A novel indium-boron amorphous alloy mediator for barbier-type carbonyl allylation in aqueous medium

Article abstract of DOI:10.1002/adsc.201100064

A novel indium-boron (In-B) amorphous alloy was prepared by chemical reduction of indi- um(III) ions [In³⁺] with borohydride [BH ₄^-] in aqueous solution and was applied to the water-medium Barbier-type allylation reactions

Full text of DOI:10.1002/adsc.201100064

FULL PAPERS
DOI: 10.1002/adsc.201100064
A Novel Indium-Boron Amorphous Alloy Mediator for Barbier-
Type Carbonyl Allylation in Aqueous Medium
a,
a
a
a,
b
Hui Li, * Fuxing Dong, Mingwen Xiong, Hexing Li, * Ping Li,
b
and Xinggui Zhou
a
Department of Chemistry and The Education Ministry Key Lab of Resource Chemistry, Shanghai Normal University,
Shanghai 200234, Peopleꢀs Republic of China
Fax : (+86)-21-6432-2272; e-mail: lihui@shnu.edu.cnhexing-li@shnu.edu.cn
State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237,
Peopleꢀs Republic of China
b
Received: January 25, 2011; Revised: April 15, 2011; Published online: August 10, 2011
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/adcs.201100064.
Abstract: A novel indium-boron (In–B) amorphous and the high electron density on the In active sites
alloy was prepared by chemical reduction of indi- resulting from the strong electronic interaction be-
3+
À
4
um ACHTUNGTRENNUNG( III) ions [In ] with borohydride [BH ] in aque- tween the metal In and the alloying B. The yield of
ous solution and was applied to the water-medium target product over the In–B amorphous alloy was
Barbier-type allylation reactions. A variety of allyl similar to that obtained on the homogeneous Pd(II)
halides could be efficiently added to aldehydes or organometallic catalyst, showing good potential in
ketones in water. Additionally, the as-prepared In–B practical application.
exhibits much higher activity than the commercial In
powder and the crystallized In–B owing to the high Keywords: amorphous materials; Barbier reaction;
surface area, the unique amorphous alloy structure, cleaner organic synthesis; indium; water
Introduction
Amorphous alloys represent a new class of environ-
mentally friendly catalysts with higher activity, better
Homoallylic alcohols have been well known as impor- selectivity and stronger sulfur resistance than the cor-
tant building blocks in many biological active mole- responding crystalline catalysts owing to their unique
[
1]
cules, such as macrolides, polyether and antibiotics,
short-range ordering but long-range disordering struc-
[
7]
and can be achieved via Barbier-type reactions using ture. To date, a great number of amorphous alloys
organometallic reagents. Although highly active and have been synthesized via chemical reduction of met-
selective, homogeneous organometallic catalysis suf- allic ions with BH4 or/and H PO and their catalytic
fers from numerous drawbacks, namely, high cost, performances have been thoroughly investigated.
[
2]
À
À
2
2
[7d,e]
non-reusability of catalyst, sensitivity toward moisture To the best of our knowledge, however, indium-con-
and air, as well as the environmental pollution from taining amorphous alloy has never been reported so
[
3]
the presence of organic solvent. Recently, the use of far. We report here, with the aim to design powerful
water instead of organic solvents as reaction medium heterogeneous mediators for water-medium potential-
for organic synthesis has emerged as one of the most ly cleaner organic reactions, the synthesis of a novel
interesting fields for organic chemists because of sub- In–B amorphous alloy in the form of ultrafine nano-
[
4]
stantial economical and ecological gains. In 1990, particles, which exhibited much higher activity than
[5]
[6]
Li and Chan established the first utility of metallic either the commercial In powder or the crystallized
indium powder to mediate Barbier-type carbonyl ally- In–B during Barbier-type allylation reactions of car-
lation in aqueous media. Although highly selective, bonyl compounds in aqueous medium. The correla-
such indium powder exhibits lower efficiency for ally- tion of the reactivity to the structural characteristics
lation reactions in comparison with the homogeneous was tentatively established.
catalysts which limits its application.
