Synthesis of Oxazolidinones from Epoxides and Isocyanates Catalyzed by Rare-Earth-Metal Complexes

Article abstract of DOI:10.1002/cctc.201403015

Rare-earth-metal complexes stabilized by an amino-bridged triphenolate ligand showed high efficiency in catalyzing the cycloaddition of isocyanates and epoxides in the presence of NBu₄I under mild conditions. This strategy is applicable to both

Full text of DOI:10.1002/cctc.201403015

DOI: 10.1002/cctc.201403015
Full Papers
Synthesis of Oxazolidinones from Epoxides and
Isocyanates Catalyzed by Rare-Earth-Metal Complexes
Peng Wang, Jie Qin, Dan Yuan,* Yaorong Wang, and Yingming Yao*[a]
Rare-earth-metal complexes stabilized by an amino-bridged tri-
phenolate ligand showed high efficiency in catalyzing the cy-
cloaddition of isocyanates and epoxides in the presence of
NBu4I under mild conditions. This strategy is applicable to
both terminal and disubstituted epoxides as well as various
isocyanates, and tolerated different types of functional groups.
Moreover, it is highly regio- and stereoselective, and afforded
3,5-disubstituted oxazolidinones as the only products in most
cases in moderate to good yields.
Introduction
Oxazolidinones are important intermediates in organic synthe-
sis. For instance, they are commonly used to prepare b-amino-
alcohols,[1] and are valuable building blocks for polymers.[2] In
addition, they also serve as precursors to antibacterial medi-
cines such as Staphylococcus aureus, Enterococcus faecium,
Streptococcus pneumoniae.[3,4] Hence, the construction of oxa-
zolidinone frameworks is of significant importance.
decent yields. Slow addition of isocyanates or large excess of
epoxides was required to suppress the trimerization of isocya-
nates, which is a common side reaction.[22,24,27] Moreover, sub-
strate scopes are largely limited to monosubstituted epox-
ides.[27–29]
Very recently, North et al. reported a bimetallic Al-Salen com-
plex which efficiently catalyzed the coupling of isocyanates
and epoxides.[44] With 5 mol% catalyst, 33–100% conversions
were achieved, and isomers of 3,4-disubstituted and 3,5-disub-
stituted oxazolidinones formed in varying ratios. Nguyen et al.
reported a CrIII–Salen complex that in the presence of a Lewis
base catalyzed the oxazolidinone formation reactions in good
yields of >90% with 3,5-disubstituted 2-oxazolidinones as the
major products.[45]
Many efforts have been made to prepare oxazolidinones,
which include reactions of carbon dioxide with b-aminoalco-
hols or aziridines,[5–11] oxidative carbonylation of b-aminoalco-
hols with CO/O2,[12–16] and carbonylation of b-aminoalcohols
with dialkyl carbonate.[17–19] Among them, the [3+2] addition
of isocyanates to epoxides (Scheme 1) is a 100% atom-eco-
Rare-earth-metal complexes are highly oxophilic, which
makes them potentially useful in activating epoxides. Although
some rare-earth-metal salts have been reported to catalyze the
cycloaddition of isocyanates and epoxides, 10 mol%[31,32] or
substoichiometric amounts[33] of catalyst were required. Our
group has reported a series of rare-earth-metal complexes sta-
bilized by a bridged poly(phenolate) ligand, which catalyzed
the cycloaddition of carbon dioxide with both terminal and
disubstituted epoxides under mild conditions and showed
high activity and regioselectivity.[46] As both carbon dioxide
and isocyanates are heterocumulenes,[27,30,37,47,48] we were
prompted to explore the performance of rare-earth-metal com-
plexes in catalyzing the reaction between isocyanates and ep-
oxides.
Scheme 1. Formation of oxazolidinones from epoxides and isocyanates.
nomic strategy, and has thus attracted substantial attention.
Many catalytic systems have been reported to catalyze this
transformation, including onium salts,[20] metal halides,[21–41]
and Pd0 species.[42,43] However, harsh conditions, such as high
catalyst loadings (usually more than 10%),[26,29–31,33,37] and high
temperature exceeding 1608C[20] were usually required to get
Results and Discussion
[a] P. Wang, J. Qin, Dr. D. Yuan, Prof. Y. Wang, Prof. Y. Yao
Key Laboratory of Organic Synthesis of Jiangsu Province
College of Chemistry, Chemical Engineering and Materials Science
Dushu Lake Campus, Soochow University
Suzhou 215123 (P.R. China)
Amino-bridged triphenolate ligands (LH3) have been reported
to be useful in stabilizing trivalent rare-earth metals, and their
complexes have been applied in catalyzing various transforma-
tions, including the coupling of epoxides and carbon diox-
ide,[49,50] lactide polymerization,[51–54] and ethylene/propylene
copolymerization.[55] The ligand precursor LH3 was readily pre-
pared according to a literature method.[56] Treating LnCp3(THF)
Fax: (+86)512-65880305
E-mail: yuandan@suda.edu.cn
yaoym@suda.edu.cn
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/cctc.201403015.
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Table 1. Reactions of propylene oxide with phenylisocyanate.[a]
[b]
Entry
Cat.
Cocat.
Solvent
T
[8C]
Conc.
[mmolmLÀ1
]
Yield
[%]
1
2
3
4
7
7
–
7
7
7
7
7
–
toluene
toluene
toluene
toluene
toluene
toluene
toluene
bromo-
benzene
xylene
80
80
80
60
18
80
80
80
2.14
2.14
2.14
2.14
2.14
2.14
2.14
2.14
0
47
23
33
0
37
52
44
NBu4Br
NBu4Br
NBu4Br
NBu4Br
NBu4Br
NBu4Br
NBu4Br
Scheme 2. Synthesis of complexes 5–8.
