briefly, the prep-
aration of LiAlHSeH 2 is as follows: to a solution of selenium
powder (0.80 g, 10.0 mmol) in dry THF (100 mL) was added
lithium aluminium hydride (0.38 g, 10.0 mmol) at 0 ЊC under
an argon atmosphere. The mixture was stirred for 30 min.
The black selenium powder was consumed in less than 10 min.
The reaction mixture became a heterogeneous grayish suspen-
sion. Compound 2 was formed in situ and was then ready for
further reaction.
Scheme 3
It was difficult to distinguish between diacyl selenides 3a–3f
(δ 190.6 4.8) and diacyl diselenides 4a–4f (δ 188.8 3.8) from
the differences of the chemical shifts of C᎐O in the 13C NMR
᎐
spectra. On the other hand, we found the significant differences
in the chemical shifts of selenium between 3a–3f (δ 765.5
38.4) and 4a–4f (δ 617.9 15.1) were clear in the 77Se NMR
spectra (Table 2).
We also investigated the reaction of bis(acyl chlorides) 7 with
LiAlHSeH 2 (Scheme 4). Previously, we reported the prepar-
Dibenzoyl selenide 3a
Benzoyl chloride (0.23 mL, 2.0 mmol) was added to the
solution of LiAlHSeH 2 (1.0 mmol), prepared as described
above. The reaction mixture was stirred at 0 ЊC for 2 h. The
mixture was extracted with diethyl ether and washed with sat-
urated 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 dichloromethane–n-
hexane (1 : 1) to give 3a 0.25 g (86%) as a white powder. Mp:
60.6–61.4 ЊC (lit.,4 61.5–62.3 ЊC); 1H NMR (CDCl3) δ 7.49 (4H,
t, J = 8.0 Hz, Ar), 7.63 (2H, t, J = 8.0 Hz, Ar), 7.95 (4H, d, J =
8.0 Hz, Ar); 13C NMR (CDCl3) δ 128.4, 128.9, 134.4, 138.5,
188.6; 77Se NMR (CDCl3) δ 746.2; IR (KBr) ν 1722, 1669 cmϪ1;
MS (CI): m/z = 291 [Mϩ ϩ 1].
Bis(4-methylbenzoyl) selenide 3b
1
Mp: 90.2–90.8 ЊC (lit.,4 90–91 ЊC); H NMR (CDCl3) δ 2.40
(6H, s, CH3), 7.26 (4H, d, J = 8.2 Hz, Ar), 7.83 (4H, d, J =
8.2 Hz, Ar); 13C NMR (CDCl3) δ 21.7, 128.5, 129.6, 136.0,
145.5, 188.1; 77Se NMR (CDCl3) δ 740.5; IR (KBr) ν 1738, 1690
cmϪ1; MS (CI): m/z = 319 [Mϩ ϩ 1].
Bis(4-chlorobenzoyl) selenide 3c
Scheme 4
Mp: 118.6–120.4 ЊC (lit.,4 118.5–120.0 ЊC); H NMR (CDCl3)
1
δ 7.45 (4H, d, J = 8.8 Hz, Ar), 7.87 (4H, d, J = 8.8 Hz, Ar); 13
C
ation of cyclic selenoanhydrides 8 by the reaction of primary
selenoamides with bis(acyl chlorides) 7.5 The reaction using
LiAlHSeH 2, which is prepared simply by stirring elementary
selenium and lithium aluminium hydride in THF, gave cyclic
selenoanhydrides 8 more easily than the reaction using primary
selenoamide and gave 8 in higher yields.5
NMR (CDCl3) δ 129.3, 129.7, 136.5, 141.1, 186.8; 77Se
NMR (CDCl3) δ 749.4; IR (KBr) ν 1736, 1676 cmϪ1; MS (CI):
m/z = 359 [Mϩ ϩ 1].
Bis(4-methoxybenzoyl) selenide 3d
Mp: 77.8–79.8 ЊC (lit.,4 77.8–80.2 ЊC); 1H NMR (CDCl3) δ 3.87
(6H, s, CH3), 6.94 (4H, d, J = 9.2 Hz, Ar), 7.92 (4H, d, J =
9.2 Hz, Ar); 13C NMR (CDCl3) δ 55.6, 114.1, 131.0, 131.3,
164.6, 186.8; 77Se NMR (CDCl3) δ 731.0; IR (KBr) ν 1736, 1654
cmϪ1; MS (CI): m/z = 351 [Mϩ ϩ 1].