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Results and Discussion
Structural Characteristics
The composition of the as-prepared In–B was deter-
mined as In B (Table 1) by inductively coupled
83
17
plasma-atomic emission spectroscopy (ICP-AES)
analysis.
The X-ray diffraction (XRD) pattern [Figure 1, (a)]
demonstrated that the fresh In–B sample was present
in a typical amorphous structure indicated by a single
[
8]
broad peak around 2q=328. This amorphous struc-
ture could be further confirmed by a series of succes-
sive diffraction halos in an attached selective area
electronic[ diffraction (SAED) image (inset in
9]
Figure 1). Heat treatment of the fresh In–B at 473 K
in argon for 2 h resulted in the appearance of various
crystalline diffraction peaks characteristic of metallic
Figure 1. XRD patterns of (a) the as-prepared In–B and (b)
indium (PDF 85-1409) [Figure 1, (b)]. Meanwhile, the the In–B treated at 473 K in an Ar flow for 2 h. The inset is
attached SAED image displayed diffraction dots indi- the SAED images of the samples.
cative of the crystalline structure. These results dem-
onstrated the transformation from an amorphous
[
10]
structure to the crystalline structure, together with the namically metastable structure. In addition, no sig-
decomposition of In–B alloys. Using a low stirring nificant endothermic peak corresponding to the melt-
speed (600 rpm), only crystalline metallic In diffrac- ing point of metallic In had been detected at around
tion peaks were observed from the XRD pattern (see 631 K as commercial metallic In powder [Figure 2,
Supporting Information, Figure S1). The formation of (b)], being attributed to the formation of In–B amor-
crystalline metallic In could be due to the crystalliza- phous alloy.
tion during the preparation process, taking into ac-
count that the reaction between In ions and BH4
The In 3d X-ray photoelectron spectroscopy (XPS)
spectra [Figure 3, (a)] revealed that for all In species
3+
À
was vigorous and strongly exothermic. Thus, the stir- in the as-prepared In–B sample, the binding energy
ring speed is of central importance for the formation (BE) values of In 3d5/2 and In 3d3/2 were 443.8 and
of In–B amorphous alloy.
451.4 eV, indicating that all In atoms were present in
[11]
The crystallization process was further investigated the metallic state. But the B species were present in
by differential scanning calorimetry (DSC) analysis. both the elemental B and the oxidized B, with B 1s
As shown in Figure 2, (a), the as-prepared In–B BE values of around 188.1 and 192.4 eV. The B 1s BE
sample displayed an exothermic peak at around of the elemental B in In–B exceeded that of pure B
[
12]
658 K, implying the features of the typical thermody- (187.1 eV) by 1.0 eV, further indicating that the ele-
[a]
Table 1. Structural parameters and performances of different mediators.
2
À1
S[b]
À3
À1
À2
Mediator
Composition [atom%] SBET [m g ] Conversion [%] Selectivity [%]
R
[ꢂ10 mmolmin m ]
In–B
Cryst. In–B
In powder
In B
135
88
110
–
96
47
85
96
98
97
98
96
2.3
1.0
1.9
–
8
3
17
17
[
c]
In B
83
In
–
[
d]
PdCl ACHTUNGTRENNUNG( PPh )
2 3 2
[
[
a]
b]
Reaction conditions: a mediator containing In (1.12 mmol), benzaldehyde (2.25 mmol), allyl bromide (4.50 mmol), Al
0.540 g), H O (10.0 mL), T=323 K, reaction time=120 min.
R is expressed as the amount of substance of benzaldehyde converted (at 10% conversion) per minute on per square
(
2
S
meter In site.
After being treated at 473 K for 2 h in an Ar flow.
The amount of catalyst is 150 mg.