5
6[c]
7[d]
8
(Ln=Y, Sm, Nd, La) with LH3 in THF afforded four complexes
isolated in 64–87% yields after 12 h reaction at room tempera-
1
ture (Scheme 2). H NMR spectra of diamagnetic complexes 5
9
10
7
7
NBu4Br
NBu4Br
80
80
2.14
2.14
43
7
and 8 in [D8]THF showed that all three phenolate moieties of
the ligand gave rise to one set of signals, with the diastereo-
topic methylene protons resonating as two doublets at 3.98
and 2.62 ppm, respectively. Resonances assignable to THF mol-
ecules are also observed, suggesting the existence of coordi-
nating THF molecules. The unambiguous identity of these
complexes was confirmed by the solid-state structures of com-
plexes 6–8 determined by X-ray diffraction on single crystals
obtained from hexane/THF solution. All three complexes are
isostructural with the structure of 7 depicted in Figure 1. Each
cyclic
carbonate
solvent
free
11
7
NBu4Br
80
–
18
12
13
14
15
16
17
18
19
20[f]
21[g]
22[h]
7
7
7
5
6
8
7
7
7
7
7
NBu4Br
NBu4Br
NBu4Br
NBu4Br
NBu4Br
NBu4Br
NBu4I
PPNCl[e]
NBu4I
NBu4I
NBu4I
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
toluene
80
80
80
80
80
80
80
80
80
80
80
1.07
0.71
0.54
0.71
0.71
0.71
0.71
0.71
0.71
0.71
0.71
63
81
86
72
69
80
87
37
91
93
98
[a] Reaction conditions, unless otherwise stated: propylene oxide (0.3 mL,
4.28 mmol), phenylisocyanate (0.47 mL, 4.28 mmol), 0.3 mol% catalyst,
0.3 mol% cocatalyst, 18 h; [b] Determined by 1H NMR spectroscopy;
[c] 12 h reaction time; [d] 24 h reaction time; [e] bis(triphenylphosphine)-
iminium chloride; [f] 0.3 mol% catalyst, 0.67 mol% cocatalyst;
[g] 0.3 mol% catalyst, 1 mol% cocatalyst; [h] 0.5 mol% catalyst, 1 mol%
cocatalyst.
ammonium halide plays a crucial role in initiating the reaction
of epoxides with rare-earth metals. A control experiment re-
vealed that NBu4Br alone was also active and gave rise to
a 23% yield (entry 3), which is approximately half of the result
obtained from the combination of complex 7 and NBu4Br
(entry 2). Ring-opening of epoxides by the halides and subse-
quent addition reaction with isocyanate has also been ob-
served by Speranza and Peppel.[20] In the presence of rare-
earth-metal complexes, coordination to metal centers activates
epoxides towards ring-opening, which were readily attacked
by the nucleophilic reagent XÀ to produce the requisite metal
alkoxide intermediate. On the other hand, no oxazolidinone
formed in the absence of halide, because the ring-opening of
epoxides did not proceed. In contrast, no cocatalyst was re-
quired for the bimetallic aluminum–salen catalytic system,
which may be attributed to the existence of a Lewis basic
oxygen atom that bridges the two Al centers.[44] 3,5-Disubsti-
tuted oxazolidinone 3a was isolated as the only product, sug-
gesting that the b-cleavage of epoxides at the less hindered
carbon atom predominates. Different reaction conditions were
then screened in the presence of both 7 and NBu4Br. Lowering
the reaction temperature to 608C led to a lower yield of 33%
(entry 4), and no conversion was detected at 188C (entry 5).
18 h proved to be the optimal reaction time as shortening it
Figure 1. Molecular structure of complex 7·3THF showing 50% probability
ellipsoids. Solvent molecules and hydrogen atoms are omitted for clarity.
rare-earth-metal center is coordinated by four donors (O1, O2,
O3, and N1) from the phenolate ligand, and three oxygen
atoms from three THF molecules. The coordination geometry
can be best described as orthorhombic.
With all four complexes in hand, we examined their per-
formance in catalyzing reactions between phenylisocyanate
and propylene oxide. No conversion was detected at all if the
reaction was conducted in the presence of 0.3 mol% of the
neodymium complex 7 at 808C after 18 h reaction in toluene
(Table 1, entry 1). However, the addition of 0.3 mol% NBu4Br
led to a dramatically improved yield of 47% (entry 2). A similar
finding was observed in the reaction of carbon dioxide and ep-
oxides catalyzed by rare-earth-metal complexes.[46] Apparently,
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to 12 h led to a reduced yield of 37% (entry 6), whereas pro-
longing it to 24 h resulted in a 5% increase only (entry 7). Re-
actions conducted in xylene and bromobenzene afforded the
desired product 3a in similar yields (entries 8–9), whereas a sig-
nificantly lower yield of 7% was obtained from that in cyclic
carbonate (entry 10). Notably, 18% of 3a was isolated if the re-
action was conducted neat, although 72% of PhNCO was
transformed into the byproduct resulting from its trimerization
(entry 11). Apparently, the undesired trimerization can be sup-
pressed in this catalytic system by simply diluting the reaction
mixture, which thus avoids the need to add large excess of ep-
oxides or to add isocyanates portionwise.[22,24,27] To identify the
optimal concentration for oxazolidinone formation, different
amounts of toluene were screened. The results reveal a raise of
the yield from 18% to 86% if the solvent volume increased
from 0 to 8 mL (entries 11–14). Complexes of different metal
centers and different Lewis acidities were also tested under
identical conditions. 5 and 6 bearing rare-earth metals of small
ionic radii led to lower yields of 72 and 69%, respectively,
whereas 7 and 8 showed better activities and gave rise to
yields of 81% and 80%, respectively (entries 15–17). This may
be explained by the larger open coordination sphere of the
larger rare-earth metals which may be helpful for activation of
propylene oxide. Different cocatalysts including NBu4I and bis-
(triphenylphosphine)iminium chloride (PPNCl) were also tested,
and NBu4I proved to be the optimal choice (entries 18–19).
Studies on different loadings of catalyst and cocatalyst re-
vealed that 0.5 mol% of 7 and 1 mol% of NBu4I were the best
combination, and led to an almost quantitative yield (en-
tries 20–22).
Table 2. Formation of oxazolidinones from epoxides and phenylisocya-
nate catalyzed by complex 7.[a]
Entry
1
Epoxide
Product
Yield [%][b] 3:4[c]
72
1:0
2
89[d] (26[e]
)
2.1:1
3
4
5
6
86
1:0
9:1
1:0
1:0
82[f]
93[d] (15[e]
)
93[f]
7
8
73
0:1
1:0
83[f]
With the optimal reaction conditions, the scope of sub-
strates was explored. Epoxides bearing a phenyl (1b), chloro-
methyl (1c), or n-butyl (1d) group were converted to the cor-
responding oxazolidinones in 82–89% yields (Table 2, en-
tries 2–4). Reaction with epoxides carrying ether groups (1e
and 1 f) also proceeded straightforwardly without deactivating
the catalyst, and afforded the desired products in the same
yield of 93% (entries 5–6). In comparison, control experiments
in the absence of complex 7 resulted in oxazolidinones in less
than 30% yields (entries 2 and 5), which further confirms that
rare-earth-metal complexes play a crucial role in catalyzing this
transformation.
9
72
28
1:0
10
–
11
12
69[f,g]
–
Notably, glycidol 1g bearing an unprotected hydroxyl
group, which might poison the rare-earth-metal complex, was
also converted to the desired product 4g in a good yield of
73% (entry 7). Other functional groups, including an alkene
(1h) and an ester group (1i), were also tolerated under the es-
tablished conditions, and corresponding oxazolidinones were
isolated in 83% and 72%, respectively (entries 8–9).
