A highly selective synthesis of 1,1'-Bi-2-naphthol by oxidative coupling of naphthol on mesoporous Fe,Cu/MCM-41 aluminosilicates

Article abstract of DOI:10.1002/(sici)1099-0690(199908)1999:8<1915::aid-ejoc1915>3.0.co;2-1

The oxidative coupling of 2-naphtol to 2,2'-dihydroxy-1,1'-binaphthyl (binaphthol) by air or oxygen has been carried out in the presence of Cu²⁺- and Fe³⁺-doped MCM-41 aluminosilicate as catalyst. Fe-exchanged MCM-41 was found to be a very efficient catalyst; excellent mass balances (> 95%) with almost total conversion and selectivity to binaphthol were achieved. The same reaction has also been carried out on Cu²⁺- and Fe³⁺-Y zeolites. Taking into account the relative dimensions of binaphthol and the catalyst pores, molecular modeling predicts that binaphthol can be accommodated inside the zeolite Y supercages (1.3 nm), but it cannot diffuse outside the zeolite cavities through the smaller pore apertures (0.74 nm). This prediction has been confirmed by dissolving a Y zeolite after the reaction, whereby unextractable binaphthol entrapped within the cavities was recovered. Variable amounts of two secondary by-products have also been detected, and their structure assigned to (2,8');(8,2')-dioxo-1,1'-binaphthyl and bisnaphthofuran based on analytical and spectroscopic data. Their percentage is particularly high when alumina-supported CuSO₄ is used as the catalyst.

Full text of DOI:10.1002/(sici)1099-0690(199908)1999:8<1915::aid-ejoc1915>3.0.co;2-1

FULL PAPER
A Highly Selective Synthesis of 1,1Ј-Bi-2-naphthol by Oxidative Coupling
of Naphthol on Mesoporous Fe,Cu/MCM-41 Aluminosilicates
[
a]
[a]
[a]
[a]
Elvira Armengol, Avelino Corma,* Hermenegildo Garc ´ı a,* and Jaime Primo
Keywords: Heterogeneous catalysis / Synthesis of binaphthol / MCM-41 / Zeolites
The oxidative coupling of 2-naphtol to 2,2Ј-dihydroxy-1,1Ј-
it cannot diffuse outside the zeolite cavities through the
smaller pore apertures (0.74 nm). This prediction has been
confirmed by dissolving a Y zeolite after the reaction,
whereby unextractable binaphthol entrapped within the
cavities was recovered. Variable amounts of two secondary
binaphthyl (binaphthol) by air or oxygen has been carried
2
+
3+
out in the presence of Cu - and Fe -doped MCM-41
aluminosilicate as catalyst. Fe-exchanged MCM-41 was
found to be a very efficient catalyst; excellent mass balances
(Ͼ 95%) with almost total conversion and selectivity to by-products have also been detected, and their structure
binaphthol were achieved. The same reaction has also been assigned to (2,8Ј);(8,2Ј)-dioxo-1,1Ј-binaphthyl and
2+
3+
carried out on Cu – and Fe –Y zeolites. Taking into account
the relative dimensions of binaphthol and the catalyst pores,
molecular modeling predicts that binaphthol can be
accommodated inside the zeolite Y supercages (1.3 nm), but
bisnaphthofuran based on analytical and spectroscopic data.
Their percentage is particularly high when alumina-
supported CuSO is used as the catalyst.
4
Introduction
2
,2Ј-Dihydroxy-1,1Ј-binaphthyl (binaphthol) and a large
variety of its derivatives are among the most widely used
chiral inductors for highly stereoselective catalytic reac-
[
1Ϫ5]
tions.
A large series of highly efficient enantioselective
Scheme 1. Oxidative coupling of 2-naphthol
catalytic complexes are based on binaphthol in order to
create the stereogenic space surrounding the active center.
The list of asymmetric reactions catalyzed by binaphthol
to organic molecules provided that their molecular sizes are
smaller than the dimensions of the pores. The application
[6][7]
derivatives includes DielsϪAlder cycloadditions,
ene re-
[
8][9]
[10][11]
actions,
Lewis acid catalyzed transformations,
en-
ϩ
of zeolites in their H form as solid acids in organic syn-
[12][13]
antioselective reduction of ketones,
macrocycles,
synthesis of chiral
thesis for the production of fine chemicals is an active area
of research in heterogeneous catalysis.
much less attention has been paid to the use of ion-ex-
changed zeolites as catalysts for oxidation reactions.
