Transition-metal-catalyzed reactions of propargylamine with carbon dioxide and carbon disulfide

Article abstract of DOI:10.1021/jo0014966

The reactions of propargylamine derivatives with carbon dioxide and carbon disulfide have been systematically examined in the presence of transition-metal catalysts. Pd(OAc)₂ is the best catalyst for the formation of the corresponding oxazolidinones. In addition, we found that, in the reaction of propargylamine with carbon dioxide catalyzed by palladium (0) metal catalyst in toluene, both oxazolidinone 1 and imidazolidinone 2 could be obtained under mild reaction conditions at the same time. The reaction of 1 with primary and secondary amines has been examined. A plausible reaction mechanism for the formation of 2 was proposed. In addition, in this paper, we first disclosed the ligand's effect on this reaction. Using PBu^t₃ as a ligand with Pd₂(dba)₃, 1 was exclusively formed in 90% yield.

Full text of DOI:10.1021/jo0014966

16
J . Org. Chem. 2002, 67, 16-21
Tr a n sition -Meta l-Ca ta lyzed Rea ction s of P r op a r gyla m in e w ith
Ca r bon Dioxid e a n d Ca r bon Disu lfid e
Min Shi* and Yu-Mei Shen
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry,
Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
mshi@pub.sioc.ac.cn
Received October 19, 2000
The reactions of propargylamine derivatives with carbon dioxide and carbon disulfide have been
systematically examined in the presence of transition-metal catalysts. Pd(OAc)2 is the best catalyst
for the formation of the corresponding oxazolidinones. In addition, we found that, in the reaction
of propargylamine with carbon dioxide catalyzed by palladium(0) metal catalyst in toluene, both
oxazolidinone 1 and imidazolidinone 2 could be obtained under mild reaction conditions at the
same time. The reaction of 1 with primary and secondary amines has been examined. A plausible
reaction mechanism for the formation of 2 was proposed. In addition, in this paper, we first disclosed
the ligand’s effect on this reaction. Using PBut3 as a ligand with Pd2(dba)3, 1 was exclusively formed
in 90% yield.
Carbon dioxide is the earth’s most abundant carbon
compounds and their unsaturated derivatives,13 such as
â-oxopropyl carbonates,14 furanones,15 dihydrofuranones,16
cyclic carbamates,17 and keto alcohols.4
resource and is used by green plants and anaerobic
bacteria for chemicals production on a massive scale. In
contrast, man’s industrial and laboratory utilization of
CO2 as a chemical feedstock is miniscale. During the last
two decades of the twentieth century, the chemistry of
carbon dioxide has received much attention from the
viewpoint of carbon resources and environmental prob-
lems.1 In particular, fixation of CO2 by transition-metal
catalysts has made significant progress. One of the major
successes is the utilization of propargylic alcohol deriva-
tives and carbon dioxide as the starting materials to
prepare cyclic carbonate in the presence of a metal
catalyst such as ruthenium,2 cobalt,3 palladium,4-6
copper,7-11 or phosphine compounds.12 This strategy is
fundamentally based on the cyclization of the propargylic
carbonate species into the corresponding R-alkylidene
cyclic carbonate in the presence of metal catalyst. These
cyclic carbonates are useful intermediates for the syn-
thesis of functional carbamates, esters, or oxazolidinone
However, until now we only found two reports related
with the reaction of N-substituted propargylamines with
CO2 to give oxazolidinones in moderate yields: (1) the re-
action of N-substituted propargylamines with carbon di-
oxide in the presence of a (η4-1,5-cyclooctadiene)(η6-1,3,5-
cyclooctatriene)ruthenium [Ru(COD)(COT)] catalyst and
tertiary phosphine;18 (2) base-catalyzed direct introduc-
tion of CO2 into acetylenic amines.19 The reaction of N-
unsubstituted propargylamine with carbon dioxide has
not been investigated so far, although the reaction mech-
anism should be very similar to that of propargylic alco-
hol.
Herein, we wish to report an unprecedented Pd(0)-
catalyzed reaction of N-unsubstituted and N-substituted
propargylamine with carbon dioxide. During our own
investigations, we found that both oxazolidinone 1 and
imidazolidinone 2 could be obtained in moderate yield
(40%) at the same time from the Pd(PPh3)4 (5 mol %)
catalyzed reaction of propargylamine with carbon dioxide
under mild reaction conditions (Scheme 1, Table 1, entry
1). The scope and limitations of catalysts and reaction
conditions have been carefully examined. Their results
are summarized in Table 1. The reaction temperature
and time and the pressure of CO2 are important factors
* To whom correspondence should be addressed. Fax: 86-21-
64166128.
(1) (a) Haruki, E.; Ito, T.; Yamamoto, A.; Yamazaki, N.; Higashi,
F.; Inoue, S. In Organic and Bio-oganic Chemistry of Carbon dioxide;
Inore, S., Yamazaki, N., Eds.; Kodansha Ltd.: Tokyo, J apan, 1982.
(b) Keim, W. In Carbon dioxide as a Source of Carbon; Aresta, M.,
Forti, G., Eds.; NATO ASI Series; Pub. Comp.: Dordrecht, 1986; Vol.
