Very rapid preparation of SmI2 by sonic treatment of iodoform and metallic samarium

Article abstract of DOI:10.1002/ejoc.200210669

A very rapid preparation of SmI₂ by sonication of a mixture of metallic samarium and iodoform in THF is described. To prove the synthetic applications of the obtained SmI₂ several high-yielding reactions were carried out. Preliminary results for the generation of SmI₂ in THF by sonication from diiodomethane, 1,2-diiodoethane, or iodine are also described. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.

Full text of DOI:10.1002/ejoc.200210669

FULL PAPER
Very Rapid Preparation of SmI by Sonic Treatment of Iodoform and
2
Metallic Samarium
[a]
[a]
[a]
[a]
Jos e´ M. Concell o´ n,* Humberto Rodr ´ı guez-Solla, Eva Bardales, and M o´ nica Huerta
Keywords: Samarium / Sonication / Synthetic methods
A very rapid preparation of SmI
of metallic samarium and iodoform in THF is described. To
prove the synthetic applications of the obtained SmI several
2
by sonication of a mixture
2
for the generation of SmI in THF by sonication from diiodo-
methane, 1,2-diiodoethane, or iodine are also described.
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
2
high-yielding reactions were carried out. Preliminary results Germany, 2003)
Introduction
Results and Discussion
Since the pioneering studies of Kagan[1] samarium diiod-
ide has rapidly become an important reagent in synthetic
organic chemistry because of its versatility in one- and two-
electron-transfer reactions. Several reviews describing its
We first investigated the generation of samarium diiodide
from samarium and iodoform. This synthesis can be carried
out by simple sonication of a mixture of samarium powder
and iodoform in THF. After 5 min, a deep blue solution of
[
2]
applications in organic synthesis have been published.
SmI was obtained (Scheme 1).
2
Samarium diiodide can be prepared in moderate concen-
trations (0.1 ) in THF starting from samarium metal and
diiodomethane, 1,2-diiodoethane or iodine. However, to the
best of our knowledge, no method for the generation of
[3]
SmI has been described starting from iodoform.
2
A general method to prepare samarium diiodide using
sound waves has also not been described.[4] On the other
hand, significant rate enhancements of chemical reactions
have been described when heterogeneous reactions are car-
ried out in the presence of sound waves.[
Scheme 1
5]
This generation of SmI was performed by using com-
2
Moreover, for synthetic purposes, SmI is typically gener- mercial products, without prior purification or activation.
2
ated and utilised in situ. Based on our own experience and An iodine titration was in agreement with quantitative for-
[
6]
[7]
that of others, 1 or 2 h are required for the conventional mation of samarium diiodide.
generation of SmI (from CH I , ICH CH I or I ) and for
In comparison, preparation of SmI
this reason, a most rapid synthesis of SmI would be very treatment of iodoform with samarium (without ultrasonic
by conventional
2
2 2
2
2
2
2
2
desirable.
In this communication we describe a very rapid synthesis case, after 1 h only 48% and after 2 h 65% of SmI
of samarium diiodide in THF by ultrasonic irradiation of titration) was obtained.
a mixture of metallic samarium and iodoform. This is the
To prove the usefulness of the SmI
irradiation), requires 3 h to complete the reaction. In this
(iodine
2
in THF prepared
2
first synthesis of this reagent by this method and several by sonication several transformations were performed: a β-
organic reactions were carried out to prove the reactivity of elimination reaction from ethyl 2-methyl-3-(4-methoxyphe-
[
8]
the SmI thus generated. We also describe the beneficial nyl)-2,3-epoxypropanoate, a reduction reaction of sorbic
2
effects of faster reactions that ultrasonic irradiation has on acid in the presence of D O to the corresponding 2,5-dide-
2
[
9]
the generation of SmI from samarium and diiodomethane, uteriohex-3-enoic acid, a transformation of methyl cinna-
2
[
10]
1
,2-diiodoethane, or iodine.
mate into methyl 2,3-dideuterio-3-phenylpropanoate,
pinacol coupling of benzaldehyde,
a
[
11]
a Reformatsky reac-
tion between cyclohexanone and ethyl 2-bromopropano-
[
a]
[12]
Departamento de Qu ´ı mica Org a´ nica e Inorg a´ nica, Universidad ate, and a carbonϪcarbon bond formation by a Barbier-
de Oviedo,
[13]
type reaction. The results are summarised in Table 1.