Herein, we report a study of the catalytic coupling of 2-
[
14]
[15]
asymmetric protonation,
and enantiose-
[28Ϫ31]
In contrast,
[16]
lective group transfer polymerization.
The most straightforward synthesis of binaphthols is the
oxidative coupling of the corresponding 2-naphthols
[
17][18]
(Scheme 1).
This coupling is usually promoted by
2ϩ
naphthol to binaphthol in the presence of a series of Cu
-
treating 2-naphthols with a molar excess of transition-metal
3ϩ
and Fe -exchanged mesoporous MCM-41 aluminosil-
icates as well as microporous Y zeolite. The selectivities to
binaphthol have been compared with those attained using
CuSO or Fe(NO ) supported on silica and alumina. As
III [19]
III [20]
II [21]
ions such as Fe ,
been reported that binaphthol can be obtained by using
either catalytic amounts of FeCl upon aerated ultrasound
Mn ,
and Cu .
It has, however,
3
4
3 3
[
22]
irradiation of 2-naphthols
or substoichiometric amounts
could be anticipated based on the relative molecular size of
binaphthol and the internal voids, mesoporous MCM-41
was found to be a much more convenient catalyst than
microporous Y zeolite, where a considerable portion of bi-
naphthol remains trapped inside the pores and is not ex-
tractable by solidϪliquid extraction.
II
[23][24]
of Cu Ϫamine complexes.
geneous catalytic processes have been developed by sup-
More recently, hetero-
[
25]
[26]
porting a CuSO Ϫ
and CuClϪamine complex
on
4
amorphous alumina.
Zeolites are crystalline aluminosilicates whose structure
is constructed by linking AlO and SiO tetrahedra creating
4
4
an open framework that defines channels and cages of vari-
ous shapes and sizes.[ These internal voids are accessible
27]
Results and Discussion
[
a]
Instituto de Tecnolog ´ı a Qu ´ı mica CSIC-UPV,
Universidad Polit e´ cnica de Valencia,
E-46071 Valencia, Spain
Fax: (internat.) ϩ 3496-387-7809
E-mail: hgarcia@vega.cc.upv.es
In zeolites, the large majority of the active sites (in our
case the transition-metal ions) are located in the interior of
the pores. Hence, zeolites are generally efficient catalysts
when the molecular size of reagents and reaction products
Eur. J. Org. Chem. 1999, 1915Ϫ1920

WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999
1434Ϫ193X/99/0808Ϫ1915 $ 17.50ϩ.50/0
1915

E. Armengol, A. Corma, H. Garc ´ı a, J. Primo
FULL PAPER
are smaller than the dimensions of the micropores and in- icates containing Cu2 or Fe3ϩ ions under the different con-
tracrystalline diffusion is, then, allowed. For large-pore zeo- ditions studied are collected in Table 1. Previous blank reac-
lites having apertures defined by 12-membered-ring oxygen tions performed without any catalyst under our experimen-
atoms, such as faujasites, the limiting diameter of the pores tal conditions showed that spontaneous, uncatalyzed
ϩ
˚
[32]
is around 7.4 A.
However, the crystal structure of tridi- formation of binaphthol from 2-naphthol only takes place
rectional Y zeolites encompasses much larger spherical cavi- to a very minor extent (< 2%). For the sake of comparison,
˚
ties (13 A in diameter). Therefore, it is possible to envisage Table 1 also contains the results achieved using CuSO or
4
a situation in which a bulky reaction product formed inside Fe(NO ) deposited on the external surface of nonporous
3
3
a large cage remains immobilized and trapped without any silica and alumina.
possibility of diffusing outside the cage. This is, in fact, the
As can be seen in Table 1 (entries 3Ϫ6), binaphthol is
case in this study, where a large binaphtol molecule can be present in the organic phase when the reaction is conducted
formed from a smaller 2-naphthol precursor. Binaphtol is a in the presence of Y zeolites as catalyst. This amount of
bulky, fairly rigid molecule in which free rotation around binaphthol is believed to correspond to that formed at those
the 1Ϫ1Ј CϪC bond connecting the two naphthyl moieties centers located in the more accessible outermost surface of
is restricted. Our semiempirical calculations at the AM1 le- the particles. Leaching out of some Cu2 or Fe ions from
ϩ
3ϩ
vel suggest that the dimensions of binaphthol are 11.53 ϫ the zeolite to the organic solution, which might lead to
˚
9
.14 ϫ 10.05 A along the principal three Cartesian axes of some degree of homogeneous catalysis, was ruled out by
the molecule. Accordingly, molecular modeling predicts filtering at 140°C a suspension of the zeolite and the reac-
that while binaphthol can be accommodated inside the tion mixture in chlorobenzene at 40% conversion and sub-
supercages of Y zeolites, it would be too bulky to diffuse sequently observing that this mixture does not vary in com-
˚
through the smaller 7.4 A windows of the Y supercage (Fig- position upon heating in the absence of the solid catalyst.