95[f]
1:0
[a] Reactions conditions, unless otherwise stated: oxides (conc. =
0.71 mmolmLÀ1), 0.5 mol% catalyst, 1.0 mol% NBu4I, 18 h, 808C; [b] Iso-
lated yield; [c] Determined by 1H NMR spectroscopy; [d] The same
amount of NBu4Br was used instead of NBu4I; [e] In the absence of 7;
[f] 1.0 mol% catalyst and 2.0 mol% NBu4I were used; [g] The cis-fused
structure was determined by X-ray diffraction analysis on single crystals.
3,5-Disubstituted oxazolidinones formed almost exclusively
in most cases, revealing excellent regioselectivity of this strat-
egy. The reaction with styrene oxide yielded both 3,5-diphenyl-
oxazolidinone 3b and 3,4-diphenyloxazolidinone 4b in the
ratio of 2.1:1, the latter of which resulted from the favorable
ring-opening at the benzylic position.[44] A mixture of 3,5-di-
substituted and 3,4-disubstituted oxazolidinones in 9:1 ratio
was also observed from the reaction with 1,2-epoxyhexane 1d.
3,4-Disubstituted oxazolidinone from glycidol 1g was obtained
as the only product, which is consistent with previous reports
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that isocyanates first react with the hydroxyl group followed
by intramolecular reaction with epoxide.[44,57–61]
which generated oxazolidinones in 85–89% yields (entries 1–
2). Although the catalyst loadings were increased, electron-de-
ficient arylisocyanates led to lower yields of 57–82% (en-
tries 3–6). Moreover, 5-substituted 2-oxazolidinone isomers
formed exclusively in all cases. Rare-earth-metal complexes
proved limited in catalyzing the reaction with aliphatic isocya-
nates, as almost no conversion was detected for cyclohexyliso-
cyanate (entries 7–8).
Nonterminal epoxides have been reported to be challenging
substrates for this transformation.[27,28,29,44] In our system, cis-cy-
clohexene oxide (1j) and cis-cyclopentene oxide (1k) were
transformed to corresponding oxazolidinones in 28 and 69%
yields, respectively. 1H NMR spectra show the existence of
single diastereomers, and the solid state structure of 3k was
determined by X-ray diffraction analysis on single crystals,
which proves that the two rings are cis-fused to each other
(Supporting Information, Figure S3). It is thus conceivable that
the formation of 3k underwent a double inversion process,[44]
which results in the retention of the epoxide stereochemistry.
This finding is consistent with the result from the coupling of
cyclohexene oxide and cyclopentene oxide with CO2 catalyzed
by rare-earth-metal complexes and NBu4I.[46] In the presence of
higher loading of catalyst and cocatalyst, 1,2-dimethylepoxide
(1l) reacted with PhNCO and yielded 3l in 95%.
Conclusions
Rare-earth-metal complexes stabilized by an amino-bridged tri-
phenolate ligand were prepared, which showed high activity
towards the cycloaddition of isocyanates and epoxides. Various
terminal and disubstituted epoxides and arylisocyanates were
studied, and oxazolidinones were isolated in generally moder-
ate to good yields in the presence of 0.5–2.0 mol% catalyst
and 1.0–4.0 mol% NBu4I as a cocatalyst. Good regioselectivity
was achieved and the 3,5-disubstituted isomers formed exclu-
sively in most cases. The cis-configuration of substrates was re-
tained after reaction, revealing an excellent stereoselectivity.
Further investigations on the tuning of the structure of the li-
gands and complexes to search for catalysts of enhanced activ-
ities are ongoing in our laboratory.
Besides epoxides, various arylisocyanates bearing either an
electron-donating or electron-withdrawing para-substituent
were also tested, and the results are summarized in Table 3. In
general, reactions with electron-rich substrates worked better,
Table 3. Formation of oxazolidinones from propylene oxide and isocya-
nates catalyzed by complex 7.[a]
Experimental Section
Entry
1
Isocyanate
Product
Yield [%][b]
3:4[c]
Oxides, isocyanates, and onium salts were commercially available.
Hexane, toluene, and THF were freshly distilled after heating to
reflux over sodium/benzophenone ketyl prior to use. The ligand
precursor LH3 was prepared according to the previous literature.[56]
Standard Schlenk techniques were applied to synthesize rare-
earth-metal complexes 5–8. Elemental analysis was performed with
a CarloErba EA-1110 instrument. The IR spectra were performed
with a Nicolet-550 FT-IR spectrometer. NMR (1H, 13C, 19F) spectra
were recorded on a Unity Varian AC-400 spectrometer. The struc-
89
1:0
2
85
1:0
3
4
67[d]
1:0
1:0
tures of rare-earth-metal complexes
6
(CCDC 1038013),
7
(CCDC 1038014), 8 (CCDC 1038015) were detected by X-ray single-
crystal diffractometry. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
82[d]
5
6
7
68[d]
1:0
1:0
–
Procedure for the synthesis of rare-earth-metal complexes
5–8
Complex 5: A 2 mL volume of THF solution of LH3 (0.8380 g,
2.00 mmol) was added to a 4 mL volume of THF solution of
Y(C5H5)3(THF) (0.7126 g, 2.00 mmol). After stirring for 12 h at RT, the
reaction mixture was concentrated under vacuum. THF (2 mL) was
added to extract the residue, and the solid that remained insoluble
was removed after centrifugation. To the THF solution, hexane
(4 mL) was added. Yellow crystals were obtained after several days
from the THF/hexane solution at RT (0.9228 g, 1.28 mmol, 64%). IR
(KBr pellet): n˜ =3380 (s), 2910 (w), 1606 (s), 1469 (s), 1378 (s), 1340
(s), 1306 (s), 1250 (s), 1151 (s), 1049 (s), 850 (s), 801 (s), 752 (s), 640
(s), 631 (s), 625 cmÀ1 (s); elemental analysis calcd (%) for
C39H54NO6Y: C 63.55, H 6.90, N 1.78, Y 12.46; found: C 63.90, H
57[e]
trace
8
trace
–
[a] Reactions conditions, unless otherwise stated: oxides (conc. =
0.71 mmolmLÀ1), 0.5 mol% catalyst, 1.0 mol% NBu4I, 18 h, 808C; [b] Iso-
lated yield; [c] Determined by 1H NMR spectroscopy; [d] 1.0 mol% cata-
lyst, 2.0 mol% NBu4I; [e] 2.0 mol% catalyst, 4.0 mol% NBu4I, 958C.