206.
(2) Sasaki, Y. Tetrahedron Lett. 1986, 27, 1573.
(3) Inoue, Y.; Ishikawa, J .; Taniguchi, M.; Hashimoto, H. Bull. Chem.
Soc. J pn. 1987, 60, 1204.
(4) Iritani, K.; Yanagihara, N.; K. Utimoto, J . Org. Chem. 1986, 51,
5499.
(5) Inoue, Y.; Itoh, Y.; Yen, I.-F.; Imaizumi, S. J . Mol. Catal. 1990,
60, L1.
(6) Uemura, K.; Shiraishi, D.; Nozori, M.; Inoue, Y. Bull. Chem. Soc.
J pn. 1999, 72, 1063.
(7) Laas, H.; Nissen, A.; Nurrenbach, A. Synthesis 1981, 958.
(8) Dimroth, P.; Pasedach, H. Ger. 1961, 1098953.
(9) Dimroith, P.; Pasedach, H. Chem. Abstr. 1962, 56, P2453a.
(10) Dimroth, P.; Schefczik, E.; Pasedach, H. Ger. 1963, 1145632.
(11) Dimroth, P.; Schefczik, E.; Pasedach, H. Chem. Abstr. 1963,
59, P6412a.
(13) Aresta, M.; Forti, G. In Carbon dioxide as a Source of Carbon;
Reicel, D., Eds.; NATO Asi Series; Pub. Comp.: Dordrecht, 1987; pp
23-31.
(14) J oumier, J . M.; Bruneau, C.; Dixneuf, P. H. J . Chem. Soc.,
Perkin Trans. 1 1993, 1749.
(15) Inoue, Y.; Ohuchi, K.; Yen, I.-F.; Imaizumi, S. Bull. Chem. Soc.
J pn. 1989, 62, 3518.
(16) Inoue, Y.; Matsushita, K.; Yen, I.-F.; Imaizumi, S. Chem. Lett.
1991, 1377.
(17) Ohe, K.; Matsuda, H.; Ishihara, T.; Ogoshi, S.; Chatani, N.;
Murai, S. J . Org. Chem. 1993, 58, 1173.
(18) Mitsudo, T.-A.; Hore, Y.; Yamakawa, Y.; Watanabe, Y. Tetra-
hedron Lett. 1987, 28, 4417.
(19) (a) Costa, M.; Chiusoli, G. P.; Rizzardi, M. J . Chem. Soc., Chem.
Commun. 1996, 1699. (b) Costa, M.; Chiusoli, G. P.; Taffurelli, D.;
Dalmonego, G. J . Chem. Soc., Perkin Trans. 1 1998, 1541.
(12) J oumier, J . M.; Fournier, J .; Bruneau, C.; Dixneuf, P. H.; J .
Chem. Soc., Perkin Trans. 1 1991, 3271.
10.1021/jo0014966 CCC: $22.00 © 2002 American Chemical Society
Published on Web 11/27/2001

Transition-Metal-Catalyzed Reactions of Propargylamine
J . Org. Chem., Vol. 67, No. 1, 2002 17
Ta ble 2. Liga n d Effects in th e Rea ction of
P r op a r gyla m in es w ith Ca r bon Dioxid e
Sch em e 1
Ta ble 1. Rea ction s of P r op a r yla m in e w ith Ca r bon
Dioxid e in th e P r esen ce of P d Ca ta lyst
yieldb (%)
pressure
entry
catalysta
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd2(dba)3
Pd(OAc)2
(kg/cm2) T (°C) time (h)
1
2
1
2
3
4
5
6
7
8
9
1
40
40
40
40
40
40
40
40
20
20
60
20
20
20
20
20
20
60
24
24
60
24
24
24
24
24
trace 20
35
7
8
8
36
32
8
36
85
0
RuH4(PPh3)2
IrCl(CO)(PPh3)2
NiBr2(PPh3)2
trace
trace
0
0
a
Isolated yield.
0
Sch em e 3
a
b
0.5 equiv of catalyst. Isolated yield.
Sch em e 2
Ta ble 3. Rea ction of P r op a r gyla m in e w ith CO2 in th e
P r esen ce of P d II Ca ta lyst
to affect the selectivity of 1 and 2. For example, the yield
of 2 increased as the reaction temperature rising or if
the reaction time was prolonged from 24 to 60 h (Table
1, entries 3 and 4). When the reaction was carried out
under high pressure of CO2 (40 kg/cm2) for 24 h at room
temperature, 1 could be obtained as the major product
in 30% yield, along with the formation of 4% of 2. These
results suggested that 2 might be derived from the
further reaction of 1 with propargylamine. Using Pd2-
(dba)3 (5 mol %) as a catalyst, the similar result was
obtained (Table 1, entry 5). However, in the presence of
Pd(OAc)2 (5 mol %), 1 was obtained as a sole product in
very good yield (Table 1, entry 6). By means of ruthenium
[RuH4(PPh3)2], Vaska-type complex [IrCl(CO)(PPh3)2], or
nickel catalyst [NiBr2(PPh3)2] (Table 1, entries 7-9),
oxazolidinone 1 was produced in very low yield under the
same reaction conditions. Only Pd catalysts [Pd(0) or Pd-
(II)] have catalytic activity for the reaction of propargy-
lamine with CO2. The structures of 1 and 2 were
determined by spectroscopic data and microanalyses.