ure 1). Therefore, if binaphthol is formed inside the super- Furthermore, chemical analysis of the organic phase by
cages, it should remain immobilized and unextractable in- atomic absorption spectroscopy revealed that the concen-
side the zeolite Y catalyst.
trations of Cu or Fe metals was under the detection limit
for the technique (< 2 ppm).
Taking into account the results of the molecular model-
ing and given that binaphthol was present in the organic
phase using ion-exchanged Y zeolites as catalysts, we antici-
pated that another fraction of binaphthol could have been
formed inside the voids of the solid, but it would remain
trapped inside the big cavities. This is consistent with the
poor mass balances obtained when considering exclusively
the amount of reactants and products recovered from the
organic phases after the catalytic reaction. Indeed, thermo-
gravimetric analysis revealed that after the reaction the Y
zeolites contained between 10Ϫ20 wt-% of adsorbed or-
ganic material. Adding the weights of the organic material
retained in the catalyst estimated by thermogravimetry to
those of the organic material present in the liquid phase
(
see footnote a in Table 1), the final mass balances were
excellent (> 95%) in all cases. IR spectra of self-supported
wafers of these catalysts exhibit absorption bands in the
aromatic region compatible either with 2-naphthol, binaph-
thol, or a mixture of both compounds (Figure 2). However,
owing to the similarity between the IR spectra of naphthol
and binaphthol in the spectral window available where the
zeolite framework does not interfere, the exact nature and
composition could not be definitively determined by in
situ spectroscopy.
In order to conclusively establish that the material
trapped inside the zeolite Y corresponds, at least in part, to
binaphthol, we proceeded to dissolve a sample of FeY in
HF after its use as a catalyst (sample corresponding to en-
try 3 in Table 1). Previous controls indicate that neither
naphthol or binaphthol are affected by this treatment. After
dissolving a thoroughly Soxhlet-extracted FeY solid, only
Figure 1. Molecular modeling visualization of binaphthol encapsu-
lated inside the zeolite Y supercage
The same model predicts that diffusion of binaphthol in-
˚
side the 35 A channels of MCM-41 is not impeded. The
geometry of internal voids of mesoporous MCM-41 is
formed by an array of parallel hexagonal channels, the di-
ameter of which can be varied at will during the synthesis
˚
from 25 to 80 A depending on the chain length and concen-
tration of the alkyltrimethylammonium surfactant used as
[
27][33]
the template.
The results obtained for the coupling of naphthol to bi- binaphthol was recovered. This shows that the oxidative
naphthol in the presence of Y and MCM-41 aluminosil- coupling had also occurred inside the micropores, but the
1916
Eur. J. Org. Chem. 1999, 1915Ϫ1920

A Highly Selective Synthesis of 1,1Ј-Bi-2-naphthol by Oxidative Coupling
Table 1. Results of the formation of binaphthol from 2-naphthol in the presence of solid catalysts after 8 h reaction time
FULL PAPER
Entry
Catalyst
Conditions
Mass
Conversion
2-Naphthol (%)
Selectivity
[b]
Balance[ (%)
a]
Binaphthol (%)
1
2
3
4
5
6
7
8
9
NaY
HY
oxygen
oxygen
oxygen
air
100
80
< 2
15
65
62
48
26
68
99
86
99
79
98
37
84
0
Ϫ
Ϫ
[c]
[
d]
e]
e]
e]
FeY
100
100
98
46 (49)[
FeY
42 (34)
[
CuY
CuY
MCM-41
oxygen
air
42 (25)
[
98
12 (21)
[
f]
oxygen
oxygen
air
100
92
52
100
94
100
47
61
43
33
Ϫ
FeMCM-41
FeMCM-41
FeMCM-41
FeMCM-41
[g]
50
[
h]
10
11
12
13
14
15
16
17
18
19
20
oxygen
autoclave
oxygen
oxygen
autoclave
oxygen
oxygen
oxygen
air
100
100
100
100
100
100
98
CuMCM-41
CuMCM-41
CuMCM-41
[h]
SiO
2
CuSO
CuSO
CuSO
4
4
4
/SiO
/Al
/Al
2
46
97
94
39
65
80
[i]
2
O
O
3
99
88 (10)
[i]
2
3
84
87 (15)
Fe(NO
Fe(NO
3
)
)
3
/Al
/SiO
3
2
oxygen
oxygen
86
39
83
3
2
O
3
100
[
a]
[b]
Including the weight of organic material retained in the catalyst measured by thermogravimetry. Ϫ Secondary by-products account
[
c]
[d]
for 100%. Ϫ 2,2Ј-Dinaphthyl ether was formed in 75% selectivity. Ϫ The number within brackets corresponds to amount of binaph-
[e]
thol recovered after HF disaggregation of the solid. Ϫ The number in brackets corresponds to binaphthol retained in the solid measured
[f]
Ϫ [g]
by thermogravimetry. Ϫ Only traces of binaphthol (yield < 2%) were obtained in the absence of any catalyst.
