Catalytic synergism in a C;inf;60;/inf;IL;inf;10;/inf;TEMPO;inf;2;/inf; hybrid in the efficient oxidation of alcohols

Article abstract of DOI:10.1002/adsc.201400641

A novel fullerene [5:1]hexakisadduct bearing two 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) radicals and ten 1-propyl-3-methylimidazolium bromide moieties has been synthesized and characterized. Such an C;inf;60;/inf;IL;inf;10;/inf;TEMPO;inf;2;/inf; hybrid has been successfully employed as a catalyst in the selective oxidation of a wide series of alcohols and is highly active at just 0.1 mol% loading. Moreover, it can be easily recovered by adsorption onto a multilayered covalently-linked SILP phase (mlc-SILP) through a "release and catch" approach and reused for up to 12 cycles without loss in efficiency. Interestingly, a catalytic synergistic effect of TEMPO and imidazolium bromide moieties combined in the same hybrid has been clearly shown.

Full text of DOI:10.1002/adsc.201400641

COMMUNICATIONS
DOI: 10.1002/adsc.201400641
Catalytic Synergism in a C60IL10TEMPO2 Hybrid in the Efficient
Oxidation of Alcohols
Hazi Ahmad Beejapur,a Vincenzo Campisciano,a Francesco Giacalone,a,*
and Michelangelo Gruttadauriaa,*
a
Dipartimento di Scienze e Tecnologie Biologiche, Chimiche e Farmaceutiche (STEBICEF) Sezione di Chimica, Universitꢀ
di Palermo, Viale delle Scienze s/n, Ed. 17, I-90128 Palermo, Italy
Fax : (+39)-091-596-825; phone: (+39)-091-238-97530; e-mail: francesco.giacalone@unipa.it or
michelangelo.gruttadauria@unipa.it
Received: July 2, 2014; Revised: September 2, 2014; Published online: && &&, 0000
Supporting information for this article is available on the WWW under http://dx.doi.org/10.1002/adsc.201400641.
Abstract: A novel fullerene [5:1]hexakisadduct
bearing two 2,2,6,6-tetramethylpiperidine 1-oxyl
(TEMPO) radicals and ten 1-propyl-3-methylimida-
zolium bromide moieties has been synthesized and
characterized. Such an C60IL10TEMPO2 hybrid has
been successfully employed as a catalyst in the se-
lective oxidation of a wide series of alcohols and is
highly active at just 0.1 mol% loading. Moreover, it
can be easily recovered by adsorption onto a multi-
layered covalently-linked SILP phase (mlc-SILP)
through a “release and catch” approach and reused
for up to 12 cycles without loss in efficiency. Inter-
estingly, a catalytic synergistic effect of TEMPO
and imidazolium bromide moieties combined in the
same hybrid has been clearly shown.
makes reactions slower than in the case of their ho-
mogeneous counterparts.[7] In this regard, very recent-
ly a new approach called “release and catch” has
been highlighted.[8] In this strategy, the catalytic
system is non-covalently immobilized on the support,
but the catalytic moiety is released in solution over
the course of the reaction and it is recaptured at the
end of the reaction. In such a manner, the benefits of
homogeneous (high catalytic activity and reaction
rates) and heterogeneous catalysis (easy separation
and recycling) are combined. Interestingly, the “re-
lease and catch” approach has found application in
organometallic-based catalysts,[9] organocatalysts[10]
and metal-based catalysts.[11] In the past few years, we
have been engaged in the use of silica-supported ionic
liquid-like phase monolayers (SILLP) and multilayers
(mlc-SILP) as reversible catalyst reservoirs. Both
kinds of materials were excellently employed for or-
ganocatalyst recovery and recycling[10,12] as well as in
Keywords: alcohols; fullerene; ionic liquids; oxida-
tion; TEMPO; 2,2,6,6-tetramethylpiperidine 1-oxyl
(TEMPO)
À
the immobilization of Pd nanoparticles for C C cou-
pling processes in batch[13] and in flow.[14] On the
other hand, we started exploring new recyclable
TEMPO-based systems: 10 mol% of ionic liquid-
In the last decades TEMPO-like catalysts have tagged TEMPO derivatives were easily recovered
emerged as powerful, metal-free and environmentally with the help of mlc-SILP and recycled in up to 13
sustainable alternatives in the oxidation of primary consecutive cycles with no loss in activity,[12d] whilst
and secondary alcohols to the corresponding carbonyl a series of fullerene-TEMPO derivatives with two,
compounds.[1] Nevertheless, their high price prompted four and twelve TEMPO moieties can be quickly re-
scientists examine the development of supported covered through a short pad of silica and recycled for
TEMPO catalysts in order to obtain recyclable mate- seven times.[15] With this background, we decided to
rials. Hence, TEMPO has been covalently immobi- explore the possibility to use the tridimensional
lized onto various supports such as silica,[2] magnetic [60]fullerene sphere as a molecular platform for com-
nanoparticles,[3] soluble[4] and insoluble[5] organic poly- bining the catalytic effect of two different components
mers, and carbon nanotubes.[6]
in the same molecule and if their close proximity
However, although several of these materials were would enhance the catalytic activity. Moreover, we
catalytically active and easily recyclable, they often planned to design a molecule in which the presence
suffer from the inherent drawback of heterogeneous of ionic liquid tags would increase the compatibility
catalysis, namely the reduced mass transfer that between the final catalyst and our mlc-SILP materials.