1
7.54, N 1.94, Y 12.32; H NMR ([D8]THF, 400 MHz): d=6.70 (s, 3H,
ArH), 6.61 (s, 3H, ArH), 3.98 (d, J=11.32 Hz, 3H, ArCHHN), 3.69–
3.63 (m, THF), 2.65 (d, J=11.32 Hz, 3H, ArCHHN), 2.14 (s, 9H, CH3),
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2.10 (s, 9H, CH3), 1.85–1.80 ppm (m, THF) (owing to the exchange
of coordinating THF with [D8]THF, correct integration is not possi-
ble). 13C NMR ([D8]THF, 100 MHz): 160.5, 129.5, 128.1, 123.5, 123.2,
121.5 (Ar-C), 60.4 (ArCH2N), 19.6, 16.8 (CH3).
200.0687, found: 200.0691; calcd for (2ꢁC10H11NO2)Na+: 377.1478,
found: 377.1484.
3,5-Diphenyloxazolidin-2-one (3b):[27,44,45] White solid. 1H NMR
(CDCl3, 400 MHz): d=7.61–7.35 (m, 9H, ArH), 7.18 (tt, J=7.4,
1.1 Hz, 1H, ArH), 5.67 (dd, J=8.4, 8.2 Hz, 1H, CH), 4.42 (t, J=8.8 Hz,
1H, CH2), 3.99 ppm (dd, J=8.8, 7.6 Hz, 1H, CH2); m/z (ESI-TOF):
calcd for C15H13NO2Na+: 262.0844, found: 262.0842; calcd for (2ꢁ
C15H13NO2)Na+: 501.1790, found: 501.1805.
Complex 6 was synthesized in analogy to complex 5 from
Sm(C5H5)3(THF) (0.8340 g, 2.00 mmol). After removal of solvent in
vacuum, THF (2 mL) was added to extract the residue, and the
solid that remained insoluble was removed after centrifugation.
Yellow crystals were obtained after several days from the THF solu-
tion at RT (1.2518 g, 1.60 mmol, 80%). IR (KBr pellet): n˜ =3390 (s),
2916 (w), 1610 (s), 1478 (s), 1386 (s), 1365 (s), 1307 (s), 1263 (s),
1160 (s), 1054 (s), 855 (s), 810 (s), 760 (s), 660 (s), 630 cmÀ1 (s); ele-
mental analysis calcd (%) for C39H54NO6Sm: C 59.81, H 6.95, N 1.79,
Sm 19.20; found: C 59.46, H 6.89, N 1.88, Sm 18.85.
3,4-Diphenyloxazolidin-2-one (4b):[27,44,45] White solid. 1H NMR
(CDCl3, 400 MHz): d=7.45–7.20 (m, 9H, ArH), 7.06 (tt, J=7.4,
1.1 Hz, 1H, ArH), 5.39 (dd, J=8.7, 6.0 Hz, 1H, CH), 4.78 (t, J=8.7 Hz,
1H, CH2), 4.20 ppm (dd, J=8.6, 6.0 Hz, 1H, CH2); m/z (ESI-TOF):
calcd for C15H13NO2Na+: 262.0844, found: 262.0844; calcd for (2ꢁ
C15H13NO2)Na+: 501.1790, found: 501.1800.
Complex 7 was synthesized in analogy to complex 5 from
Nd(C5H5)3(THF) (0.8228 g, 2.00 mmol). After removal of solvent in
vacuum, THF (2 mL) was added to extract the residue, and the
solid that remained insoluble was removed after centrifugation.
Blue crystals were obtained after several days from the THF solu-
tion at RT (1.3196 g, 1.70 mmol, 85%). IR (KBr pellet): n˜ =3411 (s),
2918 (w), 1613 (s), 1478 (s), 1383 (s), 1346 (s), 1310 (s), 1258 (s),
1160 (s), 1056 (s), 858 (s), 800 (s), 759 (s), 641 (s), 624 cmÀ1 (s); ele-
mental analysis calcd (%) for C39H54NO6Nd: C 58.88, H 6.84, N 1.84,
Nd 18.90; found: C 60.28, H 7.00, N 1.80, Nd 18.56.
5-Chloromethyl-3-phenyloxazolidin-2-one (3c):[27,44,45] White solid.
1H NMR (CDCl3, 400 MHz): d=7.56 (d, J=7.9 Hz, 2H, ArH), 7.42 (t,
J=7.5 Hz, 2H, ArH), 7.19 (t, J=7.3 Hz, 1H, ArH), 4.95–4.85 (m, 1H,
CH), 4.20 (t, J=8.9 Hz, 1H, CH2), 4.00 (dd, J=8.9, 5.8 Hz, 1H, CH2),
3.87–3.7 ppm (m, 2H, CH2Cl); m/z (ESI-TOF): calcd for
C10H10ClNO2Na+: 234.0298, found: 234.0298; calcd for (2ꢁ
C10H10ClNO2)Na+: 445.0698, found: 445.0709.
5-Butyl-3-phenyloxazolidin-2-one (3d):[44,45] White solid. 1H NMR
(CDCl3, 400 MHz): d=7.56 (d, J=7.8 Hz, 2H, ArH), 7.40 (t, J=7.5 Hz,
2H, ArH), 7.15 (tt, J=7.3, 2.0 Hz, 1H, ArH), 4.70–4.61 (m, 1H, CH),
4.10 (t, J=8.5 Hz, 1H, CH2), 3.68 (dd, J=8.6, 7.2 Hz, 1H, CH2), 1.94–
1.83 (m, 1H, CH2), 1.81–1.71 (m, 1H, CH2), 1.59–1.50 (m, 1H, CH2),
1.48–1.38 (m, 3H, CH2), 0.97 ppm (t, J=7.0 Hz, 3H, CH3); m/z (ESI-
TOF): calcd for C13H17NO2Na+: 242.1157, found: 242.1158; calcd for
(2ꢁC13H17NO2)Na+: 461.2416, found: 461.2428.
Complex 8 was synthesized in analogy to complex 5 from
La(C5H5)3(THF) (0.8126 g, 2.00 mmol). After removal of solvent in
vacuum, THF (2 mL) was added to extract the residue, and the
solid remained insoluble was removed after centrifugation. Color-
less crystals were obtained after several days from the THF solution
at RT (1.3414 g, 1.74 mmol, 87%). IR (KBr pellet): n˜ =3425 (s), 2914
(w), 1610 (s), 1478 (s), 1384 (s), 1306 (s), 1257 (s), 1160 (s), 1053 (s),
857 (s), 802 (s), 762 (s), 613 (s), 603 cmÀ1 (s); elemental analysis
calcd (%) for C39H54NO6La: C 60.93, H 6.69, N 1.82, La 18.07; found:
4-Butyl-3-phenyloxazolidin-2-one (4d):[44,45] White solid. 1H NMR
(CDCl3, 400 MHz): d=7.48–7.37 (m, 4H, ArH), 7.21 (tt, J=7.2,
1.8 Hz, 1H, ArH), 4.56 (t, J=8.4 Hz, 1H, CH), 4.48–4.39 (m, 1H, CH2),
4.16 (dd, J=8.4, 5.4 Hz, 1H, CH2), 1.83–1.72 (m, 1H, CH2), 1.65–1.53
(m, 1H, CH2), 1.40–1.20 (m, 4H, CH2), 0.89 ppm (t, J=6.9 Hz, 3H,
CH3); m/z (ESI-TOF): calcd for C13H17NO2H+: 220.1138, found:
220.1125; calcd for C13H17NO2Na+: 242.1157, found: 242.1149; calcd
for (2ꢁC13H17NO2)Na+: 461.2416, found: 461.2426.