Furthermore, the crystal structures of 1 and 2 were
unambiguously disclosed by X-ray analyses.
a
Isolated yield.
Sch em e 4
This is a very novel case in the palladium-catalyzed
fixation of CO2 reaction.
To improve the yields of 1 and 2 and clarify the
selectivity of 1 and 2 in the presence of Pd(0) catalyst,
we examined the ligand’s effect in this reaction. Surpris-
ingly, we found that, using ethylenebis(diphenylphos-
phine), tributyphosphine, tri(tert-butyl)phosphine, or 2,2′-
bipyridine (6 mol %) as ligand with Pd2(dba)3 (5 mol %),
the yield of 1 can be significantly improved, along with
only a trace amount of 2 (Scheme 2, Table 2, entries 1-4).
For other propargylamines including N-benzyl-substi-
tuted propargylamine, Pd(0) catalyst showed no activity.
But when Pd(OAc)2 was used as a catalyst, high yields
of cyclic carbamates (3-6) were obtained as the sole
product (Scheme 3, Table 3). The internal alkyne gave
many unidentified products under the same conditions
(Scheme 4). Thus, we explored a very useful chemical
process for the preparation of oxazolidinones from pro-
pargylamine derivatives with CO2 in the presence of Pd
catalysts.
In particular, when tri(tert-butyl)phosphine (PBut ) was
3
used as a ligand, the yield of 1 could reach 90% without
formation of 2 (Table 2, entry 4). The combination of Pd-
(OAc)2 (5 mol %) with tri(tert-butyl)phosphine (5 mol %)
gave 81% of 1 (Table 2, entry 5). Concerning the tri(tert-
butyl)phosphine ligand’s effect, Fu also reported recently
its significant effect in the Suzuki coupling reaction.20
(20) (a) Littke, A. F.; Dai, C.; Fu, G. C. J . Am. Chem. Soc. 2000,
122, 4020. (b) Hundertmark, T.; Littke, A. F.; Buchwald, S. L.; Fu, G.
C. Org. Lett. 2000, 2, 1729.

18 J . Org. Chem., Vol. 67, No. 1, 2002
Shi and Shen
Sch em e 5
Sch em e 7
Ta ble 4. P r ep a r a tion of En ol Ur eth a n es fr om th e
Rea ction of Ca r ba m a te 1 w ith P r im a r y Am in es in th e
P r esen ce of P d (P P h 3)4 (0.1 Equ iv) in Tolu en e a t Room
Tem p er a tu r e
Ta ble 5. P r ep a r a tion of Ur eth a n es fr om th e Rea ction of
Ca r ba m a te 1 w ith Secon d a r y Am in es in Tolu en e a t Room
Tem p er a tu r e
a
Isolated yield.
Sch em e 6
a
Isolated yield.
Sch em e 8
To the best of our knowledge, the formation of imida-
zolidinone 2 from the fixation of CO2 with propargy-
lamine has never been reported before. Only Murai
reported that palladium-catalyzed reaction of 5-methyl-
ene-1,3-dioxolan-2-ones with aromatic isocyanates un-
derwant cycloaddition to give the corresponding oxazo-
lidinones in good yields together with cyclic ureas.17 To
gain more mechanistic insights into this novel reaction,
we directly carried out the reaction of 1 with propargy-
lamine or some other amines, such as butylamine,
propenylamine, and cyclohexylamine, respectively, in
toluene under the same reaction conditions (Scheme 5).
We found that the corresponding imidazolidinons 2, 7,
8, and 9 were obtained in moderate yields as well (Table
4). No reactions occurred without Pd(0) catalyst. How-
ever, the reaction of 1 with benzylamine (PhCH2NH2) or
phenethylamine [PhCH(CH3)NH2] gave very complicated
products under the same reaction conditions. On the
basis of these results shown in Table 4, it is very clear
that the imidazolidinone 2 was in fact formed from the
further Pd(0)-catalyzed reaction of 1 with propargy-
lamine, and a novel reaction process for the preparation
of imidazolidinones from oxazolidinones 1 has been
explored.
On the other hand, in the reactions of 1 with secondary
amines, the ring-opened products 10-13 were obtained
quantitatively even without palladium catalyst (Scheme
7, Table 5). Using 3 as a substrate in the reaction with
primary amine (cyclohexylamine), we found that the
corresponding cyclic urethane 14 was obtained in only
2% yield under the same conditions (Scheme 8). In
addition, in the reactions of 3 with secondary amines,
the ring-opened products 15-17 were formed in moderate
yields as well (Scheme 9, Table 6).