Adv. Synth. Catal. 0000, 000, 0 – 0
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
Hazi Ahmad Beejapur et al.
Scheme 1. Synthesis of the C60IL10TEMPO2 hybrid (4).
The choice of IL is strategic since the proper counter- adduct
3
in 44% yield. Finally, the desired
anion may exert a catalytic role in the oxidation pro- C60IL10TEMPO2 4 hybrid has been obtained in almost
cess. In this regard, we considered the bromide ions quantitative yield by treatment of 3 with N-methyl-
to be a good candidate given their widely recognized
ACHTUNGTRENiNUNG midazole. The presence of paramagnetic TEMPO
role in TEMPO-mediated Anelli oxidations,[16] as well moieties prevents the collection of valuable structural
as in combination with hypervalent iodine(III) re- information by NMR spectroscopy. However, even
agents.[17] The presence of 30 equivalent double bonds though H NMR spectra of 3 and 4 have very low res-
in C60 makes this carbon allotrope a good candidate olution, some assignments can be made. The H NMR
1
1
for multiple consecutive additions. Recently, some spectrum of 4 shows the signals of the methylenic
C60-TEMPO systems have been prepared through groups, as well as two signals of imidazolium moieties
Prato,[18] Bamford–Stevens,[19] or Bingel synthetic pro- (the acid C-2 proton disappears after exchange with
tocols.[20] In our case, we chose the Bingel–Hirsch pro- the deuterated solvent) and that of the methyl groups
tocol[21] in order to prepare the fullerene monoadduct (Supporting Information, Figure S1). The octahedral
1[22] which has been used as starting derivative in the substitution pattern of the C60 cage simplifies the
synthesis of the C60IL10TEMPO2 4 hybrid (Scheme 1). 13C NMR spectra of 3 and 4 (Suppporting Informa-
Bingel reaction of 1 with 8 equivalents of bis(3-bro- tion, Figures S2 and S3), giving rise to two sp2 signals
mopropyl) malonate 2 afforded the [5:1]hexakis in the 147–139 ppm range along with an sp3 signal at
2
asc.wiley-vch.de
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 0000, 000, 0 – 0
ÝÝ
These are not the final page numbers!

COMMUNICATIONS
Catalytic Synergism in a C60IL10TEMPO2 Hybrid
Table 1. Optimization of oxidation conditions and catalyst
loading.
hand, complete conversions in very short reaction
time (40 min) were obtained with just 0.1 mol% of
C60IL10TEMPO2 when BAIB in DCM was used (en-
tries 6 and 7). These promising results prompted us to
decrease the catalyst loading (entries 8–10).
Interestingly, 0.05 mol% of 4 are able to quantita-
tively oxidize 1-phenylethanol within 2 h with a turn-
over number (TON) of 2000 (entry 8). Higher TONs
can be achieved by further decreasing the catalyst
content down to 0.01 mol% albeit with incomplete
conversions.
Hence, we checked the substrate scope of the reac-
tion employing catalyst C60IL10TEMPO2 at 0.1 mol%
in the oxidation of a wide range of substrates
(Table 2). Primary benzylic alcohols, such as benzyl,
Entry
Conditions
Loading
[%]
Time
[h]
Yield
[%]
TON
1[a]
2[a]
3[b]
4[b]
5[b]
6[c]
7[c]
8[c]
9[c]
10[c]
NaClO
NaClO
O2/TBN
O2/TBN
0.1
0.5
0.1
0.5
1.0
0.1
0.1
0.05
0.02
0.01
6.0
2.0
4.0
4.0
8.0
0.7
0.7
2.0
22.0
22.0
75
>95
15
50
91
>95
>95
>95
52
750
200
150
100
O2/TBN
91
BAIB/0.4[d]
BAIB/1.6[d]
BAIB/1.6[d]
BAIB/1.6[d]
BAIB/1.6[d]
1000
1000
2000
2600
3000
30
Table 2. Catalytic oxidation of primary and secondary alco-
hols with C60IL10TEMPO2 (4).[a]
[a]
Reaction conditions: alcohol (0.8 mmol), 3M NaClO
(2.86 mL), 0.5M KBr (0.16 mL), NaHCO3 (1.28 mmol),
CH2Cl2 (2 mL), 0–158C.