Juli a´ n Claver ´ı a 8, 33071 Oviedo, Spain
Fax: (internat.) ϩ 34-98/510-3446
E-mail: jmcg@sauron.quimica.uniovi.es
Taking into account the preceding results, we investigated
the effects that ultrasonic irradiation has on the generation
Eur. J. Org. Chem. 2003, 1775Ϫ1778
DOI: 10.1002/ejoc.200200669
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1775

J. M. Concell o´ n, H. Rodr ´ı guez-Solla, E. Bardales, M. Huerta
FULL PAPER
Table 1. Organic transformations carried out by CHI
3
generated
Table 2. Organic transformations carried out with SmI
from diiodomethane, 1,2-diiodoethane, and iodine
2
generated
SmI
2
[a]
Isolated yield based on the starting compound; all obtained com-
pounds were fully characterized by spectroscopic methods (IR,
NMR, and MS) and when possible compared with the spectro-
[
a]
Isolated yield based on the starting compound; all obtained com-
[b]
pounds were fully characterized by spectroscopic methods (IR,
NMR, and MS) and when possible compared with the spectro-
scopic data previously described.
scopic data previously described. SmI
2
was generated from sam-
was generated from samarium
was generated from samarium and
[c]
arium and diiodomethane. SmI
2
and 1,2-diiodoethane. [ SmI
d]
2
iodine.
of SmI starting from conventionally used iodo compounds
2
Conclusion
(
CH I , ICH CH I or I ). Here we described the prelimi-
2 2 2 2 2
nary results. Thus, the sonication of a mixture of samarium
and diiodomethane in THF rapidly afforded a deep blue
In conclusion we have described the first synthesis of
samarium diiodide in THF by using samarium and iodo-
form. This preparation, by ultrasonic irradiation of a mix-
ture of samarium powder and iodoform, is very rapid, sim-
solution of SmI (5Ϫ10 min). This solution was used to
2
carry out a β-elimination reaction (Table 2, Entry 1) and a
diiodomethylation of an aldehyde (Table 2, Entry 2).
In the same way, the sonication of a mixture of samarium
and 1,2-diiodoethane in THF afforded a deep blue solution
ple, and easy. The reactivity of SmI prepared in this way is
2
similar to the conventionally prepared material starting
from other iodo compounds. Preliminary results of the son-
of SmI in a short reaction time (10 min). This solution was
2
ical synthesis of SmI in THF from diiodomethane, 1,2-
2
used to perform the coupling of an α,β-unsaturated ester
diiodoethane, and iodine, are presented. Work is underway
to prepare SmBr in THF and SmI in solvents other than
[
14]
and an aldehyde and the transformation of an acid chlo-
ride into an α-diketone,[ (Table 2, Entries 3 and 4).
Ultrasonic irradiation also has beneficial effects on the
2
2
15]
THF employing sound waves.
generation of SmI in THF from iodine. The THF solution
2
of SmI obtained was used to transform cyclohexanone into Experimental section
2
16]
1
-iodomethylcyclohexan-1-ol,[ (Table 2, Entry 5).
All products were obtained in similar or higher yields to General Remarks: Reactions requiring an inert gas were conducted
under dry nitrogen, and the glassware was oven-dried (120 °C).
THF was distilled from sodium/benzophenone ketyl immediately
prior to use. All reagents were purchased in the highest quality
those previously reported.
This preparation of samarium diiodide by using ultra-
sonic irradiation has several advantages in comparison to
conventional methodology: a) activation of samarium pow-
der by heating is not necessary; b) addition of THF and the
corresponding iodo compound is carried out in one por-
tion; c) commercial iodo compounds (without purification)
1
available and were used without further purification. H NMR
spectra were recorded at 200, 300, or 400 MHz. 13C NMR spectra
and DEPT experiments were determined at 50, 75, or 100 MHz.
