Acyloxylation of 1,4-Dioxanes and 1,4-Dithianes Catalyzed by a Copper-Iron Mixed Oxide

Article abstract of DOI:10.1021/acs.joc.5b01043

The use of a copper-iron mixed oxide as a heterogeneous catalyst for the efficient synthesis of α-acyloxy-1,4-dioxanes and 1,4-dithianes employing t-butyl peroxyesters is reported. The preparation and characterization of the catalyst are described. The ef

Full text of DOI:10.1021/acs.joc.5b01043

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Article
Acyloxylation of 1,4-dioxanes and 1,4-
dithianes catalyzed by a copper-iron mixed oxide
Ana Leticia García-Cabeza, Rubén Marín-Barrios, F. Javier Moreno-Dorado, María J. Ortega,
Hilario Vidal, Jose Manuel Gatica, Guillermo M. Massanet, and Francisco Miguel Guerra
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.5b01043 • Publication Date (Web): 02 Jun 2015
Downloaded from http://pubs.acs.org on June 7, 2015
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Acyloxylation of 1,4-dioxanes and 1,4-dithianes catalyzed by a copper-iron mixed oxide
Ana Leticia García-Cabeza,a Rubén Marín-Barrios,a F. Javier Moreno-Dorado,a María J. Ortega,a
Hilario Vidal,b José M. Gatica,b Guillermo M. Massaneta and Francisco M. Guerra*,a
aDepartamento de Química Orgánica, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto
Real, Cádiz, Spain
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bDepartamento de Ciencia de los Materiales e Ingeniería Metalúrgica y Química Inorgánica,
Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
*francisco.guerra@uca.es
ABSTRACT: The use of a copper-iron mixed oxide as a heterogeneous catalyst for the efficient
synthesis of -acyloxy- 1,4-dioxanes and 1,4-dithianes employing t-butyl peroxyesters is reported.
The preparation and characterization of the catalyst are described. The effect of the heteroatoms
and a plausible mechanism are discussed. The method is operationally simple and involves low-
cost starting materials affording products in good to excellent yields.
INTRODUCTION
The direct activation of C-H bonds has experienced a significant progress in the field of organic
synthesis in the last decade.1 This kind of transformation poses important challenges such as
overcoming the inert nature of most C-H bonds or the control of site selectivity.2 Some substrates,
however, present the appropriate features for a successful C-H activation. The introduction of a
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new oxygenated functional group at sp3 C-H located  to an ethereal oxygen is feasible due the
relatively weak dissociation energy of this type of bonds.3 Recently, the preparation of -acyloxy
ethers has been the subject of study by the Fu and Yuan group4 and the Patel group.5
In contrast, the preparation of their -acyloxy thioethers siblings has received scarce attention. In
1982, Szarek and Hronowsky reported the preparation of 1,4-dithian-2-yl benzoate in 26% yield,
as an intermediate in the preparation of new pyrimidine nucleoside analogues with improved
antitumor activity as surrogates of 5-fluorouracil (5-FUra).6 To the best of our knowledge no other
-acyloxy dithiane has been prepared.
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Scheme 1. Preparation of pyrimidine nucleosides by Szarek and Hronowsky.
Previous reports oriented to the synthesis of -acyloxy ethers have based their success in the use
of transition-metal catalysts, such as Cu7 and Fe8 or by the employment of TBAI9 or NCS10
(Scheme 2a). Copper and iron are considered as low-risk metals in terms of supply and toxicity,11
which represents an advantage over other metals such as those belonging to the platinum group. In
this article, we present the use of a copper-iron mixed oxide (CuFeOx henceforth), which
effectively catalyses the introduction of an acyloxy group  to the oxygen or sulfur atoms in 1,4-
dioxanes and 1,4-dithianes (Scheme 2b).
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Scheme 2. Preparation of 1,4-dioxane and 1,4-dithiane benzoates.
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Although mixed oxides have proved to be of help in catalysis of oxidation reactions,12 their use
in the field of organic synthesis has been rather limited. Recently, we have reported the allylic
oxidation of alkenes and the γ-hydroxylation of enones by employing a copper-aluminum mixed
oxide.13 This approach permits the synergistic action of two different metal centres over a substrate.
Moreover, it allows the heterogeneization of a process usually performed in homogeneous way.
RESULTS AND DISCUSSION
The preparation was carried out following our method for the synthesis of a copper-aluminum
mixed oxide (for details about preparation and characterisation of the catalyst see Supporting
Information).13b,14 To ensure the reproducibility of the CuFeOx preparation, it was submitted to a
characterization process. Observation by SEM revealed that the catalyst presented the form of a
fine powder, with some irregularities in morphology and size, but in general consisting of micron-
sized well-rounded grains. This study was complemented by granulometric measurements, which
showed a distribution particle size in volume with relative maxima at approx. 0.8, 9 and 40 μm,
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that fitted quite well with the size of the particles observed by SEM. In addition, a textural study
was performed using N2 physisorption that indicated the mesoporous character of the solid.
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Figure 1. Typical scanning electron micrograph of the CuFeOx catalyst.The raw X-ray
diffraction diagram of the sample showed the presence of crystalline CuO, tenorite phase.
However, the use of Rietveld analysis allowed detecting other phases such as copper
hydroxycarbonates (malachite and azurite) and spinel CuFe2O4 mixed oxide. The relatively lower
intensity of iron-containing phases can be reasonably related to the intrinsic limitations of the XRD
technique, which prevent from detecting amorphous phases (the synthesis method followed does
not favour obtaining crystalline materials) and underestimate iron-related phases due to the well-
known Cu Kα absorption effect of this element.
There was a good agreement between compositional analysis data obtained by ICP, XRF and
EDS, so indicating the homogeneity of the sample both at massive and micron-surface levels
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(Table 1). Moreover, they are relatively consistent with the Cu/Fe atomic ratio selected for catalyst
preparation and the formation of a copper-iron mixed oxide.
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Table 1. Compositional analysis (wt.%) of the CuFeOx sample by means of induced coupled
plasma spectroscopy, X-ray fluorescence and energy-dispersive X-ray spectroscopy
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Technique
ICP
Cu
47.1±0.3
51.5
Fe
17.2±0.1
22.4
O
not applicable
24.0
XRF
EDSa
52.7±3.0
18.1±1.5
22.2
aData correspond to the average of values obtained for four different areas analysed in spot
mode.
Once the catalyst was characterized, we focused on the reaction of 1,4-dioxane 1 either with