[b]
[c]
[d]
Reaction
conditions:
alcohol
(0.8 mmol),
TBN
(15 mol%), O2 (balloon), water (0.5 mL), 508C.
Entry Substrate
Product
Time
[h]
Yield
[%]
Reaction conditions: alcohol (0.8 mmol), BAIB
(1.1 equiv.), CH2Cl2, room temperature.
Substrate concentration in mol·LÀ1.
1
2
0.7
1.0
>95
>95
ca. 70 ppm and the carbonyl at 162–164 ppm. Howev-
er, in none of the spectra are the signals due to the
paramagnetic TEMPO moieties discernable.
3
4
5
1.0
1.0
5.0
>95
>95
>95
The FT-IR spectra of 3 and 4 systems clearly show
the presence of the carbonyl stretching in 1742–
À1
À
1746 cm range along with that of N OC radicals at
1463 cmÀ1 (Supporting Information, Figures S4 and
S5). Finally, high resolution APCI-MS confirmed the
proposed hexakis-adduct structure for 3 revealing the
presence of relevant peaks at m/z=2850 (M+), at
m/z=2678 (M+ÀTEMPO) and at m/z=2506
(M+À2TEMPO) (Supporting Information, Figure S6).
Unfortunately, due to its highly charged nature we
were not able to obtain a good mass spectrum of 4.
Hence, we tested catalyst 4 by applying three differ-
ent conditions in which the co-oxidant has been
varied for the oxidation of 1-phenylethanol to aceto-
phenone: sodium hypochlorite solution (commercial
bleach) in the presence of KBr and NaHCO3 for ad-
justing the pH (Anelliꢂs conditions),[16] oxygen in the
presence of tert-butyl nitrite (TBN) as co-catalyst,[23]
and hypervalent iodine(III) [bis(acetoxy)iodo]ben-
zene (BAIB).[24] The results are collected in Table 1
and show that with NaClO as terminal oxidant
0.5 mol% of 4 are needed to fully convert 1-phenyl-
6[b]
1.0
2.0
>95
>95
7[b,c]
8[c]
9
3.0
1.0
3.0
>95
>95
>95
10[c]
11[b,c]
12[b,c]
4.0
>95
8.0
>95
13
1.5
5.0
1.5
>95
>95
>95
14[c]
15
[a]
ACHTUNGTRENNUNGethanol in 2 h (entry 2). When oxygen has been em-
Reaction conditions: alcohol (0.8 mmol), BAIB
(1.1 equiv.), CH2Cl2, room temperature.
0.5 mol% of catalyst 4.
ployed (entries 3–5) the catalyst loading had to be in-
creased up to 1 mol% in order to get good conversion
but with a rather long reaction time. On the other
[b]
[c]
1.3 equiv. of BAIB.
Adv. Synth. Catal. 0000, 000, 0 – 0
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
3
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
Hazi Ahmad Beejapur et al.
Figure 1. Catalyst recycling through “release and catch”.
para-bromobenzyl, para-nitrobenzyl and p-methoxy-
Finally, also primary aliphatic alcohols were trans-
benzyl alcohols were quantitatively converted in formed with excellent yields within 1.5–5 h (en-
40 min (entries 1–4) whereas 2-naphthalenemethanol tries 13–15). Interestingly, in all cases, primary alco-
required 5 h (entry 5). Secondary benzylic alcohols hols afforded the corresponding aldehydes selectively
such as 1-indanol and benzoin were quantitatively without undergoing the easy autoxidation to the re-
converted but needed 0.5 mol% of 4 (entries 6 and 7) spective carboxylic acid[25] probably due to the ability
whilst diphenylmethanol gave benzophenone in of TEMPO systems to act as free radical scavengers,
>95% yield in 3 h (entry 8). Cyclohexanol was com- and hence as an autoxidation inhibitor.[26]
pletely oxidized in 40 min (entry 9) whereas 1-Boc-4-
Then we applied the “release and catch” approach
hydroxypiperidine and acyclic secondary alcohols for the recycling of C60IL10TEMPO2 using mlc-SILP
such as 2-decanol and 4-phenylbutan-2-ol (entries 10– 5. Once the first cycle was complete, support 5 was
12) required longer reaction times for quantitative added and the solvent removed under reduced pres-
conversions.
sure causing the adsorption (catch) of the catalyst
(Figure 1). Afterwards, the final product was extract-
4
asc.wiley-vch.de
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 0000, 000, 0 – 0
ÝÝ
These are not the final page numbers!