GC-MS and HRMS were measured at 70 eV. Chemical shifts are
given in δ (ppm) relative to TMS as internal standard in the case
1
13
can be used, and d) the reaction time is considerably of H NMR spectra and relative to CDCl3 in the case of
shorter. NMR spectra.
C
1776
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 1775Ϫ1778

Very Rapid Preparation of SmI
2
FULL PAPER
Synthesis of SmI
Samarium powder (0.172 g, 1.1 mmol) was placed in a Schlenk
tube at room temperature and dry THF (12 mL) was added. The (CH), 78.9 (CH), 126.9 (CH), 127.6 (CH), 127.7 (CH), 128.2 (CH),
2
by Sonication of Samarium Powder and Iodoform:
(200 MHz, CDCl
(meso), 6.9Ϫ7.4 (m, 10 H). C NMR (50 MHz, CDCl ): δ ϭ 77.6
3
3
): δ ϭ 4.0 (br. s, 2 H), 4.70 (Ϯ) (s, 2 H), 4.80
1
3
Schlenk tube was then partially submerged to the solvent level in
a conventional cleaner sonicator (ultrasound laboratory cleaner
129.9 (CH), 133.3 (CH), 139.6 (C), 139.7 (C) ppm. IR: ν˜ ϭ 3390,
1950, 1884, 1682, 1602, 1584, 1494, 1453, 1022 cm . R ϭ 0.4
f
Ϫ1
230 V, 150 W, 50 Hz) and iodoform (0.27 g, 0.7 mmol) was added.
(hexane/EtOAc, 10:1).
After 5 min, a deep blue solution of SmI was obtained.
2
Ethyl 2-(1-Hydroxycyclohexyl)propionate (1e): To a THF solution
of SmI (2 mmol) was added a solution of cyclohexanone (0.10 mL,
1 mmol) in THF (5 mL) and then ethyl 2-bromopropanoate
(0.13 mL, 1 mmol) in THF (5 mL). The resulting mixture was
Ethyl (E)-2-Methyl-3-(4-methoxyphenyl)propenoate (1a): A solution
of SmI (1.6 mmol) in THF (19 mL) was added dropwise, under
nitrogen, to a stirred solution of ethyl 2-methyl-3-(4-methoxyphe-
2
2
nyl)-2,3-epoxypropanoate (0.094 g, 0.4 mmol) in THF (4 mL) at stirred at room temperature for 10 min and then quenched with
room temperature. The reaction mixture was stirred for 90 min, and aqueous HCl (0.1 ⁾. Usual workup and purification by column
then quenched with aqueous HCl (0.1 ). Usual workup afforded flash chromatography provided the pure β-hydroxy ester. Yield:
1
the crude (E)-α,β-unsaturated ester which was purified by flash col-
194.0 mg (97%). H NMR (200 MHz, CDCl
3
): δ ϭ 1.13 (d, J ϭ
umn chromatography on silica gel (hexane/ethyl acetate, 10:1).