1
C 60.58, H 6.84, N 1.84, La 18.82; H NMR ([D8]THF, 400 MHz): d=
6.70 (s, 3H, ArH), 6.61 (s, 3H, ArH), 3.96 (d, J=11.32 Hz, 3H,
ArCHHN); 3.68–3.62 (m, THF), 2.63 (d, J=11.32 Hz, 3H, ArCHHN),
2.14 (s, 9H, CH3), 2.12 (s, 9H, CH3), 1.85–1.80 ppm (m, THF) (owing
to the exchange of coordinating THF with [D8]THF, correct integra-
tion is not possible); 13C NMR ([D8]THF, 100 MHz): d=161.4, 130.2,
128.8, 123.5, 121.2(Ar-C), 60.4(ArCH2N), 19.5, 16.6 ppm (CH3).
5-Phenoxymethyl-3-phenyloxazolidin-2-one (3e):[27,37,44,45] White
solid. 1H NMR (CDCl3, 400 MHz): d=7.58 (d, J=8.6 Hz, 2H, ArH),
7.40 (t, J=8.6 Hz, 2H, ArH), 7.30 (t, J=7.4 Hz, 2H, ArH), 7.16 (tt, J=
7.3, 1.8 Hz, 1H, ArH), 7.00 (tt, J=7.4, 1.8 Hz, 1H, ArH), 6.91 (d, J=
7.8 Hz, 2H, ArH), 5.03–4.95 (m, 1H, CH), 4.25–4.18 (m, 3H, CH2),
4.08 ppm (dd, J=8.9, 5.9 Hz, 1H, CH2); m/z (ESI-TOF): calcd for
C16H15NO3Na+: 292.0950, found: 292.0951; calcd for (2ꢁ
C16H15NO3)Na+: 561.2002, found: 561.2018.
General procedure for the synthesis of oxazolidinones
Complex
7 (0.0167 g, 0.0215 mmol) and cocatalyst (0.0138 g,
0.0429 mmol) were added to a 10 mL flask equipped with a mag-
netic stirring bar under dry argon atmosphere, to which toluene
(6–8 mL) was added. Epoxide (4.2872 mmol) and isocyanate
(4.2872 mmol) were added to the above stirred solution before
heating the solution to 808C for 18–24 h. After the reaction, the re-
sulting mixture was cooled to RT. The conversion and selectivity
5-Methoxymethyl-3-phenyloxazolidin-2-one (3 f): White solid.
1H NMR (CDCl3, 400 MHz): d=7.57 (d, J=8.7 Hz, 2H, ArH), 7.39 (t,
J=7.4 Hz, 2H, ArH), 7.15 (m, 1H, ArH), 4.83–4.74 (m, 1H, CH), 4.07
(t, J=8.8 Hz, 1H, CH2), 3.93 (dd, J=8.7, 6.4 Hz, 1H, CH2), 3.66 (d,
J=4.6 Hz, 2H, OCH2), 3.45 ppm (s, 3H, CH3); 13C NMR (CDCl3,
100 MHz): d=154.5, 138.1, 129.0, 123.9, 118.0, 73.1, 71.3, 59.5,
47.2 ppm. IR (KBr): n˜ =3101, 3074, 3048, 3019, 2994, 2948, 2929,
2865, 2830, 1738, 1702, 1596, 1493, 1414, 1226, 1129, 1066, 1047,
755, 689, 585, 505 cmÀ1. m/z (ESI-TOF): calcd for C11H13NO3Na+:
230.0793, found: 230.0799; calcd for (2ꢁC11H13NO3)Na+: 437.1688,
found: 437.1700.
1
were analyzed by H NMR spectroscopy on one drop of the mix-
ture. The solvent of the mixture was removed in vacuum. The de-
sired compound was purified by column chromatography (eluent:
ethyl acetate: petroleum ether=1: 20).
5-Methyl-3-phenyloxazolidin-2-one (3a):[27,30,37,44,45] White solid.
1H NMR (CDCl3, 400 MHz): d=7.56 (d, J=8.0 Hz, 2H, ArH), 7.40 (t,
J=7.6 Hz, 2H, ArH), 7.15 (t, J=7.4 Hz, 1H, ArH), 4.85–4.75 (m, 1H,
CH), 4.14 (t, J=8.4 Hz, 1H, CH2), 3.65 (dd, J=8.3, 7.4 Hz, 1H, CH2),
1.56 ppm (d, J=6.2 Hz, 3H, CH3); m/z (ESI-TOF): calcd for
C10H11NO2H+: 178.0868, found: 178.0864; calcd for C10H11NO2Na+:
4-Hydroxymethyl-3-phenyloxazolidin-2-one (4g): White solid.
1H NMR (CDCl3, 400 MHz): d=7.53–7.37 (m, 4H, ArH), 7.23 (tt, J=
7.3, 1.2 Hz, 1H, ArH), 4.60–4.45 (m, 3H, CH, CH2O), 3.90–3.65(m, 2H,
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ꢀ 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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CH2OH), 1.83 ppm (s, 1H, OH); 13C NMR (CDCl3, 100 MHz): d=156.1,
136.2, 129.3, 125.4, 122.0, 64.4, 60.5, 57.5 ppm. m/z (ESI-TOF): calcd
for C10H11NO3H+: 194.0817, found: 194.0820; calcd for
C10H11NO3Na+: 216.0635, found: 216.0628; calcd for (2ꢁ
C10H11NO3)Na+: 409.1376, found: 409.1375.
3-(4-Methoxyphenyl)-5-methyloxazolidin-2-one (3n):[30,45] White
solid. 1H NMR (CDCl3, 400 MHz): d=7.44 (d, J=9.1 Hz, 2H, ArH),
6.92 (d, J=9.1 Hz, 2H, ArH), 4.84–4.74 (m, 1H, CH), 4.10 (t, J=
8.4 Hz, 1H, CH2), 3.82 (s, 3H, OCH3), 3.61 (dd, J=8.6, 7.1 Hz, 1H,
CH2), 1.54 ppm (d, J=6.2 Hz, 3H, CH3); m/z (ESI-TOF): calcd for
C11H13NO3H+: 208.0974, found: 208.0978; calcd for C11H13NO3Na+:
230.0793, found: 230.0799; calcd for (2ꢁC11H13NO3)Na+: 437.1688,
found: 437.1706.