COMMUNICATIONS
Catalytic Synergism in a C60IL10TEMPO2 Hybrid
Figure 2. Recycling of C60IL10TEMPO2 (4) (1.0 and
0.1 mol%) in the formation of acetophenone.
ed by using a proper solvent (diethyl ether) that does
not dissolve the adsorbed catalyst. Hence, the solid
catalytic material filtered off (support+catalyst) acts
as a catalyst reservoir and can be employed in the
next cycles with CH2Cl2, a solvent in which catalyst 4
is soluble and can be released in solution. In that way,
1 mol% of C60IL10TEMPO2 4 was recycled for 12 runs
Figure 3. Chemical structure of C60IL12 (6).
whilst 0.1 mol% were used in four consecutive reac- ploying the fullerene monoadduct 1, support 5, and
tions (Figure 2). In the first case, after 9 cycles with the symmetric hexakisadduct C60IL12 6 (Figure 3).[27]
complete conversion, in the 10th run the yield dropped
The results are summarized in Table 3. First, a com-
to 70%. Hence, the catalyst was separated from the parison between monoadduct 1 and catalyst 4 shows
support and used alone in the 11th cycle giving rise to the important role of the imidazolium bromide moiet-
94% of conversion. Thus, in order to confirm a detri- ies in the catalytic activity (Table 3 entry 1 vs. 1st cycle
mental effect of the support (probably damaged after 1 mol% in Figure 2). It is noteworthy that when
10 cycles) a new cycle with the used mlc-SILP has monoACTHUNRGTNENUGadduct 1 or C60IL12 6 are employed separately in
been carried out yielding 54% of conversion. As 1 and 5 mol%, respectively (the same amount present
a whole, the catalytic system operated with a TON in 1 mol% of 4), just 10 and 38% yields are obtained
>1100. Beside the damage experienced by the sup- (entries 1 and 2), which summed give 48% vs. >95%
port after 10 cycles, the procedure still remains an obtained with 4 in the 1st cycle. However, a sensible
easy approach to smoothly and quantitatively recover
the catalyst with no need for its heterogeneization. In
this regard, the catalyst cannot be easily recovered by
simple filtration since it is employed in such a little
Table 3. Effect of each catalytic moiety on the oxidation of
1-phenylethanol.[a]
amount and big percentages get lost during recovery.
Less recyclable runs resulted with 0.1 mol% given
that in the 4th cycle just 12% of acetophenone was iso-
lated. In this case, due to the low amount of catalyst
employed, even small losses for leaching during the
recycling procedure have a big effect on the efficien-
cy. However, given the small amounts used, the over-
all TON was >2500.
As stated before, bromide ions may have a role in
the oxidation of alcohols[17b] and this may have a domi-
nant part during the recycles due to the presence of
additional BrÀ present in the mlc-SILP 5. In order to
discern how the TEMPO moieties and bromide ions
(distinguishing those present in catalyst 4 and those
proceeding from support 5) contribute to the oxida-
tion process, a series of blank tests was conducted em-
Entry
Catalyst
Loading [mol%]
Yield [%]
1
2
3
4
5
6
7
C60TEMPO2 (1)
C60IL12 (6)
1+6
mlc-SILP (5)
C60TEMPO2 (1)
C60IL12 (6)
1+6
1.0
5.0
10
38
93
34
8
1.0+5.0
[b]
–
0.1
0.5
0.1+0.5
4
36
[a]
Reaction conditions: alcohol (0.8 mmol), BAIB
(1.1 equiv.), CH2Cl2 2 mL, room temperature, 40 min.
60 mg, i.e., the amount used in the recycling experiments.
[b]
Adv. Synth. Catal. 0000, 000, 0 – 0
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
5
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
Hazi Ahmad Beejapur et al.
increase in conversion is achieved when the two cata-
lysts are combined (entry 3) evidencing a kind of co-
operation between them. As expected, also the sup-
port 5 displayed some catalytic activity affording 34%
of acetophenone after 40 min (entry 4). Nevertheless,
during the recycling, taking into account the sum of
the three different contributions, we reach a value of
82%, lower than that obtained with the release and
catch system (>95%). Such a synergistic effect is
even more pronounced when the catalyst loading is
reduced to 0.1 mol% for 1 and 0.5 mol% for 6 (en-
tries 5 and 6). In this case the sum of the yields
achieved with the two different catalysts reaches 12%
whereas their combination 36% (entry 7), three times
more but very far from the quantitative yield ob-
tained with 0.1 mol% of C60IL10TEMPO2 (Table 1,
entry 6).
Scheme 2. Oxidation of alcohols catalyzed by bromide ions
in the presence of BAIB.
On the other hand, no beneficial effects have been
observed when other terminal oxidants such as TBN
or NaClO are employed. In the former case, after 8 h
of reaction with 1 mol% of catalyst, 1 gave 86%yield
vs. 91% obtained with 4. Under Anelliꢂs conditions,
0.1 mol% of 1 after 6 h gave acetophenone quantita-
tively,[15] whilst 4 afforded just 75% yield (Table 1,
entry 1).