benzaldehyde 3 or benzoic acid 5, using TBHP as the oxidant. The yields were moderate, affording
the corresponding benzoyloxy 1,4-dioxane 4 in 35% and 31% yield, respectively (Table 2, entries
a and b).
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Table 2. Preliminary assaysa,b
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aReaction conditions: 1,4-dioxane 1 (5.0 mmol), CuFeOx (30 mg, 8.9 mol% Cu), CH3CN (2
mL), 140 ºC, 24 h. (a) Benzaldehyde 3 (2.5 mmol), TBHP (70% aqueous, 7.5 mmol). (b) Benzoic
acid 5 (2.5 mmol), TBHP (70% aqueous, 7.5 mmol). (c) Benzaldehyde 3 (2.5 mmol), TBHP (70%
aqueous, 7.5 mmol), TBAI (0.5 mmol). (d) TBPB 6 (2.5 mmol). bGC yield.
Recently, Wan et al have demonstrated that treatment of an aldehyde with TBAI and TBHP
leads to the corresponding peroxyester that is in situ used as an oxidant in a Kharasch-Sosnovsky
oxidation of an olefin.15 In our case, the treatment of 1,4-dioxane 1 and benzaldehyde 3 with TBAI
in the presence of CuFeOx was negative, leading only to a mere 5% yield (Table 2, entry c).
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However, when we employed t-butyl peroxybenzoate (TBPB) as the oxidant, the reaction
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proceeded quantitatively (Table 2, entry d).
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To assess the efficiency of CuFeOx as a catalyst, various copper sources were subsequently
tested in our benchmark reaction shown in Table 3. It was observed that in the absence of CuFeOx
(entry 1), the product 4 was formed in only 4% yield. The use of Cu(OAc)2·H2O (entry 3) resulted
in 44% yield, and the mixture of CuFeOx precursors, CuCl2 and FeCl3·6H2O (entry 4) provided
65% yield. Other commercial oxides and chlorides, such as Cu2O, CuO, CuCl2, and FeCl3·6H2O
(entries 5-8) were also tested, producing the desired product in moderate yields. Entries 2 and 9-11
confirm the important role of the temperature, displaying a dramatic drop of yield below 100 ºC.
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Given that the use of TBPB 6 conducted to the desired α-benzoyloxy 1,4-dioxane 4 in
quantitative yield, we thought that the use of different peroxyesters would allow us to prepare
different -acyloxy ethers.
Table 3. Search for the optimal catalyst.a
Entry
1
catalyst
-
CuFeOx
Cu(OAc)2·H2O
CuCl2 + FeCl3H2O
Cu2O
Yieldi (%)
4
100
44
65
72
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4d
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6c
CuO
CuCl2
FeCl36H2O
CuFeOx
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10b,g
11b,h
CuFeOx
CuFeOx
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aReaction conditions: 1,4-dioxane 1 (5.0 mmol), TBPB 6 (2.5 mmol), CH3CN (2 mL), 140 ºC, 24 h.
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c
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bCatalyst (30 mg, 8.9 mol% Cu, 3.7 mol% Fe). Catalyst (8.9 mol% Cu). CuCl2 (17 mg) and
FeCl36H2O (13 mg). eCatalyst (3.7 mol% Fe). f80 ºC. g100 ºC. h120 ºC. iDetermined by GC.
The above-mentioned report by Wan et al describes a facile preparation of t-butyl peroxyesters
from aldehydes catalyzed by TBAI.15 This methodology was found to be very reproducible, robust,
and suited for our purposes. Thus, we proceeded to the preparation of different peroxyesters that
were reacted with 1,4-dioxane 1 in the presence of CuFeOx (Table 4). Gratifyingly, the reaction of
aromatic peroxyesteres furnished the corresponding -aryl esters 7-10 in good yields. The nature
of the group attached to the aromatic ring of the peroxyester seemed not to affect the outcome,
providing good yields either in the presence of donor or acceptor groups. The use of lineal t-butyl
peroxyesters was also possible, as demonstrated by the formation of 1,4-dioxan-2-yl octanoate 11.
The use of t-butyl 2-thienylperoxycarboxylate led to the corresponding ester 12 in a good 73%
yield. A 1-naphthyl group could be introduced in the starting peroxyester providing the desired
product 13 in 52% yield. An interesting case was that of the peroxyester prepared from
cinnamaldehyde, that underwent a coupling reaction with a concomitant decarboxylative process
furnishing 1,4-dioxane derivative 14. This kind of transformation has been previously reported by
Li16 and Han17 groups in processes catalized by CuO and Fe(acac)3, respectively.
The exploration of the scope continued with 1,4-dithiane 2. Its behavior was parallel to that
already described for 1,4-dioxane 1. Thus, the respective aryl esters 15-19 were prepared with good
to excellent yields. The yields of 20 and 21 were nevertheless significantly lower than those of 11
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and 12. The naphthyl derivative 22 was obtained in 53% yield, a value similar to that obtained for
13. The main difference was observed in the treatment with the cinnamic acid peroxyester, where
the decarboxylation was not observed, and the expected acyloxylated 1,4-dithiane 23 was produced
in 26% yield.
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Table 4. Scope of 1,4-dioxane and 1,4-dithiane derivatives.a,b
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aReaction conditions: 1,4-dioxane 1 (5.0 mmol) or 1,4-dithiane 2 (2.0 mmol), peroxyester (2.5
mmol for 4 and 6-14 or 1.0 mmmol for 15-23), CuFeOx (30 mg, 8.9 mol% Cu for 4 and 6-14 or
12 mg, 8.9 mol% Cu for 15-23), CH3CN (2 mL) for 4 and 6-14 or CH3CN (1 mL) and CH2Cl2 (1
mL) for 15-23, 140 ºC, 24 h. bGC yield (yield).
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A general inspection of Table 4 indicates that the presence of two heteroatoms, either sulfur or
oxygen, provides a suitable system for the acyloxylation reaction to take place. We found
convenient to evaluate the behaviour of substrates bearing just one heteroatom. The results are
displayed in Table 5. Cyclic ethers such as tetrahydropyran 24 and tetrahydrofuran 25 led only to
traces of the corresponding benzoyloxy esters. Additionally, linear butyl methyl ether 26 provided
the regioisomers 35a and 35b in a poor 23% overall yield (in a 1:3.6 ratio). A slightly better yield
(30%) was obtained when a linear substrate bearing two oxygen atoms in 1,4-relative positions 27
was used. These results suggest that the presence of two oxygen atoms favors the reaction.
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Table 5. Role of the substitution pattern in the ether or thioether.a,b
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aReaction conditions: ethers 24-30 (5.0 mmol), tetrahydrothiophene 31 (2.0 mmol) or 1,4-
oxathiane 32 (5.0 mmol) and TBPB (2.5 mmol for 24-30 and 32 or 1.0 mmmol for 31), CuFeOx
(30 mg, 8.9 mol% Cu for 24-30 and 32 or 12 mg, 8.9 mol% Cu for 31), CH3CN (2 mL) for 24-30
or CH3CN (1 mL) and CH2Cl2 (1 mL) for 31 and 32, 140 ºC, 24 h. bGC yield (yield). c35a and 35b
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d
formed in the same reaction (23% overall yield). 39a-39c formed in the same reaction (66%
overall yield). e41a and 41b formed in the same reaction (70% overall yield).
The importance of the relative location of the oxygen atoms was further investigated (Table 5).