Based on these investigations, we tentatively proposed
a plausible mechanism for the formation of 2, 7-9, and
14 in Scheme 10. The oxazolidinone 1 undergoes a
palladium(0)-catalyzed amination reaction of olefin with
primary amines to form the intermediate I, and then the
amine adds to the carbonyl group of intermediate I via
an intramolecular attacking process giving the interme-
diate II. Dehydration of the intermediate II affords the
intermediate III, which produces the final product by
It should be emphasized here that, as shown in Scheme
6, for 2-oxazolidione, no reaction occurred with primary
amines even in the presence of Pd(0) catalyst. This result
suggested that, the olefinic moiety in 2-oxazolidione
derivatives must be required for the further reactions of
oxazolidinones with primary amines to give the corre-
sponding imidazolidinones.

Transition-Metal-Catalyzed Reactions of Propargylamine
J . Org. Chem., Vol. 67, No. 1, 2002 19
Sch em e 9
Sch em e 11
Ta ble 6. P r ep a r a tion of Ur eth a n es fr om th e Rea ction of
Ca r ba m a te 1 w ith Secon d a r y Am in es in Tolu en e a t Room
Tem p er a tu r e
Ta ble 7. Rea ction of P r op a r gyla m in e w ith CS2 in th e
P r esen ce of P d (0) Ca ta lyst
a
Isolated yield.
In conclusion, the reactions of propargylamine deriva-
tives with carbon dioxide and carbon disulfide have been
systematically examined in the presence of transition
metal catalysts. Pd(OAc)2 (5 mol %) is the best catalyst
for the formation of the corresponding oxazolidinones. We
found that oxazolidinones 1 and imidazolidinones 2 could
be obtained from the reaction of propargylamine with
carbon dioxide in the presence of a catalytic amount of
Pd(0) metal-tertiary phosphine system in toluene. Either
1 or 2 can be obtained as the major product by changing
the reaction conditions. A novel transition-metal-cata-
lyzed reaction for the formation of imidazolidinones 2-5
was explored from reactions of 1 with proparylamines,
butylamine propenylamine, and cyclohexylamines under
mild reaction conditions. Efforts are underway to eluci-
date the mechanistic details of this reaction and to
identify systems enabling the similar carboxylation of
other substrates and subsequent transformation thereof.
a
Isolated yield.
Sch em e 10
Exp er im en ta l Section
reductive elimination and regenerate the palladium(0)
catalyst. For secondary amines, owing to their high
nucleophilicities, the direct attacking to the carbonyl
group of 1 can take place to give the corresponding ring-
opened product 10-13. In the reaction of oxazolidinone
3 with primary amine, its sterical bulkiness might block
out the palladium(0)-catalyzed amination of olefin to give
the corresponding imidazolidinone in very low yield. Its
sterical bulkiness also caused the relatively low yields
of 15-17 in the reaction of 3 with secondary amines by
comparison of the reactions of 1 with secondary amines
(Table 5).
Moreover, we also examined the reaction of propargy-
lamine with carbon disulfide, an analogue of carbon
dioxide, under the same reaction conditions. For prop-
argylamine, the reaction proceeded very well in the
presence of Pd(0) (5 mol %) catalyst to give 18 in 99%
yield at room temperature (Scheme 11, Table 7, entry
1). But for 1,1-diethylpropargylamine and N-benzylpro-
pargylamine, the reaction required to be carried out at
higher temperature to give 19 and 20 in moderate yields,
respectively (Scheme 11).
Gen er a l Meth od s. Melting points are uncorrected. 1H and
13C NMR spectra were recorded at 300 and 75 MHz, respec-
tively. Coupling constants (J ) are reported in hertz. Mass
spectra were recorded by EI methods, and HRMS was mea-
sured on a Finnigan MA+ mass spectrometer. Organic solvents
used were dried by standard methods when necessary. All solid
compounds reported in this paper gave satisfactory CHN
microanalyses. Commercially obtained reagents were used
without further purification. All reactions were monitored by
TLC with Huanghai GF254 silica gel coated plates. Flash
column chromatography was carried out using 300-400 mesh
silica gel at increased pressure.
Gen er a l P r oced u r e for th e F or m a tion of Oxa zolid i-
n on es 1 a n d Im id a zolid in on es 2. F or m a tion of 1. To a
solution of propargylamine (550 mg, 10 mmol) in anhydrous
toluene (20 mL) was added a catalytic amount of Pd(PPh3)4
(58 mg, 0.05 mmol), and the reaction mixture was stirred at
room temperature under carbon dioxide atmosphere (40 kg/
cm2) for 24 h. The solvent was removed under reduced
pressure, and the residue was purified by silica gel column
chromatography (eluent: petroleum ether/EtOAc ) 1/4) to give
1 as a white solid. This solid was further recrystallized from
dichloromethane/petroleum ether ) 1/4 to afford a crystal: 350
mg, 35%; mp 50-52 °C; IR (CHCl3) ν 1780 cm-1 (CdO); 1H

20 J . Org. Chem., Vol. 67, No. 1, 2002
Shi and Shen
NMR (300 MHz, CDCl3, TMS) δ 4.20 (2H, dd, J ) 2.1 1.0, CH2),
4.31 (1H, dd, J ) 2.9 2.1, CH2), 4.78 (1H, dd, J ) 2.1 2.1, CH2),
5.77 (1H, s, NH); 13C NMR (75 MHz, CDCl3, TMS) δ 44.35,
86.86, 151.34, 157.64 (CdO); MS (EI) m/z 100 (100) (MH)+,
71 (24.71) (M+ - 28), 43 (66.17) (M+ - 56); HRMS (EI) m/z
99.0321, C4H5NO2 requires M, 99.0320. Anal. Calcd for C4H5-
NO2: C, 48.48, H, 5.05, N, 14.14. Found: C, 48.39, H, 5.03, N,
14.15.