7.2 Hz, 3 H), 1.22 (t, J ϭ 7.1 Hz, 3 H), 1.40Ϫ1.60 (m, 10 H), 2.43
1
Yield: 74.8 mg (85%). H NMR (300 MHz, CDCl
3
): δ ϭ 1.33 (t, (q, J ϭ 7.2 Hz, 1 H), 3.01 (br. s, 1 H), 4.11 (q, J ϭ 7.1 Hz, 2 H)
1
3
J ϭ 7.1 Hz, 3 H), 2.12 (s, 3 H), 3.80 (s, 3 H), 4.25 (q, J ϭ 7.1 Hz,
ppm. C NMR (50 MHz, CDCl
H), 6.89 (d, J ϭ 8.3 Hz, 2 H), 7.37 (d, J ϭ 8.3 Hz, 2 H), 7.60 (s, 21.4 (CH ), 21.7 (CH ), 25.5 (CH
H) ppm. 13C NMR (75 MHz, CDCl
): δ ϭ 13.9 (CH ), 14.2 (CH), 60.2 (CH ), 71.1 (C), 176.8 (C) ppm. MS (70 eV): m/z (%) ϭ
), 55.0 (CH ), 60.6 (CH ), 113.6 (CH), 126.1 (C), 128.3 (C), 200 (2) [M ], 157 (35), 144 (29), 111 (18), 102 (100), 99 (59), 98
31.2 (CH), 138.2 (CH), 159.4 (C), 168.8 (C) ppm. MS (70 eV): (30), 81 (62), 74 (61), 56 (46), 55 (57), 45 (24), 43 (45), 41 (49). IR:
3
): δ ϭ 11.3 (CH
3
), 13.9 (CH
3
),
2
1
2
2
2
), 33.6 (CH ), 36.7 (CH
2
2
), 47.7
3
3
2
ϩ
(CH
3
3
2
1
ϩ
m/z (%) ϭ 220 [M ] (100), 191 (32), 175 (85), 147 (83). IR: ν˜ ϭ ν˜ ϭ 3441, 2936, 2862, 1712, 1636, 1457, 1373, 1334, 1260, 1183,
Ϫ1
Ϫ1
2
975, 1702, 1605 cm . R
f
ϭ 0.4 (hexane/EtOAc, 5:1).
f
1097, 1049, 961 cm . R ϭ 0.4 (hexane/EtOAc, 5:1).
(
E)-2,5-Dideuteriohex-3-enoic Acid (1b): Under nitrogen, a solution
of SmI (1.2 mmol) in THF (15 mL) was added dropwise to a and Diiodomethane: The sonication of of samarium powder
stirred solution of sorbic acid in D
2
Synthesis of SmI by Sonication of a Mixture of Samarium Powder
2
2
O (2 mL) and THF (2 mL) at
(0.172 g, 1.1 mmol) and diiodomethane (0.08 mL, 1.1 mmol) in
room temperature. The reaction mixture was stirred for 30 min and
then treated with 0.1  aqueous HCl. Standard workup afforded
the crude dideuterioacid, which was purified by flash column chro-
THF (12 mL) at room temperature for 5Ϫ10 min afforded a deep
blue solution of SmI
2
.
(
E)-N,N-Diethyl-4-phenylpent-2-enamide (1f): A solution of SmI
2
matography on silica gel (hexane/ethyl acetate, 5:1). Yield: 40.6 mg
1
(1 mmol) in THF (12 mL) was added very slowly dropwise, under
nitrogen, to a stirred solution of 2-chloro-N,N-diethyl-3-hydroxy-4-
phenylpentanamide (0.104 g, 0.4 mmol) in THF (2 mL) at room
temperature. After 30 min, the reaction was quenched with aque-
ous HCl (1 ). Usual workup provided the crude α,β-unsaturated
amide, which was purified by flash column chromatography on sil-
(
88%). H NMR (300 MHz, CDCl
3
): δ ϭ 0.99 (d, J ϭ 7.4 Hz, 3
H), 1.99Ϫ2.09 (m, 1 H), 3.03Ϫ3.08 (m, 1 H), 5.50 (dd, J ϭ 15.2,
.9 Hz, 1 H), 6.65 (dd, J ϭ 15.2, 5.3 Hz, 1 H), 10.46 (br. s, 1 H)
5
13
ppm. C NMR (75 MHz, CDCl
3 3
): δ ϭ 13.2 (CH ), 25.1 (t, J ϭ
1
9.4 Hz, CHD), 37.5 (t, J ϭ 19.5 Hz, CHD), 119.7 (CH), 136.8
ϩ
(
CH), 178.7 (C) ppm. MS (70 eV): m/z (%) ϭ 116 (63) [M ], 70
63), 56 (100), 42 (85). HRMS: calcd. for C 116.0804,
ϭ 0.5 (hexane/
ica gel (hexane/ethyl acetate, 3:1) to provide the pure compound.