The poor mass
[i]
[h]
˚
The pore size of this MCM-41 was 50 A. Ϫ The number in
balance is due to the presence of unidentified polymeric material. Ϫ
brackets corresponds to the selectivity of DOB.
the main product identified was 2,2Ј-dinaphthyl ether.[37]
Thus, it is the hydroxy group rather than the aromatic ring
that is the reactive functionality under acid catalysis, sug-
gesting that the reaction mechanism of binaphthol forma-
tion is related to the oxidizing ability of the active sites.
Both CuII and FeIII salts have previously been found to
be convenient reagents for the formation of binaphthol in
[
19,21,22]
homogeneous phase in stoichiometric amounts.
III
Table 1 reveals that the activity of Fe -exchanged alumino-
silicates is consistently significantly higher than those con-
II
taining Cu at similar levels of ion exchange.
As anticipated from their pore dimensions and molecular
sizes, the performance, based on the product found in the
organic phase, of ion exchanged MCM-41 catalysts is better
than that of zeolite Y. Eventually, under optimum con-
ditions, essentially 100% mass balances were achieved after
Figure 2. Aromatic region of the FT-IR spectra recorded at room
temperature of 2-naphthol (a), 2,2Ј-binaphthol (b) in KBr disks solidϪliquid extraction of the catalysts with excellent
and a self-supported wafer of CuMCM-41 aluminosilicate after
(
> 90%) conversion and selectivity (entries 8 and 10, Table
being used as catalyst for oxidative coupling of 2-naphthol and
Ϫ2
1). At the end of each run the ion-exchanged MCM-41
catalysts became heavily deactivated. However, an almost
complete recovery of the activity of FeMCM-41 for a se-
cond run was achieved upon calcination of the deactivated
catalyst at 500°C overnight under an oxygen stream.
outgased at 200°C under 10 Pa for 1 h
bulky product was unrecoverable by solidϪliquid extrac-
tion. An estimation of the number of binaphthols per
supercage indicates that at the maximum loading of the Y
catalysts (entry 3, Table 1) there is an average of one bi-
To learn about the influence of the pore size, we com-
naphthol for every three supercages. The successful immo- pared the results using two different batches of MCM-41
˚
bilization of binaphthol inside the zeolite Y supercages con- having diameters of 35 and 50 A, respectively. No signifi-
stitutes a new example of a ship-in-a-bottle synthesis of an cant improvement in the catalytic performance was ob-
[
34Ϫ36]
organic molecules by creation of new CϪC bonds.
served. This indicates that once the limiting diameter for
ϩ
Interestingly, the H form of the Y zeolite behaves in a the diffusion of binaphthol is reached, an increase in the
totally different way and does not promote the formation dimensions of the pore does not exert an appreciable influ-
of binaphthol (entry 2, Table 1). Using HY as the catalyst ence on the course of the reaction.