1.40-1.26 (2H, m, CH2), 1.56-1.64 (2H, m, CH2), 2.06 (3H, s,
CH3), 3.58 (2H, t, J ) 7.3, CH2), 5.99 (1H, s, CH), 9.98 (1H, s,
NH); 13C NMR (75 MHz, CDCl3, TMS) δ 10.37, 13.79, 20.05,
31.87, 40.64, 103.92, 119.52, 154.91 (CdO); MS (EI) m/z 154
(51.45) (M+), 98 (64.60) (M+ - 56), 73 (100) (M+ - 81), 44
(89.04) (M+ - 110); HRMS (EI) m/z 154.1117, C8H13N2O
requires M, 154.1106.
F or m a tion of 8. This compound was obtained as a colorless
oil in the same manner as that described above using 1 (100
mg, 1.0 mmol), propenylamine (63 mg, 1.10 mmol), and Pd-
(PPh3)4 (5.8 mg, 0.005 mmol): 86 mg, 62%; IR (CHCl3) ν 1714
F or m a tion of 2. This compound was obtained as a white
solid in the same manner as that described above using
propargylamine (550 mg, 10 mmol) and a catalytic amount of
Pd(PPh3)4 (58 mg, 0.05 mmol) at 60 °C: 490 mg, 36%; mp 122-
1
cm-1 (CdO); H NMR (300 MHz, CDCl3, TMS) δ 2.01 (3H, s,
1
124 °C; IR (CHCl3) ν 1682 cm-1 (CdO); H NMR (300 MHz,
CH3), 4.25 (2H, dd, J ) 2.6 2.0, CH2), 5.08 (1H, dd, J ) 15.9
1.0, CH), 5.17 (1H, d, J ) 10.3, CH), 5.82-5.95 (1H, m, CH),
6.02 (1H, s, CH), 9.65 (1H, s, NH); 13C NMR (75 MHz, CDCl3,
TMS) δ 20.21, 42.69, 103.98, 116.12, 119.90, 133.30, 154.77
(CdO); MS (EI) m/z 138 (100) (M+), 97 (69.99) (M+ - 41), 56
(40.14) (M+ - 82), 41 (47.26) (M+ - 97); HRMS (EI) m/z
138.0796, C7H10N2O requires M, 138.0793.
CDCl3, TMS) δ 2.14 (3H, s, CH3), 2.24 (1H, dd, J ) 2.6 2.2,
CH), 4.42 (2H, d, J ) 2.6, CH2), 6.02 (1H, s, CH), 9.90 (1H, s,
NH); 13C NMR (75 MHz, CDCl3, TMS) δ 10.22, 29.87, 71.87,
78.26, 104.43, 119.44, 154.33 (CdO); MS (EI) m/z 136 (100)
(M+), 97 (63.98) (M+ - 39), 42 (28.98) (M+ - 94). Anal. Calcd
for C7H8N2O: C, 61.76, H, 5.88, N, 20.59. Found: C, 61.66, H,
6.14, N, 20.67.
F or m a tion of 9. This compound was obtained as a white
solid in the same manner as that described above using 1 (100
mg, 1.0 mmol), cyclohexylamine (109 mg, 1.10 mmol), and Pd-
(PPh3)4 (5.8 mg, 0.005 mmol): 97 mg, 54%; mp 100-102 °C;
IR (CHCl3) ν 1714 cm-1 (CdO); 1H NMR (300 MHz, CDCl3,
TMS) δ 1.28-2.18 (10H, m, cyclohexyl), 2.23 (3H, s, CH3),
F or m a tion of 3. This compound was obtained as a colorless
oil in the same manner as that described above using 1,1-
diethylpropargylamine (1.10 g, 10 mmol), but using Pd(OAc)2
(110 mg, 0.05 mmol) as a catalyst: 1.32 g, 85%; IR (CHCl3) ν
1777 cm-1 (CdO); 1H NMR (300 MHz, CDCl3, TMS) δ 0.94
(6H, t, J ) 7.4 Hz, CH3), 1.50-1.80 (4H, m, CH2), 4.13 (1H, d,
J ) 3.3, CH), 4.76 (1H, d, J ) 3.3, CH), 5.97 (1H, s, NH); 13C
NMR (75 MHz, CDCl3, TMS) δ 7.68, 33.13, 65.95, 84.91,
156.57, 159.01 (CdO); MS (EI) m/z 155 (7.8) (M+), 126 (100)
(M+ - 29), 112 (9.7) (M+ - 43); HRMS (EI) m/z 155.0935,
C8H13NO2 requires M, 155.0946.