5-Allyoxymethyl-3-phenyloxazolidin-2-one (3h):[27] Yellow syrup.
1H NMR (CDCl3, 400 MHz): d=7.58 (d, J=8.8 Hz, 2H, ArH), 7.40 (t,
J=7.5 Hz, 2H, ArH), 7.16 (tt, J=7.4, 2.0 Hz, 1H, ArH), 5.90–5.84 (m,
1H, CH=CH2), 5.35–5.21 (m, 2H, CH=CH2), 4.85–4.75 (m, 1H, CH),
4.14–4.06 (m, 3H, CH2, OCH2), 3.97 (dd, J=8.8, 6.3 Hz, 1H, OCH2),
3.77–3.68 ppm (m, 2H, OCH2); m/z (ESI-TOF): calcd for
C13H15NO3H+: 234.1130, found: 234.1132; calcd for C13H15NO3Na+:
256.0950, found: 256.0957; calcd for (2ꢁC13H15NO3)Na+: 489.2002,
found: 489.2022.
3-(4-Fluorophenyl)-5-methyloxazolidin-2-one (3o): White solid.
1H NMR (CDCl3, 400 MHz): d=7.55–7.47 (m, 2H, ArH), 7.14–7.05 (m,
2H, ArH), 4.85–4.76 (m, 1H, CH), 4.12 (t, J=8.4 Hz, 1H, CH2), 3.63
(dd, J=8.6, 7.1 Hz, 1H, CH2), 1.56 ppm (d, J=6.2 Hz, 3H, CH3);
13C NMR (CDCl3, 100 MHz): d=160.4, 158.0, 154.9, 134.5, 120.0(d,
J=5.8 Hz), 115.8(d, J=22.4 Hz), 69.5, 52.4, 20.7 ppm. 19F NMR
(CDCl3): d=À118.7 ppm (s); IR (KBr): n˜ =3080, 2950, 2930, 2889,
1742, 1514, 1403, 1360, 1223, 1119, 1068, 834, 751, 644, 555,
510 cmÀ1. m/z (ESI-TOF): calcd for C10H10FNO2H+: 196.0768, found:
196.0770; calcd for C10H10FNO2Na+: 218.0593, found: 218.0589.
(2-Oxo-3-phenyloxazolidin-5-yl)methyl 4-(tert-butyl)benzoate (3i):
White solid. 1H NMR (CDCl3, 400 MHz): d=7.93 (d, J=8.6 Hz, 2H,
ArH), 7.55 (d, J=7.8 Hz, 2H, ArH), 7.45–7.35 (m, 4H, ArH), 7.15 (tt,
J=7.4, 1.8 Hz, 1H, ArH), 5.03–4.94 (m, 1H, CH), 4.63–4.52 (m, 2H,
CH2), 4.21 (t, J=9.0 Hz, 1H, CH2), 3.94 (dd, J=9.04, 6.0 Hz, 1H,
CH2), 1.32 ppm (s, 9H, CH3); 13C NMR (CDCl3, 100 MHz): d=166.5,
157.9, 155.0, 138.0, 129.8, 129.2, 126.3, 125.7, 124.2, 118.4, 70.5,
64.9, 46.9, 35.8, 31.0 ppm. IR (KBr): n˜ =3065, 3046, 2962, 2906,
2871, 1741, 1717, 1604, 1502, 1408, 1276, 1222, 1124, 1079, 979,
3-(4-Chlorophenyl)-5-methyloxazolidin-2-one (3p):[37] White solid.
1H NMR (CDCl3, 400 MHz): d=7.51 (d, J=9.0 Hz, 2H, ArH), 7.35 (d,
J=9.0 Hz, 2H, ArH), 4.87–4.77 (m, 1H, CH), 4.11 (t, J=8.4 Hz, 1H,
CH2), 3.62 (dd, J=8.6, 7.1 Hz, 1H, CH2), 1.56 ppm (d, J=6.3 Hz, 3H,
CH3); m/z (ESI-TOF): calcd for C10H10ClNO2H+: 212.0478, found:
212.0474; calcd for C10H10ClNO2Na+: 234.0298, found: 234.0293;
calcd for (2ꢁC10H10ClNO2)Na+: 445.0698, found: 445.0693.
850, 774, 750, 705, 686, 669 cmÀ1
. m/z (ESI-TOF): calcd for
C21H23NO4Na+: 376.1525, found: 376.1518; calcd for (2ꢁ
C21H23NO4)Na+: 729.3152, found: 729.3155.
3-(4-Bromophenyl)-5-methyloxazolidin-2-one (3q): Yellow solid.
1H NMR (CDCl3, 400 MHz): d=7.52–7.43 (m, 4H, ArH), 4.86–4.77 (m,
1H, CH), 4.11 (t, J=8.4 Hz, 1H, CH2), 3.61 (dd, J=8.6, 7.1 Hz, 1H,
CH2), 1.56 ppm (d, J=6.2 Hz, 3H, CH3); 13C NMR (CDCl3, 100 MHz):
d=154.7, 137.5, 132.0, 119.6, 116.7, 69.6, 51.7, 20.6 ppm. IR (KBr):
n˜ =3035, 2940, 2870, 1735, 1718, 1685, 1654, 1637, 1590, 1508,
1490, 1414, 1398, 1219, 1126, 1063, 823, 764, 642 cmÀ1. m/z (ESI-
TOF): calcd for C10H10BrNO2H+: 255.9973, found: 255.9969; calcd
for C10H10BrNO2Na+: 277.9793, found: 277.9785.
cis-3-Phenylhexahydrobenzooxazolidin-2-one (3j):[27,44] White solid.
1H NMR (CDCl3, 400 MHz): d=7.51 (d, J=8.6 Hz, 2H, ArH), 7.39 (t,
J=7.4 Hz, 2H, ArH), 7.18 (tt, J=7.4, 1.0 Hz, 1H, ArH), 4.73–4.66 (m,
1H, CH), 4.29 (q, J=6.4 Hz, CH), 2.22–2.10 (m, 1H, CH2), 2.10–1.98
(m, 1H, CH2), 1.90–1.78 (m, 1H, CH2), 1.70–1.50 (m, 4H, CH2), 1.38–
1.25 ppm (m, 1H, CH2); m/z (ESI-TOF): calcd for C13H15NO2Na+:
240.1000, found: 240.1002; calcd for (2ꢁC13H15NO2)Na+: 457.2104,
found: 457.2115.