Eur. J. Org. Chem. 1999, 1915Ϫ1920
1917

E. Armengol, A. Corma, H. Garc ´ı a, J. Primo
FULL PAPER
We also noticed a beneficial influence of the oxygen par-
tial pressure on the rate of formation of binaphthol and the
yield achieved (Figure 3). However, it is worth mentioning
that the coupling of naphthol could also be conducted to a
lesser extent using a sealed autoclave or under Ar in the
absence of oxygen (entries 11 and 14 in Table 1). It is
reasonable to assume that in the absence of oxygen, the re-
action is no longer catalytic, but stoichiometric and eventu-
ally the oxidizing capacity of the zeolites has to be exhaus-
2
ϩ
3ϩ
ted. According to the Cu or Fe content of MCM-41
(
Ϫ1
0.532 and 0.770 mmol ϫ g , respectively) and the weights
of naphthol and catalyst used (see Experimental Section),
the maximum yield of binaphthol for a stoichiometric
transformation would be 27 and 38%, respectively. These
Figure 4. Time conversion plot for the oxidative coupling of 2-
4 2 3
predicted maximum yields agree quite well with the exper- naphthol in the presence of CuSO /Al O as catalyst showing the
secondary nature of DOB; 2-Naphthol (᭛), binaphthol (Ω), DOB
∆)
imental values achieved in the autoclave experiments (yields
of binaphthol in entries 11 and 14 of Table 1 are 37 and 28,
respectively; product yield ϭ mass balance ϫ conversion ϫ
(
selectivity). For those runs carried out in the presence of carbon of the other naphthyl ring is not without precedent
oxygen where the yield of binaphthol exceeded these values, in the literature.[
the reaction is truly catalytic and dioxygen is required to
38][39]
regenerate the active oxidation states of the metal ions.
Conclusion
Oxidative coupling of naphthol to binaphthol can be
conveniently carried out with almost total conversion and
Figure 3. Time conversion plot of the formation of binaphthol
catalyzed by FeMCM-41 in the presence of oxygen (•) or air (∆)
selectivity using Fe3 -exchanged MCM-41 in the presence
ϩ
of oxygen. In the case of large-pore Y zeolites, the conver-
At least two secondary by-products can be formed at
sions and selectivities measured in the liquid phase are
high 2-naphthol conversions. The percentage of these by-
moderate and, additionally, a significant amount of the bi-
products is particularly high using the CuSO -supported
4
naphthol is trapped and immobilized inside the zeolite cavi-
ties. Potential applications in catalysis of this ship-in-a-
bottle synthesis of binaphthol within the zeolite Y super-
cages could be developed in the future. This report consti-
tutes a further example of the opportunities of mesoporous
MCM-41 materials not only as acids but as oxidizing cata-
lysts in organic synthesis for the production of bulky fine
chemicals
catalyst (entries 17 and 18, Table 1). The secondary nature
of these by-products was established by following their evol-
ution with the reaction time (Figure 4) and by carrying out
a test reaction starting with pure binaphthol where the same
by-products were produced.
Although the formation of by-products in the oxidative
coupling of naphthol using CuSO /Al O had been pre-
4
2
3
[
25]
viously reported,
their chemical structure had not not
disclosed. We carried out chromatographic isolation of
these two products and their structures were assigned to
Experimental Section
(
2,8Ј);(8,2Ј)-dioxo-1,1Ј-binaphthyl (DOB) and dinaph-
Catalysts ؊ Preparation of CuSO
ina or Silica: Neutral alumina (Merck) or silica (Degussa Aerosil
00, 100% SiO ) (10 g) were added to a solution of CuSO · 5 H
1.56 g) or Fe(NO · 9 H O (2.52 g) in distilled water (100 mL)
and the suspension stirred at room temperature for 30 min. The
4 3 3
or Fe(NO ) Adsorbed on Alum-
1
tho[2,1-b:1Ј,2Ј-d]furan (DNF) based on their MS, H-NMR
and 13C-NMR spectroscopic and analytical data (see Ex-
perimental Section). Compound DOB would be the overox-
idized product of binaphthol, while DNF can be rational-
2
2
4
2
O
(
3
)
3
2
ized as the dehydration product of binaphthol. Analogous water was evacuated at 80°C under reduced pressure. The resulting
attack of the OH group of one naphthol group to the 2Ј moist solid was finally dried under vacuum at 150°C for 8 h.