3.96-4.04 (1H, m, CH), 6.09(1H, s, CH), 9.58 (1H, s, NH); 13
C
NMR (75 MHz, CDCl3, TMS) δ 11.96, 25.33, 26.23, 31.10,
53.38, 104.33, 119.62, 156.01 (CdO); MS (EI) m/z 180 (19.77)
(M+), 98 (85.96) (M+ - 82), 56 (100) (M+ - 124), 43 (88.78)
(M+ - 137); HRMS (EI) m/z 180.1267, C10H16N2O requires M,
180.1263.
F or m a tion of 4. This compound was obtained as a colorless
oil in the same manner as that described above using 1-ethy-
nylcyclohexylamine (1.23 g, 10 mmol), but using Pd(OAc)2 (110
mg, 0.05 mmol) as a catalyst: 0.84 g, 50%; IR (CHCl3) ν 1774
cm-1 (CdO); 1H NMR (300 MHz, CDCl3, TMS) δ 1.20-1.40
(2H, m, CH2), 1.40-1.80 (4H, m, CH2), 1.80-2.0 (4H, m, CH2),
4.23 (1H, d, J ) 3.3, CH), 4.66 (1H, d, J ) 3.3 Hz, CH), 8.0
(1H, s, NH); 13C NMR (75 MHz, CDCl3, TMS) δ 7.41, 25.45,
26.19, 28.58, 34.10, 52.54, 79.06, 150.23, 162.30 (CdO); MS
Gen er a l P r oced u r e for th e Rea ction of Oxa zolid in o-
n es 1 w ith Secon d a r y Am in es. F or m a tion of 10. To a
solution of 1 (40 mg, 0.40 mmol) in anhydrous toluene (10 mL)
was added diethylamine (32 mg, 0.44 mmol), and the reaction
mixture was stirred at room temperature for 24 h. The solution
was removed under reduced pressure, and the residue was
purified by silica gel column chromatography (eluent: petro-
leum ether/ EtOAc )1/4) to give 10 as a viscous oily com-
pound: 69 mg, 98%; IR (CHCl3) ν 1721 cm-1 and 1784 (CdO);
1H NMR (300 MHz, CDCl3, TMS) δ 1.10 (6H, t, J ) 7.2 Hz,
CH3), 2.16 (3H, s, CH3), 3.25 (4H, q, J ) 7.2 Hz, CH2), 4.12
(2H, d, J ) 4.4 Hz, CH2), 5.15 (1H, s, NH); 13C NMR (75 MHz,
CDCl3, TMS) δ 13.68, 27.18, 41.53, 51.42, 166.10 (CdO), 204.82
(CdO); MS (EI) m/z 172 (4.13) (M+), 129 (46.71) (M+ - 43),
100 (100) (M+ - 72), 72 (65.24) (M+ - 100); HRMS (EI) m/z
172.1222, C8H16N2O2 requires M, 172.1212.
F or m a tion of 11. This compound was obtained as a viscous
oily product in the same manner as that described above using
1 (40 mg, 0.4 mmol) and diisopropylamine (44 mg, 0.44
mmol): 78 mg, 98%; IR (CHCl3) ν 1714 cm-1 (CdO); 1H NMR
(300 MHz, CDCl3, TMS) δ 1.24 (12H, d, J ) 7.0 Hz, CH3), 2.18
(3H, s, CH3), 3.90 (2H, qu, J ) 7.0 Hz, CH2), 4.18 (2H, d, J )
4.2 Hz, CH2), 5.11 (1H, s, NH); 13C NMR (75 MHz, CDCl3,
TMS) δ 20.93, 27.08, 45.56, 51.45, 156.58 (CdO), 204.61 (Cd
O); MS (EI) m/z 200 (15.62) (M+), 185 (42.23) (M+ - 15), 128
(80.54) (M+ - 72), 86 (100) (M+ - 114); HRMS (EI) m/z
200.1531, C10H20N2O2 requires M, 200.1525.
(EI) m/z 167 (58) (M+), 139 (40) (M+ - 28), 124 (100) (M+
-
43); HRMS (EI) m/z 167.0944, C9H13NO2 requires M, 167.0946.
F or m a tion of 5. This compound was obtained as a colorless
oil in the same manner as that described above using N-
benzylpropargylamine (1.45 g, 10 mmol), but using Pd(OAc)2
(110 mg, 0.0 5 mmol) as a catalyst: 1.50 g, 80%; IR (CHCl3) ν
1784 cm-1 (CdO); 1H NMR (300 MHz, CDCl3, TMS) δ 4.02
(2H, t, J ) 2.4 Hz, CH2), 4.22-4.25 (1H, m, CH), 4.47 (2H, s,
CH2), 4.72-4.75 (1H, m, CH), 7.20-7.40 (5H, m, Ar); 13C NMR
(75 MHz, CDCl3, TMS) δ 47.18, 47.78, 86.66, 128.10, 128.18,
128.91, 134.94, 148.94, 155.59 (CdO); MS (EI) m/z 189 (13)
(M+), 91 (100) (M+ - 98), 65 (12) (M+ - 124); HRMS (EI) m/z
189.0789, C11H11NO2 requires M, 187.0790.