Experimental
General procedure
Melting points were determined by use of a Yanagimoto
micromelting point apparatus and are uncorrected. IR spectra
Bis(phenylacetyl) selenide 3e
were measured on a Perkin–Elmer 1600 spectrometer. H, 13C
1
and 77Se NMR spectra were recorded on a JEOL-JNM-α400
(400 MHz) spectrometer. Mass spectra were obtained on a
Shimadzu 9020-DF mass spectrometer. Tetrahydrofuran was
Mp: 53.0–53.4 ЊC; 1H NMR (CDCl3) δ 3.95 (4H, s, CH2), 7.11–
7.15 (4H, m, Ar), 7.21–7.26 (6H, m, Ar); 13C NMR (CDCl3)
δ 55.2, 127.8, 128.8, 129.8, 131.8, 195.3; 77Se NMR (CDCl3)
738
J. Chem. Soc., Perkin Trans. 1, 2002, 737–740

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δ 818.8; IR (KBr) ν 1760, 1699 cmϪ1; MS (CI): m/z = 319 [Mϩ ϩ
1]; Anal. Calcd for C16H14O2Se: C, 60.58; H, 4.45. Found: C,
60.27; H, 4.58%.
NMR (CDCl3) δ 3.88 (6H, s, CH3), 6.96 (4H, d, J = 8.8 Hz, Ar),
7.99 (4H, d, J = 8.8 Hz, Ar); 13C NMR (CDCl3): δ 55.6, 114.2,
129.4, 130.5, 164.4, 185.4; 77Se NMR (CDCl33): δ 599.8;
IR (KBr) ν 1746, 1703 cmϪ1; MS (CI): m/z = 431 [Mϩ ϩ 1].
Distearoyl selenide 3f
Bis(phenylacetyl) diselenide 4e
Mp: 75.0–75.6 ЊC (lit.,4 75.3–75.8 ЊC); 1H NMR (CDCl3) δ 0.88
(6H, t, J = 6.4 Hz, CH3), 1.26 (56H, s, CH2), 1.56–1.70 (4H, m,
CH2), 2.81 (4H, t, J = 7.2 Hz, CH2); 13C NMR (CDCl3) δ 14.1,
22.7, 24.8, 28.7, 29.2, 29.3, 29.5, 29.7, 31.9, 49.5, 198.1; 77Se
NMR (CDCl3) δ 809.8; IR (neat) ν 1774, 1718 cmϪ1; MS (CI):
m/z = 615 [Mϩ ϩ 1].
Mp: 85.6–87.2 ЊC; 1H NMR (CDCl3): δ 4.00 (4H, s, CH2), 7.25–
7.36 (10H, m, Ar); 13C NMR (CDCl3): δ 52.0, 128.3, 128.9,
130.2, 132.0, 193.0; 77Se NMR (CDCl3): δ 644.2; IR (KBr)
ν 1736, 1724 cmϪ1; MS (CI): m/z = 399 [Mϩ ϩ 1]; Anal. Calcd
for C16H14O2Se2: C, 48.50; H, 3.56. Found: C, 48.55; H, 3.66%.
Dibutyryl selenide 3g
Distearoyl diselenide 4f
1H NMR (CDCl3) δ 0.91 (6H, t, J = 7.4 Hz, CH3), 1.57–1.68
(4H, m, CH2), 2.74 (4H, t, J = 7.4 Hz, CH2); 13C NMR
(CDCl3) δ 13.2, 18.3, 51.2, 197.9; 77Se NMR (CDCl3) δ 811.6;
IR (neat) ν 1771, 1719 cmϪ1; MS (CI): m/z = 223 [Mϩ ϩ 1];
Anal. Calcd for C8H14O2Se: C, 43.45; H, 6.38. Found: C, 43.55;
H, 6.42%.