[
[
c]
d]
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A Novel Indium-Boron Amorphous Alloy Mediator for Barbier-Type Carbonyl Allylation
Figure 2. DSC curves of (a) the In–B sample, and (b) the
commercial metallic In powder.
mental B is alloyed with the metallic In. In the In–B
alloys, some of the electrons may be transferred from
B to In, as had been detected in other M–B (M=Ni,
[12,13]
Co, Ru) samples.
Thus, the combined results from
XRD, SAED, DSC, and XPS characterizations clearly
demonstrated the formation of In–B amorphous alloy
3+
À
through the reduction of In by BH . According to
4
the calculation based on XPS peak areas, the surface
molar ratio of the alloying B to the metallic In in In–
B was 7/93.
The representative transmission electronic micros-
copy (TEM) image (Figure 4) revealed that the as-
prepared In–B amorphous alloy was present in the
form of uniformly ultrafine particles. The average par-
ticle size was about 8.5 nm (Figure 4). In contrast, the
commercial In powder showed almost irregular shape
with extremely broad particle size distribution, from
Figure 3. XPS spectra of the In–B sample: (a) In 3d, and (b)
B 1s.
<
10 nm to> 100 nm (see Supporting Information,
Figure S2). The relatively smaller size and narrow in Table 1. The relatively higher SBET of the as-pre-
distribution for the as-prepared In–B nanoparticles pared In–B amorphous alloy could be easily under-
could be attributed mainly to the rapid reduction of stood by considering its nanosized structure, which
3+
À
4
In by BH . When the stirring speed was set to was consistent with the TEM observations.
600 rpm while keeping other experimental conditions
as same as the typical preparation, large well-defined
hexagonal crystallines (ca. 100–150 nm) would be Reactivity
formed (see Supporting Information, Figure S3). The
corresponding SAED pattern showed periodic sharp The as-synthesized In–B amorphous alloy was sub-
diffraction points, indicated well-crystallized structure. jected to Barbier-type carbonyl allylation reactions in
¯
The pattern could be indexed as [032] zone axis of In aqueous medium. Figure 5 showed the reaction pro-
tetragonal phase (PDF 85-1409, I4/mmm). This is con- files of addition of allyl bromide to benzaldehyde
sistent with the aforementioned XRD characteriza- over In–B and the commercial In powder, which re-
tion, which showed diffraction peaks corresponding to vealed that both samples are highly selective towards
crystalline metallic In.
1-phenyl-3-buten-1-ol. The obtained ln(1Àconversion)
By an N physisorption experiment, the Brunauer– over In–B increased almost linearly with the reaction
2
Emmett–Teller (BET) surface areas (SBET) of all the time (inset in Figure 5), indicating that the present re-
In-containing samples were determined and are listed action was first-order with respect to benzaldehyde.
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Hui Li et al.
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Figure 4. TEM image (left) and its corresponding size distribution histogram (right) of an In–B sample.
Figure 5. Dependence of the benzaldehyde conversion and the 1-phenyl-3-buten-1-ol selectivity on reaction time over In–B
amorphous alloy and In powder: (
) conversion on In-B amorphous alloy; (&) selectivity on In–B amorphous alloy; (*) con-
&
version on In powder; (*) selectivity on In powder. Inset is the time vs. ln(1Àconversion) curve over In–B amorphous alloy.
Reaction conditions are listed in Table 1.
Along with the target product, the self-coupling prod- The role of Al powder is to regenerate In(0) species
uct of the allyl bromide, 1,5-hexadiene was also iden- in situ during the reaction.
tified in the reaction mixture. This suggested that this
Table 1 summarizes the catalytic properties of dif-
Barbier reaction followed a single-electron transfer ferent catalysts. All the In-containing samples exhibit-
[
3a,b]
(
SET) mechanism as proposed by Li and Chan,
in- ed high selectivity toward 1-phenyl-3-buten-1-ol. The
volving the formation of a radical anion intermediate. as-prepared In–B amorphous alloy was more active
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Adv. Synth. Catal. 2011, 353, 2131 – 2136

A Novel Indium-Boron Amorphous Alloy Mediator for Barbier-Type Carbonyl Allylation
than the commercial In powder (Figure 5). Obviously, Table 3. In-mediated Barbier-type allylation of acetopheno-
[a]
ne.