5-Methyl-3-(4-nitrophenyl)oxazolidin-2-one (3r):[27] Yellow solid.
1H NMR (CDCl3, 400 MHz): d=8.27 (d, J=9.4 Hz, 2H, ArH), 7.74 (d,
J=9.4 Hz, 2H, ArH), 4.94–4.84 (m, 1H, CH), 4.22 (t, J=8.6 Hz, 1H,
CH2), 3.71 (dd, J=8.8, 7.1 Hz, 1H, CH2), 1.60 ppm (d, J=6.3 Hz, 3H,
CH3); m/z (ESI-TOF): calcd for C10H10N2O4H+: 223.0719, found:
223.0712; calcd for C10H10N2O4Na+: 245.0538, found: 245.0535;
calcd for (2ꢁC10H10N2O4)Na+: 467.1180, found: 467.1186.
cis-3-Phenylcyclopenteneoxazolidin-2-one (3k):[28] White solid.
1H NMR (CDCl3, 400 MHz): d=7.57 (d, J=8.9 Hz, 2H, ArH), 7.36–
7.42 (m, 2H, ArH), 7.15 (tt, J=7.4, 2.1 Hz, 1H, ArH), 5.09–5.03 (m,
1H, CH), 4.81–4.73 (m, 1H, CH), 2.25–2.13 (m, 1H, CH2), 2.03–1.95
(m, 1H, CH2), 1.87–1.67 ppm (m, 4H, CH2); 13C NMR (CDCl3,
100 MHz): d=155.2, 137.3, 129.2, 124.2, 119.8, 78.6, 61.1, 34.0, 31.7,
22.2 ppm. IR (KBr): n˜ =2965, 2920, 2850, 1738, 1718, 1701, 1685,
1654, 1637, 1600, 1560, 1541, 1508, 1491, 1458, 1397, 1262, 1093,
1036, 801, 760, 694, 515 cmÀ1
.
m/z (ESI-TOF): calcd for
C12H13NO2Na+: 226.0844, found: 226.0845; calcd for (2ꢁ
C12H13NO2)Na+: 429.1790, found: 429.1799.
Acknowledgements
We gratefully thank financial supports from the National Natural
Science Foundation of China (Grants 21132002, 21372172 and
21402135), the Priority Academic Program Development of Jiang-
su Higher Education Institutions, the Major Research Project of
the Natural Science Foundation of the Jiangsu Higher Education
Institutions (Project 14KJA150007), and the Qing Lan Project.
5,5-Dimethyl-3-phenyloxazolidin-2-one (3l):[27] White solid. 1H NMR
(CDCl3, 400 MHz): d=7.53 (d, J=8.7 Hz, 2H, ArH), 7.37 (t, J=7.4 Hz,
2H, ArH), 7.13 (tt, J=7.4, 2.1 Hz,1H, ArH), 3.77 (s, 2H, CH2),
1.56 ppm (s, 6H, CH3); m/z (ESI-TOF): calcd for C11H13NO2H+:
192.1025, found: 192.1022; calcd for C11H13NO2Na+: 214.0844,
found: 214.0848; calcd for (2ꢁC11H13NO2)Na+: 405.1790, found:
405.1800.
3-(4-Methylphenyl)-5-methyloxazolidin-2-one (3m):[27] White solid.
1H NMR (CDCl3, 400 MHz): d=7.43 (d, J=8.6 Hz, 2H, ArH), 7.19 (d,
J=8.2 Hz, 2H, ArH), 4.85–4.73 (m, 1H, CH), 4.11 (t, J=8.5 Hz, 1H,
CH2), 3.62 (dd, J=8.6, 7.0 Hz, 1H, CH2), 2.35 (s, 3H, CH3), 1.55 ppm
(d, J=6.2 Hz, 3H, CH3); m/z (ESI-TOF): calcd for C11H13NO2H+:
192.1025, found: 192.1024; calcd for C11H13NO2Na+: 214.0844,
found: 214.0850; calcd for (2ꢁC11H13NO2)Na+: 405.1790, found:
405.1802.
Keywords: cycloaddition · heterocycles · rare earths · N,O
ligands · regioselectivity
[1] W. R. Roush, R. A. James, Aust. J. Chem. 2002, 55, 141.
[2] D. J. Ager, I. Prakash, D. R. Schaad, Aldrichimica Acta 1997, 30, 3.
[3] J. A. Demaray, J. E. Thuener, M. N. Dawson, S. J. Sucheck, Bioorg. Med.
Chem. Lett. 2008, 18, 4868.
[4] E. J. Brnardica, M. E. Fraleya, Bioorg. Med. Chem. Lett. 2010, 20, 3129.
&
ChemCatChem 0000, 00, 0 – 0
www.chemcatchem.org
6
ꢀ 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Full Papers
[5] S. I. Fujita, H. Kanamaru, H. Senboku, M. Arai, Int. J. Mol. Sci. 2006, 7,
438.
[6] K. I. Tominaga, Y. Sasaki, Synlett 2002, 2, 0307.
[7] R. Juꢂrez, P. Concepciꢃn, A. Corma, H. Garcꢄa, Chem. Commun. 2010, 46,
4181.
[8] A. W. Miller, S. T. Nguyen, Org. Lett. 2004, 6, 2301.
[9] M. T. Hancock, A. R. Pinhas, Tetrahedron Lett. 2003, 44, 5457.
[10] Y. Wu, L. He, Y. Du, J. Wang, C. Miao, W. Li, Tetrahedron 2009, 65, 6204.
[11] R. A. Watile, D. B. Bagal, K. M. Deshmukh, K. P. Dhake, B. M. Bhanage, J.
Mol. Catal. A 2011, 351, 196.
[37] M. Fujiwara, A. Baba, H. Matsuda, Bull. Chem. Soc. Jpn. 1990, 63, 1069.
[38] C. Kim, S. Y. Ko, Bull. Korean Chem. Soc. 2011, 32, 4450.
[39] K. Lee, S. H. Lee, J. S. Son, S. Y. Ko, S. A. Lee, K. I. Lee, Bull. Korean Chem.
Soc. 2013, 34, 641.
[40] W. J. Irwin, D. L. Wheeler, J. Chem. Soc. C 1971, 3166.
[41] J. E. Herweh, W. J. Kauffman, J. Heterocycl. Chem. 1971, 8, 983.
[42] B. M. Trost, A. R. Sudhakar, J. Am. Chem. Soc. 1987, 109, 3792.
[43] C. Larksarp, H. Alper, J. Am. Chem. Soc. 1997, 119, 3709.