Although 1,3-dioxane 28 and 1,3-dioxolane 29 performed poorly, 2-methyl-1,3-dioxolane 30
furnished compounds 39a-39c in an overall yield of 66% (in a 13:2.5:1 ratio). This fact could be
explained in terms of relative stability of 29 and 30 (the acetals of formaldehyde and acetaldehyde,
respectively) under the reaction conditions. Additionally, the tertiary nature of the resulting radical
intermediate (vide infra) involved in the formation of 39a explains this result. Eventually, it is
required the presence of two oxygen atoms, preferably in a 1,4-relative position, for the reaction to
proceed properly. It is noteworthy that, in contrast to tetrahydrofuran 25, tetrahydrothiophene 31
produced 40 in 46% yield. This seems to be in accordance with the higher activating ability of the
sulfur atom.18 This idea was supported by the fact that 1,4-oxathiane 32 underwent the
acyloxylation mainly at the α-position of the sulfur atom, leading to 41a and 41b in a 3.7:1 ratio
(70% overall yield).
The radical nature of the mechanism was confirmed with a control reaction, employing 1,4-
dioxane 1 as substrate and TBPB as the oxidant in the presence of 2,6-di-t-butyl-4-methylphenol
(BHT), which led to the formation of 4 in just 2 % yield.
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Although CuFeOx presents a multicomponent nature which makes difficult to precise the origin
of its activity, there are precedents of the use of copper-iron mixed oxides such as CuFe2O4 in
heterogeneous conditions in oxidative couplings.19 A proposal of a plausible mechanism is depicted
in Scheme 3. Decomposition of TBPB can be favored by the presence of the metallic centers (A).
The solid provides a surface suitable for the formation of radicals and the encounter of the different
species (B). The presence of the t-butoxyl radical would induce the formation of the radical at the
-position of the ether or thiother (C). The higher yields obtained when two heteroatoms are
present in the ether or the thioether suggest the coordination of one of these heteroatoms to a
metallic center. The other oxygen or sulfur atom would activate its contiguous position by electron
donation to the * orbital of the C-H bond.20 The possibility of backbonding from the metal to the
sulfur atom21 would explain that one sulfur atom is enough for the reaction to proceed in contrast
to when only one oxygen atom is present. Once the radical is formed, the coupling with the acyloxy
moiety would take place, affording the corresponding product (D).
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Scheme 3. Plausible mechanism
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CONCLUSION
This work is an interesting example of the use of mixed oxides as catalysts for the activation of
C-H bonds. In particular, the acyloxylation at the α-position of ethers and thioethers can be
performed employing copper-iron mixed oxides in an efficient and clean way. In addition, there
are limited precedents of the use of organic peroxides in heterogeneous catalysis.22 On the other
hand, although the acyloxylation of 1,4-ethers has recently been subject of study, the use of the
related 1,4-thioethers has not been reported, with the exception of Szarek and Hrownosky paper.
Last but not least important, the presence of sulfur atoms in a substrate generally restricts the use
of metallic catalysts due to catalyst poisoning.23 This fact limits the application of C-H activation
reactions in the search of sulfur-based heterocyclic drugs. In this sense, the use of copper-iron
mixed oxides provides an efficient alternative to overcome this problem.
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EXPERIMENTAL SECTION
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General Information. NMR spectra were recorded on 400 MHz or 500 MHz spectrometers
using standard pulse sequences. Spectra were referenced to the internal chloroform (CHCl3,  =
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7.25 ppm for 1H-NMR,  = 77.0 ppm for 13C-NMR). GC analyses were performed using a DB-5
column. Octadecane was employed as internal standard and analyses were run in triplicate.
Reactions were monitored through TLC on commercial silica gel plates precoated with silica gel.
Visualization of the developed plate was performed by fluorescence quenching and aqueous ceric
ammonium molybdate or anisaldehyde stains. HPLC purification was carried out using a 1×25 cm
silica gel column (10 m particle size). Fourier Transform Infrared Spectroscopy (FTIR) spectra
were recorded using NaCl plates and data are reported in cm-1. Mass spectra were recorded on a
UPLC-QTOF mass spectrometer.
Compositional analysis of the copper-iron mixed oxide was studied by means of both
inductively coupled plasma atomic emission spectroscopy (ICP-AES) and X-Ray fluorescence
(XRF). Textural characteristics were investigated by means of N2 physisorption at -196 ºC. The
experiment was performed with a sample which was first subjected to a heating treatment under
high vacuum at 150 ºC for 2 h. The recorded isotherms were used to obtain the specific surface
area, SBET, and the porosity using the BET and BJH data treatment, respectively. Scanning electron
microscopy (SEM) images and energy dispersive spectroscopy (EDS) compositional data were
obtained with a scanning electron microscope using a nominal resolution of 3 nm. Particle size
distribution was obtained employing a granulometer operating with laser diffraction over a
previously centrifuged dispersion of the sample (3 min sonicated) in water. Results were obtained
from the average of the three tests performed to ensure reproducibility of the measurements.
Structural study was carried out with X-ray diffraction (XRD) at room temperature using a powder
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diffractometer operating with Cu K radiation. The 2 angle ranged from 3º to 75º with a step of
0.05º and a counting time of 1 s. The Rietveld method was applied to the XRD data using the
FULLPROF program.24
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Catalyst Preparation.13b The preparation of the copper-iron mixed oxide (CuFeOx) was carried
out following our method for the synthesis of copper-aluminum mixed oxide, which is based on
that described by Guida et al14 for the synthesis of hydrotalcites. To this end, a solution of Na2CO3
(1.27 g) and NaOH (5.20 g) in water was added dropwise for 1.5 h over a solution containing CuCl2
(5.00 g) and FeCl3·6H2O (4.00 g) in water (50 mL). The suspension turned dark brown and it was
stirred at 70 ºC for 22 h. The mixture was then filtered and the precipitate washed with warm water
(3 × 200 mL). The solid was dried in an oven at 105 ºC for 24 h, after which time it was ground
until a fine powder was obtained. The solid was left exposed to air for 72 h prior to use.
General Procedure for the Synthesis of Peroxyesters. All peroxyesters have been prepared
according to the literature procedure.15 The following two peroxyesters have been
synthesized for the first time.
(E) t
-butyl 3-phenylprop-2-eneperoxoate. Colorless oil (894 mg, 20%); 1H NMR (400
MHz, CDCl3)