the higher reactivity may be attributed to both the
higher S and the enhanced intrinsic reactivity (see
the R values in Table 1). This could be supported by
the fact that an abrupt decrease in reactivity was ob-
served for the In–B treated at 473 K for 2 h in an
argon flow (Table 1), which was firstly due to the sig-
BET
S
nificant agglomeration of In–B nanoparticles at ele- Entry Catalyst L
vated temperature and, thus, decreasing SBET and, sec-
Time
[h]
Conversion Selectivity
[%]
[%]
S
ondly, the decrease in R resulted from the crystalliza-
[
b]
1
2
3
4
5
In–B
In–B
In–B
In–B
In
B
A
H
U
G
R
N
U
(pin) 12
90
58
71
90
73
93
98
97
94
95
tion and decomposition of In–B amorphous alloy. The
larger R of In–B amorphous alloy could be interpret-
Cl
Br
Br
Br
12
12
24
24
S
ed in terms of both the structural and electronic ef-
fects: (i) Structure effect: the unique short-range or-
dering but long-range disordering amorphous struc-
ture endowed In–B amorphous alloy with more
highly unsaturated In active sites and stronger syner-
gistic effect between these active sites, which may
promote the adsorption of reactants and favor reactiv-
powder
[
a]
Reaction conditions:
a
mediator containing In
1.12 mmol), acetophenone (2.00 mmol), allyl substance
3.00 mmol), Al (0.540 g), H O (10.0 mL), T=323 K.
(
(
2
[b]
T=303 K.
[
14]
ity.
(ii) Electronic effect: the aforementioned XPS
spectra demonstrated the strong electronic interaction
between In and B in the In–B amorphous alloy, tions. Furthermore, In–B was even active for allylic
making In electron-enriched while B is electron-defi- chloride substrate, which could react with benzalde-
cient. The higher electron density on In active sites hyde to give the corresponding allylation product in
might benefit the formation of the radical anion inter- high yield (entry 4 in Table 2).
mediate through SET processes, which could promote
To extend the scope of Barbier-type carbonyl allyla-
the allylation reaction. The maximum yield of 1- tion reaction, we examined the allylation of acetophe-
phenyl-3-buten-1-ol could reach 94% over the as-pre- none in water (Table 3). The investigation started
pared In–B amorphous alloy, almost the same as that with the reaction of acetophenone and allylboronate
obtained by using the PdCl2
alyst (see Table 1).
ACHTUNGTRENNUNG( PPh ) homogeneous cat- (pin=pinacolyl) in water; the as-prepared In–B amor-
3 2
phous alloy gave a similarly high yield (84%) of 2-
Table 2 demonstratesthat In–B was an active medi- phenyl-4-penten-2-ol (entry 1 in Table 3) to that re-
[
15]
ator for the Barbier-type allylation reactions of vari- ported by Kobayashiꢀs group.
Even if the desired
ous aldehydes and allylic halides in water. The reac- product was obtained in high yield, the potential ap-
tions of aldehydes with electron-withdrawing or elec- plication is still limited due to the high cost of allyl-
tron-donating groups did not show obvious difference boronate. Clearly, with respect to cost concern, the
(
entries 1–3 in Table 2). This means that the reaction use of simple allyl halides is appreciated. Further ex-
is relatively insensitive to the electronic characteristics periments showed that the as-prepared In–B amor-
of the substituents under the present reaction condi- phous alloy could mediate allylation of acetophenone
with either allyl bromide or allyl chloride in moderate
yields (entries 2 and 3 in Table 3). Most notably, by
[
a]
increasing the reaction time to 24 h, in the presence
of In–B, allyl bromide reacted with acetophenone to
yield the desired nucleophilic addition product in high
yield (entry 4 in Table 3). Meanwhile, the as-prepared
In–B amorphous alloy displayed enhanced reactivity
over the commercial In powder (entry 5 in Table 3).