Scheme 3. Synergic effect in the C60IL10TEMPO2 catalyst.
The mechanism of bromide ion promotion in the
TEMPO/BAIB-mediated alcohol oxidation could be mechanistic studies are currently in progress in our
explained as follows. The formation of a certain laboratory and will be reported in due course.
amount of carbonyl compound in the absence of
In conclusion, a new C60IL10TEMPO2 [5:1]hexaki-
TEMPO (see Table 3) could be ascribed to the reac- sadducts hybrid has been synthesized and used as cat-
tion of bromide ions of the imidazolium-based fuller- alyst in the oxidation of primary and secondary alco-
ene (or the imidazolium-based support) with [bis(ace- hols to carbonyl compounds. This molecule showed
toxy)iodo]benzene which may afford bis(acyloxy)bro- an outstanding catalytic activity even with low load-
mate(I) anions 7 (Scheme 2). It has been assumed ings and it was easily recovered through the “release
that the supported bis(acyloxy)bromate(I) anion is and catch” approach employing an mlc-SILP as rever-
not an active oxidant but rather the acylated hypobro- sible support. In such a way up to 11 cycles have been
mite 8,[28] which can be released in solution.[29] Proton carried out with almost no loss in catalytic activity.
exchange between 9 and HBr will give the starting The analysis of the single parts of the catalyst evi-
bromide-based material.
denced
a
high
synergistic
effect
in
the
The intriguing high synergism probably has its C60IL10TEMPO2 system, probably due to the close
origin from the close spatial proximity of TEMPO proximity of TEMPO and BrÀ moieties that act as
and BrÀ that act as a concentrated phase in which the a highly concentrated phase.
two catalysts are “confined”, resulting in a better oxi-
dation activity than the individual components. More
precisely, what we suppose is that the spatial proximi-
Experimental Section
ty of [Br(OAc)2]À species to the reduced TEMPO
species (TEMPOH) strongly favors the regeneration
of the oxoammonium salt (Scheme 3). Then, the
[Br(OAc)2]À species may play a dual role: (i) regener-
ation of the oxammonium species, via the acylated hy-
pobromite 8 and (ii) direct oxidation of the alcohol.
Such a dual role in a confined space will increase the
catalytic efficiency of the whole system.
General Procedures for the Oxidations
Oxidation with oxygen: A mixture of alcohol (0.8 mmol),
tert-butyl nitrite (15 mol%), and catalyst 4 in H2O (0.5 mL)
was prepared in a single-necked round-bottom flask. The
flask was then filled with pure oxygen (balloon), and the re-
sulting mixture was stirred at 508C, under an oxygen atmos-
phere. After the time indicated in Table 1, the reaction mix-
ture was cooled down to room temperature, and Et2O (3ꢃ
5 mL) was added. The mixture was stirred for 5 min, the or-
ganic layers were separated and dried over anhydrous
Moreover, different oxidation mechanisms may op-
erate simultaneously given that the activity of
TEMPO/BrÀ,[16] BAIB/BrÀ,[17] and TEMPO/BAIB[24]
pairs is well recognized. In this regard, more detailed Na2SO4. The solvent was removed under reduced pressure
6
asc.wiley-vch.de
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 0000, 000, 0 – 0
ÝÝ
These are not the final page numbers!

COMMUNICATIONS
Catalytic Synergism in a C60IL10TEMPO2 Hybrid
to give the crude product which was purified by simple fil-
tration with a pad of silica (AcOEt/petroleum ether). The
conversion of the product was calculated by H NMR after
d) B. Karimi, A. Biglari, J. H. Clark, V. Budarin,
Angew. Chem. 2007, 119, 7348–7351; Angew. Chem. Int.
Ed. 2007, 46, 7210–7213; e) B. Karimi, E. Badreh, Org.
Biomol. Chem. 2011, 9, 4194–4198.
1
careful determination of its weight.
Oxidation with NaClO (Anelli): A mixture of alcohol
(0.8 mmol), catalyst 4 and 0.16 mL of aqueous KBr (0.5M)
in 2 mL CH2Cl2 was prepared in a single-necked flask. The
mixture was cooled to 08C, followed by the addition of
2.86 mL of NaOCl (0.35M), and the solution was buffered
to pH 8.6 with NaHCO3 (108 mg). The biphasic reaction
mixture was stirred vigorously, and the temperature of the
solution was maintained between 0–158C until total con-
sumption of the starting alcohol on TLC. Then, the solution
was diluted with CH2Cl2 (3ꢃ10 mL), the organic layer was
separated by extraction and dried over anhydrous Na2SO4.
The solvent was removed under reduced pressure to give
the crude compound, which contained the catalyst and the
carbonyl compound. The crude compound was further puri-
fied by simple filtration with a pad of silica and the conver-
[3] a) A. Schꢄtz, R. N. Grass, W. J. Stark, O. Reiser, Chem.