7.60 (d, J = 16.0 Hz, 1H), 7.36 (dd, J = 6.7, 2.9 Hz, 2H), 7.25

7.21 (m,
164.7,
max 3063, 2936, 2983, 1755,
3H), 6.27 (d, J = 16.0 Hz, 1H), 1.24 (s, 9H); C{1H}NMR (100 MHz, CDCl3)

13
145.5, 133.5, 130.3, 128.5, 127.7, 112.7, 83.1, 25.7; IR (film)
1634, 1450, 1367, 1190, 1108, 980, 763 cm-1; HRMS (ESI) calcd. for C13H16O3Na [M+Na]+
243.0997; found 243.0997.
1
t
-butyl octaneperoxoate. Colorless oil (804 mg, 18%); H NMR (400 MHz, CDCl3)

2.28 (t, J = 7.5 Hz, 2H), 1.64 (tt, J = 7.5, 7.5 Hz, 2H), 1.30 (s, 9H), 1.29
(t, J = 6.9 Hz, 3H); 13C{1H}NMR (100 MHz, CDCl3)
1.20 (m, 8H), 0.85

171.1, 83.2, 31.6, 31.3, 29.0, 28.8,
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26.1, 25.0, 22.5, 14.0; IR (film) 
max 2957, 2930, 2859, 1779, 1467, 1367, 1191, 854 cm-1;
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HRMS (ESI): calcd. for C8H15O3 [M-tBu]- 159.1021; found 159.1015.
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General Procedure for the Acyloxylation of Ethers and 1,4-Oxathiane. 30 mg of CuFeOx
was suspended in 2 mL of acetonitrile in a sealed tube and it was stirred for 5 min. Then,
ether (5.0 mmol) and t-butyl peroxyester (2.5 mmol) were added and the reaction mixture
was stirred at 140 ºC (Caution: a considerable pressure can be developed). After 24 h, an
aliquot was taken and analysed by GC (using octadecane as an internal standard). The
solvent was evaporated under reduced pressure and the crude was purified by SEPHADEX
column chromatography (methanol as an eluent). For 1,4-oxathiane, 2 mL of
acetonitrile/dichloromethane (1:1) was employed as a solvent.
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General Procedure for the Acyloxylation of Thioethers. 12 mg of CuFeOx was suspended
in 1 mL of acetonitrile in a sealed tube and it was stirred for 5 min. Then, thioether (2.0
mmol) and t-butyl peroxyester (1.0 mmol, dissolved in 1 mL of dichloromethane) were
added and the reaction mixture was stirred at 140 ºC (Caution: a considerable pressure can
be developed). After 24 h, an aliquot was taken and analysed by GC (using octadecane as
an internal standard). The solvent was evaporated under reduced pressure and the crude was
purified by silica gel column chromatography (mixtures of EtOAc/hexanes as eluents).
1,4-dioxan-2-yl benzoate (4). Colerless oil (380 mg, 73%); 1H NMR (500 MHz, CDCl3)  8.11
(d, J = 7.6 Hz, 2H), 7.58 (tt, J = 7.5, 1.8 Hz, 1H), 7.45 (dd, J = 7.9, 7.9 Hz, 2H), 6.09 (br s, 1H),
4.21 (ddd, J = 11.8, 6.6, 6.6 Hz, 1H), 3.893.87 (m, 2H), 3.833.80 (m, 2H), 3.66 (ddd, J = 5.2,
2.6, 2.6 Hz, 1H); 13C{1H}NMR (126 MHz, CDCl3)  165.2, 133.3, 129.9, 129.7, 128.4, 89.8, 67.8,
66.1, 61.7; IR (film) max 2973, 2858, 1731, 1601, 1453, 1259, 1155, 881, 711 cm-1; HRMS (ESI)
calcd. for C11H12O4Na [M+Na]+ 231.0633; found 231.0640.
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1,4-dioxan-2-yl 4-methylbenzoate (7). Yellowish oil (450 mg, 81%); H NMR (400 MHz,
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6
7
CDCl3)  8.00 (d, J = 8.1 Hz, 2H), 7.25 (d, J = 8.0 Hz, 2H), 6.07 (br s, 1H), 4.20 (ddd, J = 12.0,
8
9
6.5, 6.5 Hz, 1H), 3.893.86 (m, 2H), 3.833.79 (m, 2H), 3.66 (ddd, J = 5.3, 2.6, 2.6 Hz, 1H), 2.41
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(s, 3H); 13C{1H}NMR (100 MHz, CDCl3)  165.3, 144.2, 129.9, 129.1, 126.9, 89.6, 67.9, 66.1,
61.8, 21.7; IR (film) max 2974, 2857, 1726, 1612, 1277, 1087, 883, 754 cm-1; HRMS (ESI) calcd.
for C12H13O4 [M-H]- 221.0814; found 221.0818.
1,4-dioxan-2-yl 4-methoxybenzoate (8). White amorphous solid (506 mg, 85%); 1H NMR (400
MHz, CDCl3)  8.05 (d, J = 9.0 Hz, 2H), 6.91 (d, J = 9.0 Hz, 2H), 6.05 (br s, 1H), 4.18 (ddd, J =
11.8, 5.5, 5.5 Hz, 1H), 3.863.85 (m, 2H), 3.84 (s, 3H), 3.813.78 (m, 2H), 3.65 (ddd, J = 5.3,
2.7, 2.7 Hz, 1H); 13C{1H}NMR (100 MHz, CDCl3)  164.9, 163.7, 132.0, 122.0, 113.7, 89.5, 67.9,
66.1, 61.8, 55.4; IR (film) max 2972, 2856, 1720, 1607, 1512, 1257, 1170, 1088, 1020, 913, 883,
771 cm-1; HRMS (ESI) calcd. for C12H14O5Na [M+H]+ 261.0739; found 261.0736.
1,4-dioxan-2-yl 4-chlorobenzoate (9). White amorphous solid (504 mg, 83%); 1H NMR (400
MHz, CDCl3)  8.04 (d, J = 8.8 Hz, 2H), 7.42 (d, J = 8.8 Hz, 2H), 6.07 (br s, 1H), 4.19 (ddd, J =
11.8, 6.6, 6.6 Hz, 1H), 3.883.87 (m, 2H), 3.833.81 (m, 2H), 3.67 (ddd, J = 5.1, 2.6, 2.6 Hz, 1H);
13C{1H}NMR (100 MHz, CDCl3)  164.4, 139.9, 131.2, 128.8, 128.1, 90.0, 67.7, 66.1, 61.8; IR
(film) max 2960, 2856, 1718, 1594, 1236, 1152, 1087, 882, 758 cm-1; HRMS (ESI) calcd. for
35
37
C11H10O4 Cl [M-H]- 241.0268; found 241.0258, calcd. for C11H10O4 Cl [M-H]- 243.0238; found
243.0250.
1,4-dioxan-2-yl 4-bromobenzoate (10). White amorphous solid (567 mg, 79%); 1H NMR (400
MHz, CDCl3)  7.97 (d, J = 8.8 Hz, 2H), 7.59 (d, J = 8.8 Hz, 2H), 6.07 (br s, 1H), 4.19 (ddd, J =
13.3, 6.6, 6.6 Hz, 1H), 3.88
3.86 (m, 2H), 3.833.81 (m, 2H), 3.67 (ddd, J = 5.2, 2.6, 2.6 Hz, 1H);
13C{1H}NMR (100 MHz, CDCl3)  164.5, 131.8, 131.4, 128.6, 90.0, 67.8, 66.1, 61.8; IR (film)
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
max 2974, 2863, 1727, 1589, 1260, 1068, 880, 746 cm-1; HRMS (ESI) calcd. for C11H11O4 BrNa
5
6
81
[M+Na]+ 308.9738; found 308.9749, calcd. for C11H11O4 BrNa [M+Na]+ 310.9718; found
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308.9756.
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1,4-dioxan-2-yl octanoate (11). Yellow oil (294 mg, 51%); 1H NMR (400 MHz, CDCl3)  5.83
(br s, 1H), 4.08 (ddd, J = 12.3, 6.5, 6.5 Hz, 1H), 3.78