(
6
Ϫ1
8 2 2
H D O
1
Yield: 83.2 mg (91%). H NMR (300 MHz, CDCl
3
): δ ϭ 0.94Ϫ1.32
found 116.0810. IR: ν˜ ϭ 3325, 2964, 1713 cm . R
f
(
(
m, 6 H), 1.43 (d, J ϭ 7.0 Hz, 3 H), 3.32 (q, J ϭ 7.0 Hz, 2 H), 3.41
q, J ϭ 7.0 Hz, 2 H), 3.65Ϫ3.68 (m, 1 H), 6.13 (d, J ϭ 15.2 Hz, 1
EtOAc, 3:1).
1
3
Methyl 2,3-Dideuterio-3-phenylpropanoate (1c): Successive treat-
H), 7.07 (dd, J ϭ 15.2, 7.0 Hz, 1 H), 7.20Ϫ7.33 (m, 5 H) ppm.
C
ment of methyl cinnamate (0.065 g, 0.4 mmol) in THF (2 mL) with NMR (75 MHz, CDCl
SmI (1.1 mmol) in THF (12 mL) for 30 min, at room temperature, 40.7 (CH ), 42.1 (CH ), 42.1 (CH), 119.3 (CH), 126.4 (CH), 127.2
and then with D
,3-dideuterio-3-phenylpropanoate which was purified by flash col-
3 3 3 3
): δ ϭ 13.0 (CH ), 14.7 (CH ), 20.7 (CH ),
2
2
2
2
O (2 mL) over a period of 30 min, afforded methyl
(CH), 128.4 (CH), 143.9 (C), 149.5 (CH), 165.7 (C) ppm. MS
(70 eV): m/z (%) ϭ 231 (89) [M ], 159 (92), 131 (85), 126 (100), 91
ϩ
2
umn chromatography on silica gel (hexane/ethyl acetate, 10:1). (81), 77 (36). HRMS: calcd. for C15H21NO 231.1623, found
1
Ϫ1
Yield: 64.7 mg (97%). H NMR (300 MHz, CDCl
3
): δ ϭ 2.63 (d,
231.1627. IR: ν˜ ϭ 3008, 2945, 1647 cm . R
f
ϭ 0.1 (hexane/
J ϭ 8.3 Hz, 1 H), 2.94 (d, J ϭ 8.3 Hz, 1 H), 3.68 (s, 3 H), 7.19Ϫ7.33 EtOAc, 5:1).
(
1
m, 5 H) ppm. 13C NMR (75 MHz, CDCl
9.8 Hz, CHD), 35.2 (t, J ϭ 19.8 Hz, CHD), 51.5 (CH
3
): δ ϭ 30.5 (t, J ϭ
), 126.2
1
,1-Diiodononan-2-ol (1g): To a solution of octanal (0.078 mL,
3
0.5 mmol) and iodoform (0.4 g, 1 mmol) in THF (18 mL) was ad-
(
(
(
(
CH), 128.2 (CH), 128.4 (CH), 140.3 (C), 173.3 (C) ppm. MS
ϩ
2
ded dropwise, under nitrogen, SmI (2 mmol) at 0 °C. The mixture
70 eV): m/z (%) ϭ 166 (40) [M ], 135 (12), 107 (37), 106 (100), 92
65). IR: ν˜ ϭ 3085, 3027, 2958, 1738, 1496, 1435 cmϪ1. R
was stirred for 45 min and then was quenched by addition of aque-
ous HCl (0.1 ). Usual workup afforded the crude diiodo alcohol
which was purified by flash column chromatography on silica gel
f
ϭ 0.3
hexane/EtOAc, 10:1).
1
,2-Diphenylethanediol (1d): Benzaldehyde (0.08 mL, 2 mmol), dis-
solved in THF (5 mL), was added at room temperature under nitro-
gen, to a 0.1  solution of SmI
typical blue color of SmI immediately turned orange. After stirring
(polarity gradient, from hexane to hexane/ethyl acetate, 10:1).