Eur. J. 2008, 14, 8262–8266; b) A. K. Tucker-Schwartz,
R. L. Garrell, Chem. Eur. J. 2010, 16, 12718–12726;
c) B. Karimi, E. Farhangi, Chem. Eur. J. 2011, 17, 6056–
6060; d) B. Karimi, E. Farhangi, Adv. Synth. Catal.
2013, 355, 508–516; e) Z. Zheng, J. Wang, M. Zhang, L.
Xu, J. Ji, ChemCatChem 2013, 5, 307–312.
[4] a) M. Benaglia, A. Puglisi, O. Holczknecht, S. Quici, G.
Pozzi, Tetrahedron 2005, 61, 12058–12064; b) C. X.
Miao, L. N. He, J. Q. Wang, J. Gao, Synlett 2009, 3291–
3294.
[5] a) A. Dijksman, I. W. C. E. Arends, R. A. Sheldon,
Chem. Commun. 2000, 271–272; b) C. Tanyeli, A.
Gꢅmꢅs¸, Tetrahedron Lett. 2003, 44, 1639–1642; c) M.
Gilhespy, M. Lok, X. Baucherel, Catal. Today 2006,
117, 114–119.
[6] a) J. P. Lindner, C. Roben, A. Studer, M. Stasiak, R.
Ronge, A. Greiner, H. J. Wendorff, Angew. Chem.
2009, 121, 9035–9038; Angew. Chem. Int. Ed. 2009, 48,
8874–8877; b) Y. Wang, X. Song, S. Shao, H. Zhong, F.
Lin, RSC Adv. 2012, 2, 7693–7698.
1
sion of the product was calculated by H NMR after careful
determination of its weight.
Oxidation with BAIB: [Bis(acetoxy)iodo]benzene
(0.88 mmol) was added to a solution of alcohol (0.8 mmol)
and catalyst 4 in 2 mL CH2Cl2. The reaction mixture was
stirred at room temperature and monitored by TLC. After
the time indicated in Table 1, the solvent was removed
under reduced pressure to afford the crude product which
was purified by simple filtration with a pad of silica
(AcOEt/petroleum ether) and the conversion of the product
[7] a) G. Oehme, Comprehensive Asymmetric Catalysis,
Springer, Heidelberg, Berling, 1999, Vol. 3, pp 1377–
1386; b) D. E. DeVos, B. F. Sels, P. A. Jacobs, Adv.
Catal. 2001, 46, 1–87; c) J. A. Gladysz, Pure Appl.
Chem. 2001, 73, 1319–1324.
1
was calculated by H NMR after careful determination of its
weight.
[8] M. Gruttadauria, F. Giacalone, R. Noto, Green Chem.
Details for catalyst preparation and for the recycling ex-
periments can be found in the Supporting Information.
2013, 15, 2608–2618.
[9] a) S. Wittmann, A. Schꢄtz, R. N. Grass, W. J. Stark, O.
Reiser, Angew. Chem. 2010, 122, 1911–1914; Angew.
Chem. Int. Ed. 2010, 49, 1867–1870; b) C. Vriamont, M.
Devillers, O. Riant, S. Hermans, Chem. Eur. J. 2013, 19,
12009–12017.
Acknowledgements
Financial support from the University of Palermo and COST
Action CM0905 ORCA are gratefully acknowledged. Mass
spectra were provided by Centro Grandi Apparecchiature –
UniNetLab – Universitꢀ di Palermo funded by P.O.R. Sicilia
2000–2006, Misura 3.15 Quota Regionale.
[10] E. Montroni, M. Lombardo, A. Quintavalla, C. Trombi-
ni, M. Gruttadauria, F. Giacalone, ChemCatChem 2012,
4, 1000–1006.
[11] a) M. I. Burguete, E. Garcꢆa-Verdugo, I. Garcia-Villar,
F. Gelat, P. Licence, S. V. Luis, V. Sans, J. Catal. 2010,
269, 150–160; b) F. Zhao, B. M. Bhanage, M. Shirai, M.
Arai, Chem. Eur. J. 2000, 6, 843–848; c) K. Kçhler, W.
Kleist, S. S. Prçckl, Inorg. Chem. 2007, 46, 1876–1883;
d) N. T. S. Phan, M. Van Der Sluys, C. W. Jones, Adv.
Synth. Catal. 2006, 348, 609–679; e) J. D. Webb, S. Mac-
Quarrie, K. McEleney, C. M. Crudden, J. Catal. 2007,
252, 97–109; f) S. MacQuarrie, J. H. Horton, J. Barnes,
K. McEleney, H.-P. Loock, C. M. Crudden, Angew.
Chem. 2008, 120, 3324–3328; Angew. Chem. Int. Ed.