Mp: 79.8–80.3 ЊC (lit.,4 79.8–80.3 ЊC); 1H NMR (CDCl3): δ 0.88
(6H, t, J = 6.8 Hz, CH3), 1.26 (56H, s, CH2), 1.61–1.75 (4H, m,
CH2), 2.79–2.86 (4H, m, CH2); 13C NMR (CDCl3): δ 14.1, 22.7,
25.5, 28.8, 29.2, 29.3, 29.5, 29.6, 31.9, 46.1, 194.2; 77Se NMR
(CDCl3): δ 618.6; IR (KBr) ν 1732 cmϪ1; MS (CI): m/z = 695
[Mϩ ϩ 1].
Dipropionyl selenide 3h
Se-Methyl 4-methylbenzeneselenocarboxylate 6a
1H NMR (CDCl3) δ 1.18 (6H, t, J = 7.6 Hz, CH3), 2.86 (4H, q,
J = 7.6 Hz, CH2); 13C NMR (CDCl3) δ 8.8, 43.1, 198.5; 77Se
NMR (CDCl3) δ 801.6; IR (neat) ν 1783, 1717 cmϪ1; MS (CI):
m/z = 195 [Mϩ ϩ 1]; Anal. Calcd for C6H10O2Se: C, 37.32;
H, 5.22. Found: C, 37.44; H, 5.22%.
p-Toluoyl chloride 1b (0.15 g, 1.0 mmol) was added to a
solution of 2 (1.0 mmol). The reaction mixture was stirred at
0 ЊC for 0.5 h. Methyl iodide 5a (0.14 mL, 1.0 mmol) was added
to the reaction mixture. The reaction mixture was stirred at 0 ЊC
for 2h. The mixture was extracted with dichloromethane and
washed with saturated sodium carbonate solution. The organic
layer was dried over sodium sulfate and evaporated to dryness.
The residue was purified by chromatography on silica gel to give
Diacetyl selenide 3i
1H NMR (CDCl3) δ 2.53 (6H, s, CH3); 13C NMR (CDCl3)
δ 35.9, 194.7; 77Se NMR (CDCl3) δ 836.1; IR (neat) ν 1773, 1723
cmϪ1; MS (CI): m/z = 167 [Mϩ ϩ 1]; Anal. Calcd for C4H6O2Se:
C, 29.11; H, 3.66. Found: C, 29.12; H, 3.78%.
1
6a 0.08 g (38%). Mp: 55.2–56.0 ЊC; H NMR (CDCl3): δ 2.37
(3H, s, CH3), 2.39 (3H, s, CH3), 7.23 (2H, d, J = 7.6 Hz, Ar),
7.80 (2H, d, J = 7.6 Hz, Ar); 13C NMR (CDCl3): δ 4.9, 21.6,
127.1, 129.3, 136.4, 144.4, 194.2; 77Se NMR (CDCl3): δ 438.0;
IR (KBr) ν 1661, 1681 cmϪ1; MS (CI): m/z = 215 [Mϩ ϩ 1].
Dibenzoyl diselenide 4a
Benzoyl chloride (0.23 mL, 2 mmol) was added to the solution
of 2 (2.0 mmol). The reaction mixture was stirred at 0 ЊC for
30 min. Iodine (0.25 g, 2.0 mmol) and potassium iodide (0.07 g,
0.40 mmol) in THF (10 mL) were added to the reaction
mixture. The reaction mixture was stirred at 0 ЊC for 1.5 h. The
mixture was extracted with dichloromethane and washed with
1% sodium hydrogen sulfite and water. The organic layer
was dried over sodium sulfate and evaporated to dryness. The
residue was purified by chromatography on silica gel with
dichloromethane–n-hexane (1 : 1) to give 4a 0.30 g (81%) as a
yellow powder. Mp: 131.0–133.6 ЊC (lit.,1a 129–130 ЊC; lit.,1b
130–131 ЊC; lit.,4 131–132 ЊC); 1H NMR (CDCl3) δ 7.50 (4H, t,
J = 7.6 Hz, Ar), 7.65 (2H, t, J = 7.6 Hz, Ar), 8.01 (4H, d, J =
7.6 Hz, Ar); 13C NMR (CDCl3): δ 128.1, 129.1, 134.3, 136.7,
187.3; 77Se NMR (CDCl3): δ 615.0; IR (KBr) ν 1740, 1686 cmϪ1;
MS (CI): m/z = 371 [Mϩ ϩ 1].