1918
Eur. J. Org. Chem. 1999, 1915Ϫ1920

A Highly Selective Synthesis of 1,1Ј-Bi-2-naphthol by Oxidative Coupling
FULL PAPER
Preparation of Fe3؉- and Cu2؉-Exchanged Y Zeolite and MCM-41
Purification of the reaction mixtures and product isolation was ac-
complished by column chromatography (silica gel Merck) using a
Aluminosilicate: The initial NaY (Si/Al ϭ 2.6, unit cell size 24.65
˚
A) was a commercial sample (PQ Industries, CBV-100). MCM-41 1:1 mixture hexane-dichloromethane as eluent. 2,2Ј-Dinaphthyl
was synthesized by using amorphous silica (Degussa Aerosil 200)
and a 25% aqueous solution of tetramethylammonium hydroxide
ether was identified by comparison with an authentic commercial
sample (TCI America).
and hexadecyltrimethylammonium bromide as templates following
Spectroscopic Data of the Reaction By-products: Dinaphtho[2,1-
the procedure reported in the literature.[
27][40]
The Si/Al ratio deter-
b:1Ј,2Ј-d]furan (DNF):[
38][45] 1
H NMR δ: 9.20Ϫ9.15 (d, 2 H, J ϭ
ϭ 1,2; J ϭ 8,1 Hz), 8.00Ϫ7.95 (d,
H, J ϭ 8.7 Hz); 7.88Ϫ7.83 (d, 2 H, J ϭ 9 Hz), 7.80Ϫ7.72 (td, 2
ϭ 6,9; J ϭ 1,5 Hz); 7.64Ϫ7.56 (td, 2 H, J ϭ 7,2; J
,5 Hz). Ϫ High-resolution mass spectrum, calcd. for C20
mined by chemical analysis was 15, while the pore size distribution
8
2
.4 Hz), 8.11Ϫ8.06 (dd, 2 H, J
1
2
˚
measured by Ar adsorption were 35 and 50 A for two different
samples. The ion exchange was carried out starting fom NaY or
MCM-41 (0.7 g) using aqueous solutions (200 mL) of
Cu(CH COO) · H O (0.4 g) or Fe(NO ) · 9 H O (0.8 g). The sus-
3 2 2 3 3 2
pensions were stirred at room temperature for 24 h. The resulting
solids were filtered, washed, dried, and calcined at 500°C.
H, J
1
1
2
1
2
ϭ
12
H O
ϩ
m/z 268.0834, found 268.0837. MS: 268(25) [M ], 239(100),
19(89).
1
46][47]
IR (cmϪ1): 2940,
(
1
2,8Ј);(8,2Ј)-Dioxo-1,1Ј-binaphthyl (DOB):[
ϩ
Acid zeolite HY was prepared from NaY by exhaustive Na -to-
1
100, 780, 700, 620. Ϫ H NMR δ: 7.31 (d, 1 H, J ϭ 9 Hz), 7.10
ϩ
NH
4
4
ion exchange using NH AcO solutions and subsequent cal-
(
d, 1 H, J ϭ 4.8 Hz), 7.08 (d, 1 H, J ϭ 3.6 Hz), 6.92 (d, 1 H, J ϭ
[41]
cination as previously described.
2
The final Na O content meas-
13
9
Hz), 6.65 (dd, 1 H, J
CDCl , 75 MHz) δ: 108.6; 117.3; 120.0; 126.3; 127.1. Ϫ High-reso-
lution mass spectrum, calcd. for C20 m/z 282.0680, found
82.0687. MS: 282(100) [M ], 253(4), 224(6), 141(18).
1 2
ϭ 3.9 Hz; J ϭ 3.9 Hz). Ϫ C NMR
ured by atomic absorption spectroscopy was less than 0.05 wt-%.
(
3
XRD established that the crystallinity of the Cu2ϩ and Fe3ϩ-ex-
10 2
H O
ϩ
2
changed Y zeolites was 85% of that of the original NaY. This loss
of crystallinity indicates a partial framework dealumination of
NaY during the calcination steps and is well-documented in the
[
29][42]
literature.
In the case of ion-exchanged MCM-41 the number
Acknowledgments
of counts of the most characteristic XRD at 2θ ϭ 2.4° decreased
to 40% after ion doping.[43] This significant diminution in the XRD
Financial support by the Spanish D.G.I.C.Y.T. (Grant MAT97-
034-CO2) is gratefully acknowledged. E. A. also thanks to the
1
intensity of the doped MCM-41 with respect to the original sample
can be attributed to a decrease in the long-range order of the alumi-
nosilicate structure. Comparison of the isothermal Ar adsorption/
desorption measurements with that of the original as-synthesized
MCM-41 showed that the mesoporosity of the material was main-
tained after ion exchange. The new values of BET area of ion-
Spanish Ministry of Education for a scholarship. We are grateful
to Mrs. R. Torrero for recording the IR spectra.
[1]
G. Rosini, L. Franzini, A. Raffaelli, P. Salvadori, Synthesis
1
992, 503.