F or m a tion of 6. This compound was obtained as a colorless
oil in the same manner as that described above using N-(3-
phenylpropyl)propargylamine (1.73 g, 10 mmol), but using Pd-
(OAc)2 (110 mg, 0.0 5 mmol) as a catalyst: 1.52 g, 70%; IR
(CHCl3) ν 1781 cm-1 (CdO); 1H NMR (300 MHz, CDCl3, TMS)
δ 1.88 (2H, quint, J ) 7.6 Hz, CH2), 2.65 (2H, t, J ) 7.6 Hz,
CH2), 3.33 (2H, t, J ) 7.6 Hz, CH2), 4.12 (2H, t, J ) 2.7 Hz,
CH2), 4.28 (1H, dd, J ) 4.4, 2.0 Hz, CH2), 4.72 (1H, dd, J )
4.4, 2.0 Hz, CH2), 7.20-7.40 (5H, m, Ar); 13C NMR (75 MHz,
CDCl3, TMS) δ 28.63, 32.64, 43.22, 47.56, 86.21, 125.94, 128.09,
128.30, 140.68, 148.95, 155.38 (CdO); MS (EI) m/z 217 (82)
(M+), 174 (23) (M+ - 43), 91 (100) (M+ - 126); HRMS (EI) m/z
217.1112, C13H15NO2 requires M, 217.1103.
F or m a tion of 12. This compound was obtained as a viscous
oily product in the same manner as that described above using
1 (40 mg, 0.4 mmol) and dibutylamine (57 mg, 0.44 mmol):
88 mg, 97%; IR (CHCl3) ν 1721 cm-1 (CdO); 1H NMR (300
MHz, CDCl3, TMS) δ 1.10 (6H, t, J ) 7.2 Hz, CH3), 1.20-1.35
(2H, m, CH2), 1.40-1.52 (2H, m, CH2), 2.18 (3H, s, CH3), 3.15
(4H, t, J ) 7.2 Hz, CH2), 4.12 (2H, d, J ) 4.38, CH2), 5.15 (1H,
s, NH); 13C NMR (75 MHz, CDCl3, TMS) δ 13.81, 20.13, 27.11,
30.61, 47.11, 51.43, 157.12 (CdO), 204.51 (CdO); MS (EI) m/z
F or m a tion of 7. To a solution of 1 (100 mg, 1.0 mmol) and
Pd(PPh3)4 (5.8 mg, 0.005 mmol) catalyst in anhydrous toluene
(10 mL) was added butylamine (79 mg, 1.1 mmol), and the
reaction mixture was stirred at room temperature for 24 h.
The solution was removed under reduced pressure, and the
residue was purified by silica gel column chromatography
(eluent: petroleum ether/ EtOAc )1/4) to give 7 as a viscous
228 (19.32) (M+), 185 (61.88) (M+ - 42), 156 (93.84) (M+
-
71), 86 (100) (M+ - 141); HRMS (EI) m/z 228.1800, C12H24N2O2
requires M, 228.1838.
F or m a tion of 13. This compound was obtained as a white
solid in the same manner as that described above using 1 (40
mg, 0.4 mmol) and dicyclohexylamine (80 mg, 0.44 mmol): mp
104-106 °C; 110 mg, 98%; IR (CHCl3) ν 1714 cm-1 (CdO); 1H
NMR (300 MHz, CDCl3, TMS) δ 0.95-1.53 (8H, m, CH2), 1.50-
1
oily product: 93 mg, 60%; IR (CHCl3) ν 1672 cm-1 (CdO); H
NMR (300 MHz, CDCl3, TMS) δ 0.94 (3H, t, J ) 7.3, CH3),

Transition-Metal-Catalyzed Reactions of Propargylamine
J . Org. Chem., Vol. 67, No. 1, 2002 21
2.0 (12H, m, CH2), 2.20 (3H, s, CH3), 3.38-3.52 (2H, m, CH2),
4.16 (2H, d, J ) 4.2 Hz, CH2), 5.16 (1H, s, NH); 13C NMR (75
MHz, CDCl3, TMS) δ 25.54, 26.46, 27.22, 31.64, 51.58, 55.15,
156.89 (CdO), 204.75 (CdO); MS (EI) m/z 280 (60.61) (M+),
223 (83.37) (M+ - 57), 138 (100) (M+ - 108); HRMS (EI) m/z
280.2147, C16H28N2O2 requires M, 280.2152.
F or m a tion of 19. This compound was prepared in the same
manner as that described above, but using 1,1-diethylpropar-
gylamine (1.01 g, 9.1 mmol), carbon disulfide (800 mg, 10.5
mmol) and Pd(OAc)2 (102 mg, 0.5 mmol) as a catalyst, to give
a white solid: 680 mg, 40%; mp 102-104 °C; IR (CHCl3) ν
1618, 1518, 1062 cm-1 1H NMR (CDCl3, TMS, 300 MHz) δ
;
F or m a tion of 14. This compound was obtained as a viscous
oily product in the same manner as that described above using
3 (62 mg, 0.4 mmol), cyclohexylamine (44 mg, 0.44 mmol), and
Pd(PPh3)4 (23 mg, 0.02 mmol): 2.0 mg, 2%; IR (CHCl3) ν 1788
1.02 (6H, t, J ) 7.4 Hz, CH3), 1.70-1.90 (4H, m, CH2), 5.05
(1H, d, J ) 2.6 Hz, CH), 5.23 (1H, d, J ) 2.6 Hz, CH), 7.96
(1H, s, NH); 13C NMR (CDCl3, TMS, 75 MHz) δ 7.81, 34.60,
79.18, 103.48, 148.27, 195.79 (CdS); MS (EI) m/z 187 (M+).