3.66 (m, 4H), 3.60 (ddd, J = 5.5, 2.8, 2.8
1.19 (m, 8H), 0.85 (t, J =
Hz, 1H), 2.36 (t, J = 7.6 Hz, 2H), 1.63 (tt, J = 14.5, 14.5 Hz, 3H), 1.31

6.7 Hz, 3H). 13C{1H}NMR (100 MHz, CDCl3)  172.5, 89.0, 67.7, 66.0, 61.7, 34.3, 31.6, 29.0,
28.8, 24.7, 22.5, 14.0. IR (film) max 2958, 2930, 2857, 1747, 1456, 1232, 1147, 1069, 917, 856,
756 cm-1; HRMS (ESI) calcd. for C12H21O4 [M-H]- 229.1440; found 229.1441.
1
1,4-dioxan-2-yl-thiophene-2-carboxylate (12). Yellow oil (391 mg, 73%); H NMR (400
MHz, CDCl3)  7.88 (dd, J = 3.8, 1.3 Hz, 1H), 7.59 (dd, J = 5.0, 1.3 Hz, 1H), 7.11 (dd, J = 5.0, 3.8
Hz, 1H), 6.04 (br s, 1H), 4.20 (ddd, J = 11.8, 7.1, 5.9 Hz, 1H), 3.863.85 (m, 2H), 3.813.79 (m,
2H), 3.65 (ddd, J = 5.3, 2.6, 2.6 Hz, 1H); 13C{1H}NMR (100 MHz, CDCl3)  160.8, 134.1, 133.2,
127.8, 89.9, 67.7, 66.0, 61.8; IR (film) max 3103, 2975, 2858, 1715, 1418, 1256, 1062, 1013, 909,
750 cm-1; HRMS (ESI) calcd. for C9H9O4S [M-H]- 213.0222; found 213.0226.
1
1,4-dioxan-2-yl 1-naphthoate (13). White amorphous solid (336 mg, 52%); H NMR (400
MHz, CDCl3)  9.02 (d, J = 8.7 Hz, 1H), 8.35 (dd, J = 7.3, 1.3 Hz, 1H), 8.04 (d, J = 8.2 Hz, 1H),
7.88 (d, J = 8.2 Hz, 1H), 7.63 (ddd, J = 8.4, 8.4, 1.4 Hz, 1H), 7.54 (ddd, J = 8.1, 6.9, 1.2 Hz, 1H),
7.51 (dd, J = 8.2, 7.4 Hz, 1H), 6.21 (br s, 1H), 4.26 (ddd, J = 11.8, 6.2, 6.2 Hz, 1H), 3.96
3.95 (m,
2H), 3.86

3.83 (m, 2H), 3.71 (ddd, J = 5.2, 2.6, 2.6 Hz, 1H); 13C{1H}NMR (100 MHz, CDCl3)
 165.8, 134.0, 133.8, 131.5, 130.9, 128.5, 128.0, 126.2, 126.1, 125.7, 124.4, 89.8, 67.9, 66.1, 61.8;
IR (film) max 2973, 2856, 1721, 1510, 1233, 1131, 1067, 883, 783 cm-1; HRMS (ESI): calcd. for
C15H13O4 [M-H]- 257.0814; found 257.0815.
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2-styryl-1,4-dioxane (14). Yellowish amorphous solid (128 mg, 27%); H NMR (500 MHz,
CDCl3)  7.38 (d, J = 7.1 Hz, 2H), 7.31 (t, J = 7.5 Hz, 2H), 7.25 (tt, J = 6.5, 1.3 Hz, 1H), 6.69 (d,
J = 16.1 Hz, 1H), 6.09 (dd, J = 16.1, 6.2 Hz, 1H), 4.25 (dddd, J = 10.1, 6.2, 2.8, 1.4 Hz, 1H),
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3.893.80 (m, 3H), 3.75 (br dd, J = 11.6, 2.6 Hz, 1H), 3.66 (ddd, J = 11.5, 10.8, 3.2 Hz, 1H), 3.42
(dd, J = 11.5, 10.0 Hz, 1H); 13C{1H}NMR (126 MHz, CDCl3)  136.3, 132.6, 128.5, 127.8, 126.5,
125.1, 76.0, 70.9, 66.6, 66.3; IR (film) max 3026, 2968, 2868, 1452, 1118, 967, 923, 870, 746, 695
cm-1; HRMS (ESI) calcd. for C12H15O2 [M+H]+ 191.1072; found 191.1079.
1
1,4-dithian-2-yl benzoate (15). Yellowish amorphous solid (192 mg, 80%); H NMR (400
MHz, CDCl3)  8.14 (dd, J = 8.4, 1.4 Hz, 2H), 7.58 (tt, J = 6.8, 1.3 Hz, 1H), 7.46 (dd, J = 7.8, 7.8
Hz, 2H), 6.06 (dd, J = 5.0, 1.9 Hz, 1H), 3.44
3.37 (m, 2H), 3.10 (dd, J = 11.7, 11.7 Hz, 1H), 3.01
(dd, J = 14.2, 5.1 Hz, 1H), 2.81