1
Yield: 110.9 mg (56%). H NMR (200 MHz, CDCl
3
): δ ϭ 0.87 (m,
2
in THF (20 mL, 2 mmol). The 3 H), 1.18Ϫ1.74 (m, 12 H), 2.40 (br. s, 1 H), 3.15 (br. s, 1 H), 5.28
1
3
2
(d, J ϭ 3.0 Hz, 1 H) ppm. C NMR (50 MHz, CDCl
(CH), 14.0 (CH ), 22.5 (CH ), 25.3 (CH ), 29.0 (CH ), 29.3 (CH
31.6 (CH ), 36.0 (CH ), 77.3 (CH) ppm. MS (70 eV): m/z (%) ϭ
396 [M ] (15), 269 (48), 170 (40), 123 (56), 81 (100), 55 (60), 41
(74). HRMS: calcd. for C O 395.9447, found 395.9449. IR:
3
): δ ϭ Ϫ9.4
for 10 min, a yellow precipitate appeared. Hydrolysis with 0.1 
HCl, followed by diethyl ether extraction and washing of the ex-
tract with sodium thiosulfate and saturated NaCl solution gave the
corresponding pinacol. Yield: 203.3 mg (95%).
3
2
2
2
2
),
2
2
ϩ
1
H
NMR
9 18 2
H I
Eur. J. Org. Chem. 2003, 1775Ϫ1778
www.eurjoc.org
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1777

J. M. Concell o´ n, H. Rodr ´ı guez-Solla, E. Bardales, M. Huerta
FULL PAPER
ν˜ ϭ 3402, 3410, 2924, 1076, 1464 cmϪ1. R
ϭ 0.3 (hexane/EtOAc,
f
Acknowledgments
10:1).
We thank III Plan Regional de Investigaci o´ n del Principado de
Asturias (PB-EXP01-11) and Ministerio de Educaci o´ n y Cultura
Preparation of SmI
2
by Sonication of a Mixture of Samarium Pow-
der and 1,2-Diiodoethane: Samarium powder (0.275 g, 1.6 mmol)
was placed in a Schlenk tube at room temperature with 1,2-diiodoe-
thane (0.451 g, 1.6 mmol) and then dry THF (20 mL) was added.
The Schlenk tube was partially submerged to the solvent level in
the sonicator. After sonication for 15 min, a deep blue solution of
(
BQU2001-3807) for financial support. J. M. C. thanks Carmen
Fern a´ ndez-Fl o´ rez for her time. H. R. S. and E. B. thank Principado
de Asturias and M. H. the Ministerio de Ciencia, Cultura y
Deportes for a predoctoral fellowship. Robin Walker revised the
English of the manuscript.
SmI
2
was obtained.
2-Cyclohexyl-4-methyloxolan-2-one (1h):
A
solution of SmI
2
(
3 mmol) in THF (30 mL) was added dropwise, under nitrogen, to a
[1]
J. L. Namy, P. Girard, H. B. Kagan, New J. Chem. 1977, 1,
stirred solution of cyclohexanecarboxaldehyde (0.12 mL, 1 mmol),
methyl but-2-enoate (0.214 mL, 2 mmol), 2-propanol (0.11 mL,
1
mixture was stirred for 1 min, and then quenched with aqueous
HCl (0.1 ⁾. Usual workup and purification by flash column chro-
5Ϫ7.
[2] [2a]
[2b]
J. A. Soderquist, Aldrichim. Acta 1991, 24, 15Ϫ23.
G.
[2c]
.5 mmol) and HMPA (1 mL) in THF (2 mL) at 0 °C. The reaction
A. Molander, Chem. Rev. 1992, 92, 29Ϫ68.
G. A. Molander,
C. R. Harris, Chem. Rev. 1996, 92, 307Ϫ338. [ G. A. Mo-
2d]
[
2e]
lander, C. R. Harris, Tetrahedron 1998, 54, 3321Ϫ3354.
A.
P. G.
[
2f]
1
Kief, A. M. Laval, Chem. Rev. 1999, 99, 745Ϫ777.
matography provided the pure lactone. Yield: 178.4 mg (98%). H
Steel, J. Chem. Soc., Perkin Trans. 1 2001, 2727Ϫ2751.