[44] T. Baronsky, C. Beattie, R. W. Harrington, R. Irfan, M. North, J. G. Osende,
C. Young, ACS Catal. 2013, 3, 790.
[12] B. Gabriele, G. Salerno, D. Brindisi, M. Costa, G. P. Chiusoli, Org. Lett.
2000, 2, 625.
[45] R. L. Paddock, D. Adhikari, R. L. Lord, M. H. Baik, S. T. Nguyen, Chem.
Commun. 2014, 50, 15187.
[13] Y. Wang, J. Liu, C. Xia, Chin. J. Catal. 2011, 32, 1782.
[14] J. Liu, X. Peng, J. Liu, S. Zheng, W. Sun, C. Xia, Tetrahedron Lett. 2007,
48, 929.
[15] P. Li, X. Yuan, S. Wang, S. Lu, Tetrahedron 2007, 63, 12419.
[16] F. Li, C. Xia, J. Catal. 2004, 227, 542.
[46] J. Qin, P. Wang, Q. Li, Y. Zhang, D. Yuan, Y. Yao, Chem. Commun. 2014,
50, 10952.
[47] C. Beattie, M. North, Chem. Eur. J. 2014, 20, 8182.
[48] C. Beattie, M. North, ChemCatChem 2014, 6, 1252.
[49] M. B. Dinger, M. J. Scott, Inorg. Chem. 2001, 40, 1029.
[50] C. J. Whiteoak, E. Martin, M. M. Belmonte, J. B. Buchholz, A. W. Kleij, Adv.
Synth. Catal. 2012, 354, 469.
[17] S. Pulla, V. Unnikrishnan, P. Ramidi, S. Z. Sullivan, A. Ghosh, J. L. Dallas, P.
Munshi, J. Mol. Catal. A 2011, 338, 33.
[18] S. R. Jagtapa, Y. P. Patila, S. Fujitab, M. Araib, B. M. Bhanagea, Appl. Catal.
A 2008, 341, 133.
[51] Y. Kim, J. G. Verkade, Organometallics 2002, 21, 2395.
[52] Y. Kim, P. N. Kapoor, J. G. Verkade, Inorg. Chem. 2002, 41, 4834.
[53] Y. Kim, G. K. Jnaneshwara, J. G. Verkade, Inorg. Chem. 2003, 42, 1437.
[54] A. J. Chmura, C. J. Chuck, M. G. Davidson, M. D. Jones, M. D. Lunn, S. D.
Bull, M. F. Mahon, Angew. Chem. Int. Ed. 2007, 46, 2280; Angew. Chem.
2007, 119, 2330.
[55] C. Redshaw, M. A. Rowan, D. M. Homden, S. H. Dale, M. R. J. Elsegood, S.
Matsui, S. Matsuura, Chem. Commun. 2006, 3329.
[56] T. R. Dargaville, P. J. D. Bruyn, A. S. C. Lim, M. G. Looney, A. C. Potter,
D. H. Solomon, X. Q. Zhang, Chemistry of Novolac Resins 1997, 1389.
[57] H. Wang, I. D. Kozekov, T. M. Harris, C. J. Rizzo, J. Am. Chem. Soc. 2003,
125, 5687.
[58] W. R. Roush, M. A. Adam, J. Org. Chem. 1985, 50, 3752.
[59] W. J. Farrissey, Jr., A. M. Nashu, J. Heterocycl. Chem. 1970, 7, 331.
[60] P. H. J. Carlsen, H. S. H. Gautun, Tetrahedron: Asymmetry 1995, 6, 1667.
[61] J. Routier, M. Calancea, M. David, Y. Vallꢅe, J.-N. Denis, Eur. J. Org. Chem.
2008, 5687.
[19] R. Morales-Nava, M. F. Zertuche, M. OrdꢃÇez, Molecules 2011, 16, 8803.
[20] G. P. Speranza, W. J. Peppel, J. Org. Chem. 1958, 23, 1922.
[21] L. Aroua, A. Baklouti, Synth. Commun. 2007, 37, 1935.
[22] J. E. Herweh, W. J. Kauffman, Tetrahedron Lett. 1971, 12, 809.
[23] J. E. Herweh, J. Heterocycl. Chem. 1968, 5, 687.
[24] J. E. Herweh, T. A. Foglia, D. Swern, J. Org. Chem. 1968, 33, 4029.
[25] H. Siegel, H. Wittmann, Monatsh. Chem. 1982, 113, 1005.
[26] X. Zhang, W. Chen, C. Zhao, C. Li, X. Wu, W. Z. Chen, Synth. Commun.
2010, 40, 3654.
[27] I. Shibata, A. Baba, H. Iwasaki, H. Matsuda, J. Org. Chem. 1986, 51, 2177.
[28] M. Fujiwara, A. Baba, Y. Tomohisa, H. Matsuda, Chem. Lett. 1986, 1963.
[29] A. Baba, K. Seki, H. Matsuda, J. Heterocycl. Chem. 1990, 27, 1925.
[30] K. Yano, N. Amishiro, A. Baba, H. Matsuda, Bull. Chem. Soc. Jpn. 1991,
64, 2661.
[31] C. Qian, D. Zhu, Synlett 1994, 129.
[32] H. Y. Wu, J. C. Ding, Y. K. Liu, J. Indian Chem. Soc. 2003, 80, 36.
[33] M. T. Barros, A. M. F. Phillips, Tetrahedron: Asymmetry 2010, 21, 2746.
[34] I. Javni, A. Guo, Z. S. Petrovic, J. Am. Oil Chem. Soc. 2003, 80, 595.
[35] A. Baba, M. Fujiwara, H. Matsuda, Tetrahedron Lett. 1986, 27, 77.
[36] M. Fujiwara, A. Baba, H. Matsuda, J. Heterocycl. Chem. 1988, 25, 1351.
Received: December 12, 2014
Revised: January 16, 2015
Published online on && &&, 0000
ChemCatChem 0000, 00, 0 – 0
www.chemcatchem.org
7
ꢀ 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
These are not the final page numbers! ÞÞ

FULL PAPERS
P. Wang, J. Qin, D. Yuan,* Y. Wang,
Y. Yao*
&& – &&
Synthesis of Oxazolidinones from
Epoxides and Isocyanates Catalyzed
by Rare-Earth-Metal Complexes
Does Kepler-186f count as a rare
earth? Rare-earth-metal complexes
stabilized by an amino-bridged tri-
phenolate ligand are highly active in
catalyzing the cycloaddition of isocya-
nates and epoxides. Under mild condi-
tions, various terminal and disubstituted
epoxides as well as arylisocyanates are
transformed into corresponding oxazoli-
dinones with moderate to good yields
and good regio- and stereoselectivity.
&
ChemCatChem 0000, 00, 0 – 0
www.chemcatchem.org
8
ꢀ 0000 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!