2008, 47, 3279–3282; g) J. M. Richardson, C. W. Jones,
J. Catal. 2007, 251, 80–93.
[12] a) M. Gruttadauria, S. Riela, P. Lo Meo, F. D’Anna, R.
Noto, Tetrahedron Lett. 2004, 45, 6113–6116; b) M.
Gruttadauria, S. Riela, C. Aprile, P. Lo Meo, F.
D’Anna, R. Noto, Adv. Synth. Catal. 2006, 348, 82–92;
c) C. Aprile, F. Giacalone, M. Gruttadauria, A. M. Mar-
culescu, R. Noto, J. D. Revell, H. Wennemers, Green
Chem. 2007, 9, 1328–1334; d) H. A. Beejapur, F. Giac-
alone, R. Noto, P. Franchi, M. Lucarini, M. Gruttadau-
ria, ChemCatChem 2013, 5, 2991–2999.
References
[1] a) M. Zhao, J. Li, E. Mano, Z. Song, D. M. Tschaen,
E. J. J. Grabowski, P. J. Reider, J. Org. Chem. 1999, 64,
2564–2566; b) R. A. Sheldon, I. W. C. E. Arends,
G. J. T. Brink, A. Dijksman, Acc. Chem. Res. 2002, 35,
774–781; c) P. Gamez, I. W. C. E. Arends, R. A. Shel-
don, J. Reedijk, Adv. Synth. Catal. 2004, 346, 805–811;
d) R. Liu, X. Liang, C. Dong, X. Hu, J. Am. Chem.
Soc. 2004, 126, 4112–4113; e) R. A. Sheldon, I. W. C. E.
Arends, Adv. Synth. Catal. 2004, 346, 1051–1071; f) M.
Shibuya, M. Tomizawa, I. Suzuki, Y. Iwabuchi, J. Am.
Chem. Soc. 2006, 128, 8412–8413.
[2] a) T. Dohi, K. I. Fukushima, T. Kamitanaka, K. Mori-
moto, N. Takenaga, Y. Kita, Green Chem. 2012, 14,
1493–1501; b) C. Bolm, F. Thomas, Chem. Commun.
1999, 1795–1796; c) T. Fey, H. Fischer, S. Bachmann, K.
Albert, C. Bolm, J. Org. Chem. 2001, 66, 8154–8159;
Adv. Synth. Catal. 0000, 000, 0 – 0
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
7
ÞÞ
These are not the final page numbers!

COMMUNICATIONS
Hazi Ahmad Beejapur et al.
[13] a) M. Gruttadauria, L. F. Liotta, A. M. P. Salvo, F.
Giacalone, V. La Parola, C. Aprile, R. Noto, Adv.
Synth. Catal. 2011, 353, 2119–2130; b) R. Buscemi, F.
Giacalone, S. Orecchio, M. Gruttadauria, ChemPlu-
sChem 2014, 79, 421–426; c) C. Pavia, F. Giacalone,
L. A. Bivona, A. M. P. Salvo, C. Petrucci, G. Strappa-
veccia, L. Vaccaro, C. Aprile, M. Gruttadauria, J. Mol.
Catal. A: Chem. 2014, 387, 57–62.
[14] C. Pavia, E. Ballerini, L. A. Bivona, F. Giacalone, C.
Aprile, L. Vaccaro, M. Gruttadauria, Adv. Synth. Catal.
2013, 355, 2007–2018.
[15] H. A. Beejapur, V. Campisciano, P. Franchi, M. Lucari-
ni, F. Giacalone, M. Gruttadauria, ChemCatChem 2014,
6, 2419–2424.
[16] a) P. L. Anelli, S. Banfi, F. Montanari, S. Quici, J. Org.
Chem. 1989, 54, 2970–2972; b) P. L. Anelli, C. Biffi, F.
Montanari, S. Quici, J. Org. Chem. 1987, 52, 2559–2562.
[17] a) H. Tohma, S. Takizawa, T. Maegawa, Y. Kita,
Angew. Chem. 2000, 112, 1362–1364; Angew. Chem.
Int. Ed. 2000, 39, 1306–1308; b) W. Qian, E. Jin, W.
Bao, Y. Zhang, Angew. Chem. 2005, 117, 974–977;
Angew. Chem. Int. Ed. 2005, 44, 952–955.
[18] a) Y. Li, Z. Mao, J. Xu, J. Yang, Z. Guo, D. Zhu, J. Li,
B. Yin, Chem. Phys. Lett. 1997, 265, 361–364; b) A. Po-
limeno, M. Zerbetto, L. Franco, M. Maggini, C. Corva-
ja, J. Am. Chem. Soc. 2006, 128, 4734–4741; c) C. Cor-
vaja, M. Maggini, M. Prato, G. Scorrano, M. Venzin, J.