NMR (200 MHz, CDCl
J ϭ 6.8 Hz, 3 H), 0.80Ϫ1.31 (m, 10 H), 1.41Ϫ1.82 (m, 10 H),
.89Ϫ2.73 (m, 8 H), 3.61Ϫ3.99 (m, 2 H), 13C NMR (75 MHz,
CDCl ): δ ϭ 13.1 (CH ), 18.9 (CH ), 25.0 (CH ), 25.5 (CH ), 25.7
CH ), 26.0 (CH ), 27.5 (CH ), 38.4 (CH ), 27.6 (CH ), 28.7 (CH ),
0.0 (CH ), 31.6 (CH), 31.9 (CH), 36.8 (CH ), 37.1 (CH), 41.3
CH), 87.1 (CH), 90.9 (CH), 176.3 (C), 176.4 (C) ppm. MS (70 eV):
3
): δ ϭ 0.93 (d, J ϭ 6.8 Hz, 3 H), 1.08 (d,
[3]
Previously, we have described the generation of samarium di-
iodide from iodoform in situ, but no good results were ob-
tained: J. M. Concell o´ n, P. L. Bernad, J. A. P e´ rez-Andr e´ s,
Tetrahedron Lett. 1998, 39, 1409Ϫ1412.
To the best of our knowledge only one published paper de-
scribes ultrasonic generation of samarium diiodide (from Sm
and 1,2-diiodomethane). However, surprisingly, the reaction
time is longer than conventional methodology: L. Crombie, L.
J. Rainbow, J. Chem. Soc., Perkin Trans. 1 1994, 673Ϫ687.
S. Raucher, P. Klein, J. Org. Chem. 1981, 46, 3558Ϫ3559.
1
3
3
3
2
2
(
3
(
2
2
2
2
2
2
[4]
2
2
ϩ
m/z (%) ϭ 182 (Ͼ 1) [M ], 99 (33), 83 (16), 41 (100). IR: ν˜ ϭ 2922,
1
Ϫ1
773, 1450, 1171 cm . R
f
ϭ 0.2 (hexane/EtOAc, 5:1).
[
[
[
5] [5a]
[
[
5b]
5c]
Diphenylethanedione (1i): A solution of benzoyl chloride (0.09 mL,
T. Kitazume, N. Ishikawa, Chem. Lett. 1981, 1679Ϫ1680.
B-H. Han, P. Boudjouk, J. Org. Chem. 1982, 47,
0
.8 mmol) in THF (2 mL) was slowly added under nitrogen at room
temperature to 1.6 mmol of 0.1  SmI solution in THF. This solu-
tion turned yellow in a few minutes. Dilute HCl was then added.
After diethyl ether extraction, washing with aqueous NaHCO , and
5030Ϫ5032.
2
6]
7]
[6a]
Starting from 1,2-diiodoethane:
S. Lin, F. Yang, J. Shiue, S.
Yang, J. Fang, J. Org. Chem. 1998, 63, 2909Ϫ2917. [ G. A.
6b]
3
Molander, B. E. La Belle, G. Hahn, J. Org. Chem. 1986, 51,
5
drying with sodium sulfate, the α-diketone 1i was recovered after
recrystallization. Yield: 58.8 mg (71%). H NMR (200 MHz,
CDCl
CDCl
259Ϫ5264.
1
[7a]
Starting from 1,2-diiodoethane:
J. Marco-Contelles, P. Gal-
): δ ϭ 7.28Ϫ8.21 (m, 10 H) ppm. 13C NMR (50 MHz,
3
lego, M. Rodr ´ı guez-Fern a´ ndez, N. Khiar, C. Destabel, M.