2
Ϫ1
[2]
exchanged MCM-41 were 750 m ϫ g , only slightly smaller than
J. Bao, W. D. Wulff, A. L. Rheingold, J. Am. Chem. Soc. 1993,
115, 3814.
3]
2
Ϫ1
those of the initial calcined MCM-41 (820 m ϫ g ) and the typi-
cal pattern of the isotherms for mesoporous material maintained.
It has been reported in the literature that the decrease of the XRD
intensity of MCM-41 may not be related to a massive destruction
[
R. Noyori, H. Takaya, Acc. Chem. Res. 1990, 23, 345.
H.-U. Blaser, Chem. Rev. 1992, 92, 935.
[4]
[5]
G. Kaupp, Angew. Chem., Int. Ed. Engl. 1994, 33, 728.
D. Seebach, R. Dahindeu, R. E. Marti, A. K. Beck, D. A.
Platther, F. N. M. Kuhnle, J. Org. Chem. 1995, 60, 1788.
S. Kobayashi, H. Ishitani, J. Am. Chem. Soc. 1994, 116, 4083.
M. Terada, Y. Motoyana, K. Mikami, Tetrahedron Lett. 1994,
[6]
of the porous structure.[
44]
[
7]
8]
[
Reaction Procedure: Previously dehydrated (for zeolites: 500°C,
overnight; for alumina and silica 200°C for 2 h under 1 Torr) cata-
lyst (350 mg) was added to a chlorobenzene solution (20 mL) of 2-
naphthol (100 mg). Nitrobenzene (100 mg) was added as internal
standard. The reactions were carried out in the presence of air,
oxygen, or in an autoclave as indicated in Table 1 for each run. The
resulting suspension was magnetically stirred at 140°C. The course
of the reaction was periodically followed by analyzing the organic
phase using a HP 5890 gas chromatograph equipped with a 25 m
capillary column of 5% phenylmethylsilicone. At the end of the
reaction (8 h), the catalyst was filtered and submitted to exhaustive
solidϪliquid extraction using a micro-Soxhlet equipment and di-
chloromethane as the solvent. The extracted solid catalyst was ana-
lysed by FT-IR and thermogravimetric-analysis differential-scan-
ning calorimetry (Netzsch-STA 409 EP thermobalance under air
stream using kaolin as inert standard).
3
5, 6693.
[9]
E. M. Carreira, W. Lee, R. A. Singer, J. Am. Chem. Soc. 1995,
117, 3649.
[
10]
11]
12]
13]
K. Maruoka, T. Itoh, T. Shirasaka, M. Yamamoto, J. Am.
Chem. Soc. 1988, 110, 310.
[
[
[
M. Shibasaki, H. Sasai, T. Arai, Angew. Chem., Int. Ed. Engl.
1
997, 36, 1237Ϫ1256.
R. Noyori, I. Tomino, M. Nishizana, J. Am. Chem. Soc. 1984,
106, 6709.
M. Periasamy, J. V. B. Kanth, C. K. Reddy, J. Chem. Soc., Per-
kin Trans. I 1995, 427.
[14]
G. D. Y. Sogah, D. J. Cram, J. Am. Chem. Soc. 1979, 101, 3035.
K. Ishihara, M. Kaneeda, H. Yamamoto, J. Am. Chem. Soc.
1994, 116, 11179.
[15]
[
[
16]
17]
T. Nakano, D. Y. Sogah, J. Am. Chem. Soc. 1995, 117, 534.
R. Pummerer, A. Rieche, E. Prell, Chem. Ber. 1926, 59, 2159.
M. J. S. Dewar, T. Nakaya, J. Am. Chem. Soc. 1968, 90, 7134.
D. Kuiling, W. Yang, Z. Lijun, W. Yangjie, Tetrahedron 1996,
52, 1005.
[18]
[
[
[
19]
20]
21]
H. Yamamoto, H. Fukushima, Y. Okamoto, K. Hatada, M.
Nakazaki, J. Chem. Soc., Chem. Commun. 1984, 1111.
B. Feringa, H. Wynbery, Bioorg. Chem. 1978, 7, 397.
F. Toda, K. Tanaka, S. Iwata, J. Org. Chem. 1989, 54,
The organic phases (from the reaction and the catalyst extraction)
were separately concentrated under vacuum, weighed, and analysed
by gas chromatography (GC), gas chromatographyϪmass spec-
[22]
3
007Ϫ3009.