Am. Chem. Soc. 1995, 117, 8857–8858; d) F. Arena, F.
Bullo, F. Conti, C. Corvaja, M. Maggini, M. Prato, G.
Scorrano, J. Am. Chem. Soc. 1997, 119, 789–795; e) Y.
Li, X. Lei, S. Jockusch, J. Y. C. Chen, M. Frunzi, J. A.
Johnson, R. G. Lawler, Y. Murata, M. Murata, K. Ko-
matsu, N. J. Turro, J. Am. Chem. Soc. 2010, 132, 4042–
4043; f) S. Campestrini, C. Corvaja, M. De Nardi, C.
Ducati, L. Franco, M. Maggini, M. Meneghetti, E.
Menna, G. Ruaro, Small 2008, 4, 350–356.
nozuka, T. Nogami, M. Kubota, M. Ohashi, Tetrahe-
dron 1996, 52, 5103–5112; d) P. Ceroni, F. Conti, C.
Corvaja, M. Maggini, F. Paolucci, S. Roffia, G. Scorra-
no, A. Toffoletti, J. Phys. Chem. A 2000, 104, 156–163.
[20] a) L. Franco, M. Mazzoni, C. Corvaja, V. P. Gubskaya,
L. Berezhnaya, I. A. Nuretdinov, Chem. Commun.
2005, 2128–2130; b) V. P. Gubskaya, L. S. Berezhnaya,
V. V. Yanilkin, V. I. Morozov, N. V. Nastapova, Y. Y.
Efremov, I. A. Nuretdinov, Russ. Chem. Bull. 2005, 54,
1642–1655.
[21] a) C. Bingel, Chem. Ber. 1993, 126, 1957–1959; b) I.
Lamparth, A. Hirsch, J. Chem. Soc. Chem. Commun.
1994, 1727–1728.
[22] V. P. Gubskaya, L. S. Berezhnaya, A. T. Gubaidullin,
I. I. Faingold, R. A. Kotelnikova, N. P. Konovalova,
V. I. Morozov, I. A. Litvinov, I. A. Nuretdinov, Org.
Biomol. Chem. 2007, 5, 976–981.
[23] B. Karimi, E. Farhangi, Chem. Eur. J. 2011, 17, 6056–
6060.
[24] a) A. De Mico, R. Margarita, L. Parlanti, A. Vescovi,
G. Piancatelli, J. Org. Chem. 1997, 62, 6974–6977; b) O.
Holczknecht, M. Cavazzini, S. Quici, I. Shepperson, G.
Pozzi, Adv. Synth. Catal. 2005, 347, 677–688; c) J. S.
Yadav, N. N. Yadav, T. S. Rao, B. V. S. Reddy, A. Al
Khazim Al Ghamdi, Eur. J. Org. Chem. 2011, 2011,
4603–4608.
[25] R. A. Sheldon, J. K. Kochi, Metal-catalyzed oxidations
of organic compounds, Academic Press, New York,
1981.
[26] a) R. A. Sheldon, I. W. C. E. Arends, Adv. Synth. Catal.
2004, 346, 1051–1071; b) R. A. Sheldon, I. W. C. E.
Arends, J. Mol. Catal. A: Chem. 2006, 251, 200–214.
[27] See the Supporting Information for the synthesis and
characterization of 6 as well as: V. Campisciano, V.
La Parola, L. F. Liotta, F. Giacolone, M. Gruttadauria,
Chem. Eur. J. 2015, DOI: 10.1002/chem.201406067.
[28] R. Ben-Daniel, P. Alsters, R. Neumann, J. Org. Chem.
2001, 66, 8650–8653.
[19] a) K. Matsuda, G. Ulrich, H. Iwamura, J. Chem. Soc.
Perkin Trans. 2 1998, 1581–1588; b) T. Ishida, K. Shino-
zuka, M. Kubota, M. Ohashi, T. Nogami, J. Chem. Soc.
Chem. Commun. 1995, 1841–1842; c) T. Ishida, K. Shi-
[29] M. Brꢅnjes, G. Sourkouni-Argirusi, A. Kirschning, Adv.
Synth. Catal. 2003, 345, 635–642.
8
asc.wiley-vch.de
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Adv. Synth. Catal. 0000, 000, 0 – 0
ÝÝ
These are not the final page numbers!

COMMUNICATIONS
Catalytic Synergism in a C60IL10TEMPO2 Hybrid in the
Efficient Oxidation of Alcohols
9
Adv. Synth. Catal. 2014, 356, 1 – 9
Hazi Ahmad Beejapur, Vincenzo Campisciano,
Francesco Giacalone,* Michelangelo Gruttadauria*
Adv. Synth. Catal. 0000, 000, 0 – 0
ꢁ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
9
ÞÞ
These are not the final page numbers!