3
): δ ϭ 128.9 (CH), 129.8 (CH), 132.9 (C), 134.8 (CH), 194.5
Bernab e´ , A. Mart ´ı nez-Grau, J. L. Chiara, J. Org. Chem. 1997,
ϩ
[7b]
(C) ppm. MS (70 eV): m/z (%) ϭ 210 (5) [M ], 105 (100), 77 (76),
62, 7397Ϫ7412. Starting from diiodomethane:
G. A. Mo-
Ϫ1
5
0
1 (35). IR: ν˜ ϭ 3061, 1682, 1596, 1449, 1265, 1211 cm . R
f
ϭ
lander, C. del Pozo Losada, J. Org. Chem. 1997, 62,
[7c]
.4 (hexane/EtOAc, 5:1).
2935Ϫ2943.
5
S. R. Angle, J. D. Rainier, J. Org. Chem. 1992,
7d]
7, 6883Ϫ6890. From iodine: [ D. P. Curran, X. Gu, W.
Zhang, P. Dowd, Tetrahedron 1997, 53, 9023Ϫ9042.
Synthesis of SmI
2
by Sonication of Samarium Powder and Iodine:
[7e]
M. J.
Samarium powder (0.172 g, 1.1 mmol) was placed in a Schlenk
tube at room temperature with iodine (0.25 g, 1 mmol) and then
dry THF (10 mL) was added. The Schlenk tube was partially sub-
merged to the solvent level in the sonicator. After sonication for
Totleben, D. P. Curran, P. Wipf, J. Org. Chem. 1992, 57,
1740Ϫ1744.
J. M. Concell o´ n, P. L. Bernad, E. Bardales, Org. Lett. 2002,
[
[
8]
9]
4
, 189Ϫ191.
J. M. Concell o´ n, H. Rodr ´ı guez-Solla, Chem. Eur. J. 2002, 8,
4
1
h, a deep blue solution of SmI
2
was obtained.
493Ϫ4497.
[
[
[
[
10]
11]
12]
13]
1-Iodomethylcyclohexanol (1j): A solution of SmI
2
(2.5 mmol) in
J. M. Concell o´ n, H. Rodr ´ı guez-Solla, Chem. Eur. J. 2001, 7,
4266Ϫ4271.
THF (25 mL) was added dropwise, under nitrogen, to a stirred
solution of cyclohexanone (0.10 mL, 1 mmol) and diiodomethane
J. L. Namy, J. Souppe, H. B. Kagan, Tetrahedron Lett. 1983,
24, 765Ϫ766.
(0.16 mL, 2 mmol) in THF (10 mL) at room temperature. The reac-
P. Girard, J. L. Namy, H. B. Kagan, J. Am. Chem. Soc. 1980,
02, 2693Ϫ2698.
J. Souppe, J. L. Namy, H. B. Kagan, Tetrahedron Lett. 1982,
3, 3497Ϫ3500.
tion mixture was stirred for 3 min, after which time the blue-green
color had turned to yellow. The reaction was then quenched with
aqueous HCl (0.1 ⁾. Usual workup and purification by flash col-
1
2
umn chromatography provided the iodo alcohol. Yield: 194.4 mg
[14]
[15]
[16]
K. Otsubo, J. Inanaga, M. Yamaguchi, Tetrahedron Lett. 1986,
1
(
3
2
81%). H NMR (200 MHz, CDCl
3
): δ ϭ 1.07Ϫ2.05 (m, 10 H),
): δ ϭ 21.2 (CH ),
2
), 68.9 (C) ppm. MS (70 eV):
27, 5763Ϫ5764.
.32 (s, 2 H) ppm. 13C NMR (50 MHz, CDCl
4.6 (CH ), 25.3 (CH ), 36.4 (CH
m/z (%) ϭ 240 (9) [M ], 127 (14), 113 (27), 99 (100). IR: ν˜ ϭ 3418,
f
931, 1446, 978 cm . R ϭ 0.4 (hexane/EtOAc, 3:1).
3
2
P. Girard, R. Couffignal, H. B. Kagan, Tetrahedron Lett. 1981,
22, 3959Ϫ3960.
T. Tabuchi, J. Inanaga, Tetrahedron Lett. 1986, 27, 3891Ϫ3894.
Received November 29, 2002
2
2
ϩ
Ϫ1
2
1778
 2003 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2003, 1775Ϫ1778