[
23]
24]
trometry (CG-MS) (Varian Saturn II, same column and conditions
M. Smrcina, J. Polakova, S. Vyskocil, P. Kocovsky, J. Org.
Chem. 1993, 58, 4534.
1
as CG), H-NMR spectroscopy (Varian Geminis, 300 MHz, CDCl
3
[
M. Noji, M. Nakajima, K. Koga, Tetrahedron Lett. 1994, 35,
as solvent, TMS as internal standard), and GC-FT-IR (HP 5890
gas chromatograph, same column as GC-MS, coupled with a FT-
IR HP 5965A detector).
7
983Ϫ7984.
[25]
T. Sakamoto, H. Yonehara, C. Pac, J. Org. Chem. 1994, 59,
6859Ϫ6861.
Eur. J. Org. Chem. 1999, 1915Ϫ1920
1919

E. Armengol, A. Corma, H. Garc ´ı a, J. Primo
FULL PAPER
[
26]
[37]
[38]
M. Nakajima, K. Kanayama, I. Miyoshi, S. Hashimoto, Tetra-
hedron Lett. 1995, 36, 9519Ϫ9520.
S. R. Kirby, C. Song, H. H. Schobert, Catal. Today 1996, 31,
121Ϫ135.
[
27]
J. S. Beck, J. C. Vartuli, W. J. Roth, M. E. Leonowicz, C. T.
Kresge, K. D. Schmitt, Chu,T.-W. C. D. H. Olson, E. W. Shep-
pard, S. B. McCullen, J. B. Higgins, J. L. Schlenker, J. Am.
Chem. Soc. 1992, 114, 10834.
A. Arienti, F. Bigi, R. Maggi, P. Moggi, M. Rastelli, G. Sartori,
A. Trer e´ , J. Chem. Soc., Perkin Trans. 1 1997, 9, 1391Ϫ1393.
S. Yijian, W. Peter, J. Chem. Soc., Chem. Commun. 1997, 273.
A. Corma, V. Forn e´ s, M. T. Navarro, J. P e´ rez-Pariente, J.Catal.
1994, 148, 569.
[
[
39]
40]
[
[
[
[
[
28]
29]
30]
31]
32]
P. B. Venuto, Microporous Mater. 1994, 2, 297.
A. Corma, Chem. Rev. 1995, 95, 559Ϫ614.
[41]
[42]
A. Corma, H. Garc ´ı a, S. Iborra, J. Primo, J. Catal. 1989, 120,
78Ϫ87.
A. Corma, Chem. Rev. 1997, 97, 2373Ϫ2419.
A. Corma, H. Garc ´ı a, Catal. Today 1997, 38, 257Ϫ308.
W. M. Meier, D. H. Olson, Atlas of Zeolite Structure Types;
Butterworths: London, 1992.
J. K. Thomas, H. He, J. Klinowski, J. Am. Chem. Soc. 1994,
116, 11811Ϫ11818.
[43]
X. S. Zhao, F. Audslei, G. Q. Lu, J. Phys. Chem. B 1998, 102,
4143Ϫ4146.
[
[
33]
34]
C. T. Kresge, M. E. Leonowicz, W. J. Roth, J. C. Vartuli, J. S.
Beck, Nature 1992, 359, 710.
[44]
I. Kinski, H. Gies, F. Marlow, Zeolites 1997, 19, 373Ϫ381.
D. Fabbri, A. Dore, S. Gladiali, O. De Lucchi, G. Valle, Gazz.
Chim. Ital. 1996, 126, 11Ϫ18.
[45]
46]
For related examples of ship-in-a-bottle synthesis of organic
compounds wherein the key step is the formation of new CϪC
bonds see the following two references.
[
G. R. Clemo, R. Spence, J. Chem. Soc. 1928, 2811.
G. M. Guseva, B. N. Kolokolov, R. A. Khmelnitskii, Zh. Org.
Khim. 1980, 16, 141Ϫ146.
[
[
35]
36]
[47]
A. Sanju a´ n, M. Alvaro, G. Aguirre, H. Garc ´ı a, J. C. Scaiano,
J. Am. Chem. Soc. 1998, 120, 7351Ϫ7352.
F. Algarra, M. A. Esteves, V. Forn e´ s, H. Garc ´ı a, J. Primo, New
J. Chem. 1998, 333Ϫ338.
Received February 2, 1999
[O99046]
1920
Eur. J. Org. Chem. 1999, 1915Ϫ1920