Both the high dispersion of In active sites and the
unique amorphous structure were likely responsible
for the enhanced activity.
Table 2. In-B mediated Barbier-type allylation of aldehyde.
Entry
R
X
Conversion [%]
Selectivity [%]
1
2
3
4
H
CH3
Cl
Br
Br
Br
Cl
96
94
97
95
98
98
97
98
H
Conclusions
[
a]
Reaction conditions:
a
mediator containing In
1.12 mmol), aldehyde (2.25 mmol), allyl halide
In summary, we have achieved the first synthesis of
4.50 mmol), Al (0.540 g), H O (10.0 mL), T=323 K, re- In–B amorphous alloy, which exhibited high activity
(
(
2
action time=120 min.
and selectivity in water-medium Barbier-type carbon-
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Hui Li et al.
FULL PAPERS
yl allylation reactions owing to the promotional ef- (containing 1.12 mmol In) and Al powder (0.54 g), and the
mixture was stirred vigorously at 323 K. Reaction samples
fects from the high surface area, the unique amor-
were taken at regular intervals and monitored by GC (Agi-
phous alloy structure, as well as strong electronic in-
lent GC 1790 equipped with a HP-5 capillary column).
teraction in the In–B alloy. This work might hold
After complete reaction, the mediator was recovered
promise for new applications of amorphous alloys in
through centrifugation and subsequently washed thoroughly
catalysis besides hydrogenations and also offer oppor-
with ethyl acetate. After extraction with ethyl acetate, the
tunities to design efficient mediators for water-
medium potentially cleaner organic synthesis.
product was analyzed by GC, from which the conversion of
acetophenone and the selectivity to allylic alcohol were cal-
culated.
Experimental Section
Catalyst Preparation
Acknowledgements
All of the chemicals used in this experiment were of analyti-
cal grade and used without further purification. In–B amor-
phous alloy was prepared by a chemical reduction method
in the following procedure: a KBH4 aqueous solution
This work is supported by the National Natural Science
Foundation of China (20973113, 20825724), the 973 Program
(2009CB226106), Shanghai Government (09JC1411400,
10SG41, S30406, 07dz22303), and State Key Laboratory of
Chemical Engineering (SKL-ChE-09C03).
(
2.5 mL, 2.0M) was added dropwise into an InCl aqueous
3
solution (2.5 mL, 0.45M) under vigorous stirring (>
00 rpm) at 283 K. After complete reaction, the black pre-
8
À
+
cipitate was washed free from Cl or K ions with deionized
water until the pH reached 7, and finally soaked in water
until the time of use.
References
[
[
[
1] W. R. Roush, in: Comprehensive Organic Synthesis,
Ed.: B. M. Trost), New York, Pergamon, 1991, p 1.
2] A. Shuki, J. J. Shun, I. Yoshiyuki, Bull. Chem. Soc. Jpn.
992, 65, 1736.
3] a) C. J. Li, Chem. Rev. 1993, 93, 2023; b) T. H. Chan,
C. J. Li, M. C. Lee, Z. Y. Wei, Can. J. Chem. 1994,72,
Catalyst Characterization
(
The bulk composition was analyzed by means of ICP
1
(
Varian VISTA-MPX). The amorphous structure was deter-
mined by both XRD (Rigaku D/Max-RB with Cu Ka radia-
tion) and SAED (JEOL JEM-2100). The crystallization pro-
cess was followed by DSC (Shimadzu DSC-60) under an N
atmosphere at the heating rate of 10 Kmin . The surface
morphology was observed by TEM (JEOL JEM-2100). The
surface electronic states and surface composition were inves-
tigated by XPS (ULVAC-PHI PHI5000 VersaProbe using Al
Ka radiation), during which the In–B sample was dried and
pretreated in situ in a pure Ar atmosphere to avoid oxida-
tion. The BE values were calibrated by using C 1s=
1
181; c) C. J. Li, Chem. Rev. 2005, 105, 3095.