2.70 (m, 2H); 13C{1H}NMR (100 MHz, CDCl3)  164.9, 133.3,
129.8, 129.7, 128.4, 67.7, 33.5, 28.0, 26.2; IR (film) max 3063, 2911, 1721, 1601, 1451, 1324,
1265, 1095, 1069, 965, 917, 710 cm-1; HRMS (ESI): calcd. for C11H12O2S2Na [M+Na]+ 263.0176;
found 263.0145.
1,4-dithian-2-yl 4-methylbenzoate (16). White amorphous solid (226 mg, 89%); 1H NMR (500
MHz, CDCl3)  8.03 (d, J = 8.2 Hz, 2H), 7.26 (d, J = 7.9 Hz, 2H), 6.06 (br s, 1H), 3.41 (br s, 2H),
3.04 (br s, 2H), 2.77 (br s, 2H), 2.41 (s, 3H); 13C{1H}NMR (126 MHz, CDCl3):  165.0, 144.1,
129.9, 129.2, 127.1, 68.1, 38.7, 28.1, 23.0, 21.7; IR (film) max 2913, 1718, 1612, 1265, 1092, 914,
749 cm-1; HRMS (ESI) calcd. for C12H14O2S2Na [M+Na]+ 277.0333; found 277.0340.
1
1,4-dithian-2-yl 4-methoxybenzoate (17). White amorphous solid (224 mg, 83%); H NMR
(500 MHz, CDCl3)  8.09 (d, J = 9.0 Hz, 2H), 6.93 (d, J = 8.9 Hz, 2H), 6.04 (br d, J = 3.7 Hz, 1H),
3.85 (s, 3H), 3.42
3.37 (m, 2H), 3.102.98 (m, 2H), 2.79
2.72 (m, 2H); 13C{1H}NMR (126
MHz, CDCl3)  164.6, 163.7, 131.9, 122.1, 113.7, 67.6, 55.4, 33.6, 28.1, 26.3; IR (film) max 2913,
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2839, 1715, 1606, 1511, 1258, 1093, 1029, 967, 847, 769 cm-1; HRMS (ESI) calcd. for
C12H14O3S2Na [M+Na]+ 293.0282; found 293.0288.
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4
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8
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1,4-dithian-2-yl 4-chlorobenzoate (18). Yellowish amorphous solid (234 mg, 85%); 1H NMR
(500 MHz, CDCl3)  8.07 (d, J = 8.8 Hz, 2H), 7.43 (d, J = 8.8 Hz, 2H), 6.05 (br d, J = 4.9 Hz, 1H),
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3.443.37 (m, 2H), 3.10 (dd, J = 12.5, 12.5 Hz, 1H), 3.00 (dd, J = 14.2, 5.0 Hz, 1H), 2.812.71
(m, 2H); 13C{1H}NMR (126 MHz, CDCl3)  164.1, 139.8, 131.2, 128.8, 128.2, 68.1, 33.5, 28.1,
26.2; IR (film) max 2956, 2913, 1723, 1594, 1264, 1092, 1014, 964, 915, 757 cm-1; HRMS (ESI)
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37
calcd. for C11H11O2S2 ClNa [M+Na]+ 296.9787; found 296.9790, calcd. for C11H11O2S2 ClNa
[M+Na]+ 298.9757; found 298.9755.
1,4-dithian-2-yl 4-bromobenzoate (19). White amorphous solid (287 mg, 90%); 1H NMR (500
MHz, CDCl3)  8.00 (d, J = 8.7 Hz, 2H), 7.60 (d, J = 8.7 Hz, 2H), 6.05 (br d, J = 3.6 Hz, 1H),
3.423.37 (m, 2H), 3.152.93 (m, 2H), 2.87
2.73 (m, 2H); 13C{1H}NMR (126 MHz, CDCl3) 
164.3, 131.8, 131.4, 128.7, 128.6, 68.2, 33.4, 28.0, 26.3; IR (film) max 2912, 1725, 1590, 1398,
79
1263, 1096, 1011, 963, 753 cm-1; HRMS (ESI) calcd. for C7H4O2 Br [M-C4H7S2]- 198.9395;
81
found 198.9391, calcd. for C7H4O2 Br [M-C4H7S2]- 200.9374; found 200.9372.
1,4-dithian-2-yl octanoate (20). Yellow oil (60 mg, 23%); 1H NMR (500 MHz, CDCl3)  5.82
(dd, J = 5.2, 1.9 Hz, 1H), 3.33

3.27 (m, 2H), 3.10

2.97 (m, 1H), 2.88 (dd, J = 14.1, 5.2 Hz, 1H),
1.25 (m, 8H),
2.76 2.69 (m, 2H), 2.39 (t, J = 7.6 Hz, 2H), 1.65 (tt, J = 14.7, 14.7 Hz, 2H), 1.31


0.87 (t, J = 5.2 Hz, 3H); 13C{1H}NMR (126 MHz, CDCl3)  172.4, 67.4, 34.4, 33.3, 31.6, 29.0,
28.9, 28.0, 26.3, 24.9, 22.6, 14.0; IR (film) max 2955, 2927, 2857, 1740, 1466, 1153, 966, 725 cm-
1; HRMS (ESI) calcd. for C12H22O2S2Na [M+Na]+ 285.0959; found 285.0954.
1,4-dithian-2-yl thiophene-2-carboxylate (21). Yellowish amorphous solid (101 mg, 41%);
1H NMR (500 MHz, CDCl3)  7.90 (dd, J = 3.8, 1.3 Hz, 1H), 7.60 (dd, J = 5.0, 1.3 Hz, 1H), 7.12
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(dd, J = 5.0, 3.8 Hz, 1H), 6.03