Se-Benzyl 4-methylbenzeneselenocarboxylate 6b
1H NMR (CDCl3): δ 2.36 (3H, s, CH3), 4.32 (2H, s, CH2), 7.18–
7.22 (3H, m, Ar), 7.25–7.29 (2H, m, Ar), 7.35 (2H, d, J = 7.3 Hz,
Ar), 7.78 (2H, d, J = 8.3 Hz, Ar); 13C NMR (CDCl3): δ 21.6,
28.8, 126.9, 127.3, 128.5, 129.0, 129.4, 136.2, 139.1, 144.6,
193.8; 77Se NMR (CDCl3): δ 595.7; IR (KBr) ν 1661, 1681 cmϪ1;
MS (CI): m/z = 291 [Mϩ ϩ 1], lit.6
Cyclic succinic selenoanhydride 8a
Glutaryl chloride 7a (0.20 g, 1.0 mmol) was added to the
solution of 2 (1.0 mmol). The reaction mixture was stirred at
room temperature for 2 h. The mixture was extracted with
dichloromethane and washed with saturated sodium carbonate
solution. The organic layer was dried over sodium sulfate and
evaporated to dryness. The residue was purified by chrom-
atography on silica gel with dichloromethane–n-hexane (1 : 1)
Bis(4-methylbenzoyl) diselenide 4b
1
to give 8a 0.12 g (66%) as an orange oil. H NMR (CDCl3):
δ 2.91 (4H, s, CH2); 13C NMR (CDCl3): δ 45.0, 204.6; 77Se NMR
(CDCl3): δ 700.2; IR (KBr) ν 1709 cmϪ1; MS (CI): m/z = 165
[Mϩ ϩ 1], lit.5
Mp: 109.6–111.2 ЊC (lit.,1a 110–111 ЊC; lit.,1b,4 111.0–111.5 ЊC);
1H NMR (CDCl3) δ 2.42 (6H, s, CH3), 7.29 (4H, d, J = 8.0 Hz,
Ar), 7.90 (4H, d, J = 8.0 Hz, Ar); 13C NMR (CDCl3): δ 21.8,
128.2, 129.7, 134.1, 145.5, 186.8; 77Se NMR (CDCl3): δ 608.2;
IR (KBr) ν 1743, 1702 cmϪ1; MS (CI): m/z = 399 [Mϩ ϩ 1].
Cyclic glutaric selenoanhydride 8b
1H NMR (CDCl3): δ 2.16 (2H, m, CH2), 2.77 (4H, t, J = 6.0 Hz,
CH2); 13C NMR (CDCl3): δ 19.2, 43.6, 200.7; 77Se NMR
(CDCl3): δ 827.4; IR (KBr) ν 1698 cmϪ1; MS (CI): m/z = 179
[Mϩ ϩ 1], lit.5
Bis(4-chlorobenzoyl) diselenide 4c
Mp: 122.4–123.8 ЊC (lit.,1a,1b,4 122–124 ЊC); H NMR (CDCl3)
1
δ 7.49 (4H, d, J = 8.8 Hz, Ar), 7.94 (4H, d, J = 8.8 Hz, Ar); 13
C
NMR (CDCl3): δ 129.4, 129.5, 134.9, 141.0, 186.0; 77Se NMR
(CDCl3): δ 621.4; IR (KBr) ν 1735, 1699 cmϪ1; MS (CI): m/z =
439 [Mϩ ϩ 1].
Cyclic phthalic selenoanhydride 8c
Mp: 60.1–61.2 ЊC; 7.74–7.79 (2H, m, Ph), 7.93–7.99 (2H, m,
Ph); 13C NMR (CDCl3): δ 123.5, 134.9, 141.6, 193.9; 77Se NMR
(CDCl3): δ 611.6; IR (KBr) ν 1690 cmϪ1; MS (CI): m/z = 213
[Mϩ ϩ 1], lit.5
Bis(4-methoxybenzoyl) diselenide 4d
Mp: 106.0–107.2 ЊC (lit.,1a 105.5–107 ЊC; lit.,1b,4 106–107 ЊC); 1H
J. Chem. Soc., Perkin Trans. 1, 2002, 737–740
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