2
À1
[4] a) F. Joh, Acc. Chem. Res. 2002, 35, 738; b) S. Narayan,
J. Muldoon, M. G. Finn, V. V. Fokin, H. C. Kolb, K. B.
Sharpless, Angew. Chem. 2005, 117, 3339; Angew.
Chem. Int. Ed. 2005, 44, 3275; c) K. H. Shaughnessy,
Eur. J. Org. Chem. 2006, 67, 1827; d) C. J. Li, L. Chen,
Chem. Soc. Rev. 2006, 35, 68.
[
[
5] C. J. Li, T. H. Chan, Tetrahedron Lett. 1991, 32, 7017.
6] T. H. Chan, C. J. Li, J. Chem. Soc. Chem. Commun.
2
84.6 eV as a reference. N adsorption-desorption isotherms
2
1
992, 747.
were obtained at 77 K using a Quantachrome NOVA 4000e
apparatus. SBET was calculated by using the multiple-point
BET method in the relative pressure range of P/P =0.05–
[
7] a) J. Van Wonterghem, S. Mørup, C. J. W. Koch, S. W.
Charles, S. Wells, Nature 1986, 322, 622; b) A. Molnar,
G. V. Smith, M. Bartok, Adv. Catal. 1989, 36, 329; c) A.
Baiker, Faraday Discuss. Chem. Soc. 1989, 87, 239;
d) Y. Chen, Catal. Today 1998, 44, 3; e) J. F. Deng,
H. X. Li, W. J. Wang, Catal. Today 1999, 51, 113.
0
0.3.
Activity Tests
Allylation of aldehydes: In a typical experiment, aldehyde
[8] A. Yokoyama, H. Komiyama, H. Inoue, T. Masumoto,
H. M. Kimura, J. Catal. 1981, 68, 355.
[9] S. Klein, J. A. Martens, R. Parton, K. Vercruysse, P. A.
Jacobs, W. F. Maier, Catal. Lett. 1996, 38, 209.
[10] F. Ye, K. Lu, J. Non-Cryst. Solids 2000, 262, 228.
[11] P. Sen, M. S. Hegde, C. N. Rao, Appl. Surf. Sci. 1982,
10, 63.
(
2.25 mmol) and allyl halide (4.5 mmol) were added into
water (10.0 mL). To this were added mediator (containing
.12 mmol In) and Al powder (0.54 g), and the mixture was
1
stirred vigorously at 323 K. Reaction samples were taken at
regular intervals and monitored by GC (Agilent GC 1790
equipped with a HP-5 capillary column). After complete re-
action, the mediator was recovered through centrifugation
and subsequently washed thoroughly with ethyl acetate.
After extraction with ethyl acetate, the product was ana-
lyzed by GC, from which the conversion of aldehyde and
the selectivity to allylic alcohol were calculated.
[12] H. Li, H. X. Li, W. L. Dai, W. J. Wang, Z. G. Fang, J. F.
Deng, Appl. Surf. Sci. 1999, 152, 25.
[13] a) H. Li, J. Liu, S. H. Xie, M. H. Qiao, W. L. Dai, H. X.
Li, J. Catal. 2008, 259, 104; b) H. Li, Y. Wang, Q. F.
Zhao, H. X. Li, Res. Chem. Intermed. 2009, 35, 779.
[14] G. D. Angel, J. L. Benitez, J. Mol. Catal. 1994, 94, 409.
[15] U. Schneider, M. Ueno, S. Kobayashi, J. Am. Chem.
Soc. 2008, 130, 13824.
Allylation of acetophenone: In a typical experiment, ace-
tophenone (2.0 mmol) and allyl halide (3.0 mmol) were
added into water (10.0 mL). To this were added mediator
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