6.01 (m, 1H), 3.42
3.37 (m, 2H), 3.08 (dd, J = 11.8, 11.8 Hz, 1H),
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2.71 (m, 2H). 13C{1H}NMR (126 MHz, CDCl3)  160.6,
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134.1, 133.2, 133.1, 127.8, 68.2, 33.4, 28.0, 26.3; IR (film) max 3099, 2911, 1709, 1523, 1416,
1253, 1072, 961, 744 cm-1; HRMS (ESI) calcd. for C9H10O2S3Na [M+Na]+ 268.9741; found
268.9734.
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1,4-dithian-2-yl 1-naphthoate (22). Yellowish amorphous solid (154 mg, 53%); 1H NMR (500
MHz, CDCl3)  9.05 (d, J = 8.7 Hz, 1H), 8.40 (dd, J = 7.3, 1.3 Hz, 1H), 8.05 (d, J = 8.2 Hz, 1H),
7.90
3.50


7.88 (m, 1H), 7.64 (ddd, J = 8.6, 5.6, 1.4 Hz, 1H), 7.56
7.52 (m, 2H), 6.206.19 (m, 1H),
3.43 (m, 2H), 3.163.09 (m, 2H), 2.83
2.75 (m, 2H); 13C{1H}NMR (126 MHz, CDCl3) 
165.7, 133.9, 133.8, 131.4, 131.1, 128.6, 128.0, 126.3, 126.3, 125.8, 124.5, 68.1, 33.6, 28.1, 26.3;
IR (film) max 3051, 2911, 1716, 1510, 1237, 1191, 1126, 995, 780 cm-1; HRMS (ESI) calcd. for
C15H14O2S2Na [M+Na]+ 313.0333; found 313.0347.
1,4-dithian-2-yl cinnamate (23). Yellow amorphous solid (69 mg, 26%); 1H NMR (500 MHz,
CDCl3)  7.78 (d, J = 16.0 Hz, 1H), 7.567.54 (m, 2H), 7.407.38 (m, 3H), 6.53 (d, J = 16.0 Hz,
1H), 5.97 (dd, J = 5.2, 2.0 Hz, 1H), 3.403.35 (m, 2H), 3.07 (dd, J = 11.5, 11.5 Hz, 1H), 2.98 (dd,
J = 14.2, 5.2 Hz, 1H), 2.80

2.72 (m, 2H); 13C{1H}NMR (126 MHz, CDCl3)  165.4, 146.0, 134.2,
130.5, 128.9, 128.2, 117.4, 67.7, 33.4, 28.0, 26.3; IR (film) max 3060, 2911, 1713, 1636, 1336,
1151, 977, 768 cm-1; HRMS (ESI) calcd. for C13H14O2S2Na [M+Na]+ 289.0333; found 289.0342.
1-Methoxybutyl benzoate and Butoxymethyl benzoate (35a and 35b) (as a mixture of
1
regioisomers). Colorless oil (120 mg, 23%); H NMR (500 MHz, CDCl3)  8.12

8.03 (m, 4H),
7.597.54 (m, 2H), 7.487.42 (m, 4H), 6.02 (t, J = 5.4 Hz, 1H), 5.54 (s, 2H), 3.72 (t, J = 6.6 Hz,
2H), 3.47 (s, 3H), 1.83
1.79 (m, 2H), 1.641.58 (m, 2H), 1.511.44 (m, 2H), 1.421.35 (m, 2H),
0.96 (t, J = 7.4 Hz, 3H), 0.91 (t, J = 7.4 Hz, 3H); 13C{1H}NMR (126 MHz, CDCl3)  166.3, 166.0,
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133.1, 133.1, 130.1, 129.95, 129.7, 129.5, 128.4, 128.4, 100.4, 90.0, 70.4, 56.7, 36.5, 31.5, 19.1,
17.3, 13.8, 13.7; HRMS (ESI) calcd. for C12H16O3Na [M+Na]+ 231.0997; found 231.0994 for 35a,
calcd. for C12H16O3Na [M+Na]+ 231.0997; found 231.0993 for 35b.
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1,2-dimethoxyethyl benzoate (36). Colorless oil (158 mg, 30%); 1H NMR (500 MHz, CDCl3)
 8.07 (dd, J = 8.4, 1.3 Hz, 2H), 7.56 (tt, J = 7.4, 7.4 Hz, 1H), 7.43 (dd, J = 8.0, 7.6 Hz, 2H), 6.12
(dd, J = 5.2, 4.6 Hz, 1H), 3.62 (dd, J = 10.7, 5.3 Hz, 1H), 3.59 (dd, J = 10.7, 4.6 Hz, 1H), 3.52 (s,
3H), 3.41 (s, 3H); 13C{1H}NMR (126 MHz, CDCl3)  166.0, 133.3, 129.8, 129.5, 128.3, 97.4,
72.7, 59.5, 57.1; IR (film) max 2940, 1724, 1452, 1273, 1093, 926, 713 cm-1; HRMS (ESI) calcd.
for C11H14O4Na [M+Na]+ 233.0790; found 233.0783.
1
1,3-dioxolan-4-yl benzoate (38). Colorless oil (73 mg, 15%); H NMR (500 MHz, CDCl3) 
8.04 (d, J = 8.4 Hz, 2H), 7.597.56 (m, 1H), 7.43 (dd, J = 8.0, 8.0 Hz, 2H), 6.58 (dd, J = 4.1, 1.9
Hz, 1H), 5.19 (br s, 1H), 5.15 (br s, 1H), 4.17 (dd, J = 9.5, 4.2 Hz, 1H), 4.12 (dd, J = 9.5, 1.9 Hz,
1H); 13C{1H}NMR (126 MHz, CDCl3)  165.8, 133.5, 129.8, 129.4, 128.4, 95.9, 94.6, 70.7; IR
(film) max 2881, 1728, 1452, 1271, 1092, 922, 712 cm-1; HRMS (ESI) calcd. for C10H10O4Na
[M+Na]+ 217.0477; found 217.0470.
2-methyl-1,3-dioxolan-2-yl benzoate (39a). Colorless oil (270 mg, 52%); 1H NMR (400 MHz,
CDCl3)  8.00 (dd, J = 8.4, 1.4 Hz, 2H), 7.52 (tt, J = 6.8, 1.3 Hz, 1H), 7.39 (dd, J = 7.8, 7.8 Hz,
2H), 4.484.46 (m, 2H), 4.38
4.35 (m, 2H), 2.04 (s, 3H); 13C{1H}NMR (120 MHz, CDCl3) 
170.6, 166.1, 133.0, 129.6, 129.5, 128.2, 62.5, 62.0, 20.6; IR (film) max 2960, 1743, 1722, 1452,
1375, 1278, 1232, 1062, 712 cm-1; HRMS (ESI) calcd. for C11H12O4Na [M+Na]+ 231.0633; found
231.0628.
trans-2-methyl-1,3-dioxolan-4-yl benzoate (39b). Colorless oil (52 mg, 10%); 1H NMR (400
MHz, CDCl3)  8.04 (dd, J = 8.4, 1.3 Hz, 2H), 7.58 (tt, J = 6.9,1.3 Hz, 1H), 7.44 (dd, J = 8.0, 8.0
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Hz, 2H), 6.57 (dd, J = 4.8, 2.7 Hz, 1H), 5.37 (q, J = 4.8 Hz, 1H), 4.37 (dd, J = 9.5, 4.8 Hz, 1H),
4.01 (dd, J = 9.5, 2.7 Hz, 1H), 1.45 (d, J = 4.9 Hz, 3H); 13C{1H}NMR (100 MHz, CDCl3)  165.8,
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133.5, 129.8, 129.5, 128.4, 102.4, 95.5, 71.0, 19.2; IR (film) max 2994, 2894, 1729, 1452, 1272,
1158, 1057, 981, 712 cm-1; HRMS (ESI) calcd. for C11H12O4Na [M+Na]+ 231.0633; found
231.0626.
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cis-2-methyl-1,3-dioxolan-4-yl benzoate (39c). Colorless oil (21 mg, 4%); H NMR (400
MHz, CDCl3)  8.05 (dd, J = 8.4, 1.3 Hz, 2H), 7.58 (tt, J = 6.9,1.3 Hz, 1H), 7.45 (dd, J = 7.9, 7.9
Hz, 2H), 6.52 (d, J = 3.6 Hz, 1H), 5.31 (q, J = 4.9 Hz, 1H), 4.32 (d, J = 9.8 Hz, 1H), 4.02 (dd, J =
9.8, 3.7 Hz, 1H), 1.51 (d, J = 4.9 Hz, 3H);13C{1H}NMR (100 MHz, CDCl3)  165.9, 133.4, 129.8,
129.7, 128.4, 104.6, 94.9, 71.6, 21.2; IR (film) max 2999, 2884, 1726, 1272, 1157, 1067, 1024,
981, 712 cm-1; HRMS (ESI) calcd. for C11H12O4Na [M+Na]+ 231.0633; found 231.0634.
Tetrahydrothiophen-2-yl benzoate (40). Yellowish amorphous solid (96 mg, 46%); 1H NMR
(500 MHz, CDCl3)  8.01 (dd, J = 8.3, 1.2 Hz, 2H), 7.56
(dd, J = 4.8, 1.4 Hz, 1H), 3.07 (ddd, J = 9.8, 7.1, 2.3 Hz, 1H), 2.86 (ddd, J = 10.4, 10.4, 6.2 Hz,
1H), 2.46 2.42 (m, 1H), 2.31 2.24 (m, 1H), 2.21 2.11 (m, 1H), 2.06 1.98 (m, 1H);
7.52 (m, 1H), 7.437.40 (m, 2H), 6.42




13C{1H}NMR (126 MHz, CDCl3)  166.0, 133.0, 130.1, 129.6, 128.3, 83.6, 37.4, 32.4, 28.4; IR
(film) max 2961, 2936, 1717, 1451, 1269, 1096, 1025, 921, 710 cm-1; HRMS (ESI) calcd. for
C11H12O2SNa [M+Na]+ 231.0456; found 231.0453.
1,4-oxathian-3-yl benzoate (41a). White amorphous solid (308 mg, 55%); 1H NMR (500 MHz,
CDCl3)  8.12 (dd, J = 8.4, 1.3 Hz, 2H), 7.57 (tt, J = 7.4, 1.3 Hz, 1H), 7.45 (dd, J = 7.8, 7.8 Hz,
2H), 5.79 (br s, 1H), 4.27 (br s, 1H), 4.24 (br s, 1H), 4.02 (dd, J = 12.6, 1.7 Hz, 1H), 3.86 (ddd, J
= 11.8, 11.8, 2.0 Hz, 1H), 3.39

3.34 (m, 1H), 2.30 (br d, J = 13.6 Hz, 1H); 13C{1H}NMR (126
MHz, CDCl3)  165.35, 133.3, 129.9, 129.8, 128.4, 71.2, 68.7, 68.0, 23.5; IR (film) max 3063,
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2952, 2854, 1719, 1451, 1262, 1097, 1008, 711 cm-1; HRMS (ESI) calcd. for C11H12O3SNa
[M+Na]+ 247.0405; found 247.0404.
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1,4-oxathian-2-yl benzoate (41b). White amorphous solid (84 mg, 15%); 1H NMR (500 MHz,
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CDCl3)  8.10 (dd, J = 8.4, 1.3 Hz, 2H), 7.587.56 (m, 1H), 7.45 (dd, J = 7.7., 7.7 Hz, 2H), 6.17
(br s, 1H), 4.35 (br s, 1H), 4.01 (br s, 1H), 2.83 (br s, 2H), 2.64 (br s, 2H); 13C{1H}NMR (126
MHz, CDCl3)  164.7, 133.4, 129.86, 129.5, 128.4, 91.2, 66.0, 29.5, 25.8; IR (film) max 3063,
2920, 1728, 1452, 1269, 1062, 955 cm-1; HRMS (ESI) calcd. for C11H12O3SNa [M+Na]+ 247.0405;
found 247.0402.
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AUTHOR INFORMATION
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Corresponding author
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*E-mail: francisco.guerra@uca.es
Notes
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The authors declare no competing financial interest.
ACKNOWLEDGMENTS
We are grateful to the Ministry of Economy and Competitiveness of Spain (Projects AGL2013-
42238-R, CSD2009-00013, and MINECO/FEDER MAT2013-40823-R) and the Junta de
Andalucía (FQM-169 and FQM-110 groups) for the financial support. A. L. G.-C. and R. M.-B.
acknowledge the Spanish Ministry of Education, Culture and Sport for a fellowship. We also thank
the SC-ICYT of the University of Cádiz for the use of its XRD, AS, NMR and electron microscopy
division facilities.
ASSOCIATED CONTENT
Supporting information
Physical characterization of the catalyst and NMR spectra for all compounds. This material is
available free of charge via the Internet at http://pubs.acs.org.
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