Anal. Calcd for C8H13NS2: C, 51.29, H, 6.99, N, 7.48. Found:
C, 51.37, H, 6.81, N, 7.46.
1
cm-1 (CdO); H NMR (300 MHz, CDCl3, TMS) δ 0.83 (6H, t,
J ) 7.4 Hz, CH3), 1.0-1.40 (6H, m, CH2), 1.50-1.75 (4H, m,
CH2), 1.76-1.90 (2H, m, CH3), 2.0-2.20 (2H, m, CH2), 3.60-
3.80 (1H, m, CH), 3.84 (1H, d, J ) 2.4 Hz, CH), 4.25 (1H, d, J
) 2.4 Hz, CH), 4.43 (1H, s, NH); MS (EI) m/z 236 (7.56) (M+),
207 (59.33) (M+ - 29), 125 (100) (M+ - 111); HRMS (EI) m/z
236.1909, C14H24N2O requires M, 236.1899.
F or m a tion of 15. This compound was obtained as a
colorless oil in the same manner as that described above using
3 (62 mg, 0.4 mmol) and diethylamine (32 mg, 0.44 mmol):
64 mg, 70%; IR (CHCl3) ν 1638 and 1707 cm-1 (CdO); 1H NMR
(300 MHz, CDCl3, TMS) δ 0.65 (6H, t, J ) 7.5 Hz, CH3), 1.14
(6H, t, J ) 7.5 Hz, CH3), 1.66 (1H, q, J ) 7.5 Hz, CH2), 1.68
(1H, q, J ) 7.5 Hz, CH2), 2.14 (3H, s, CH3), 2.53 (1H, q, J )
7.5 Hz, CH2), 2.56 (1H, q, J ) 7.5 Hz, CH2), 3.26 (4H, q, J )
7.5 Hz, CH2), 5.73 (1H, s, NH); 13C NMR (75 MHz, CDCl3,
TMS) δ 8.15, 13.91, 23.28, 27.69, 41.26, 69.79, 155.37 (CdO),
209.83 (CdO); MS (EI) m/z 229 (29.70) (MH+), 211 (27.6) (M+
- 18), 185 (38.7) (M+ - 43), 100 (100) (M+ - 128); HRMS (EI)
m/z 228.1829, C14H24N2O requires M, 228.1838.
F or m a tion of 16. This compound was obtained as a
colorless oil in the same manner as that described above using
3 (62 mg, 0.4 mmol) and diisopropylamine (44 mg, 0.44
mmol): 78 mg, 76%; IR (CHCl3) ν 1700 and 1785 cm-1 (CdO);
1H NMR (300 MHz, CDCl3, TMS) δ 0.67 (6H, t, J ) 7.5 Hz,
CH3), 1.24 (12H, d, J ) 7.0 Hz, CH3), 1.60-1.80 (2H, m, CH2),
2.15 (3H, s, CH3), 2.50-2.65 (2H, m, CH2), 4.03 (2H, quintet,
J ) 7.0 Hz, CH), 5.65 (1H, s, NH); 13C NMR (75 MHz, CDCl3,
TMS) δ 8.24, 13.91, 21.22, 27.78, 33.18, 44.16, 70.36, 155.09
(CdO), 210.04 (CdO); MS (EI) m/z 257 (23.3) (MH+), 213 (34.3)
(M+ - 44), 128 (64.2) (M+ - 128), 86 (100) (M+ - 179); HRMS
(EI) m/z 256.2146, C14H28N2O2 requires M, 256.2151.
F or m a tion of 17. This compound was obtained as a
colorless oil in the same manner as that described above using
3 (62 mg, 0.4 mmol) and dibutylamine (57 mg, 0.44 mmol):
89 mg, 78%; IR (CHCl3) ν 1638 and 1707 cm-1 (CdO); 1H NMR
(300 MHz, CDCl3, TMS) δ 0.67 (6H, t, J ) 7.5 Hz, CH3), 0.94
(6H, t, J ) 7.5 Hz, CH3), 1.25-1.50 (4H, m, CH2), 1.50-1.62
(4H, m, CH2), 1.60-1.80 (2H, m, CH2), 2.16 (3H, s, CH3), 2.50-
2.65 (2H, m, CH2), 3.20 (4H, t, J ) 7.5 Hz, CH2), 5.75 (1H, s,
NH); 13C NMR (75 MHz, CDCl3, TMS) δ 8.18, 13.91, 20.22,
23.28, 27.74, 30.82, 47.17, 69.87, 155.71 (CdO), 209.89 (Cd
O); MS (EI) m/z 285 (22.6) (MH+), 241 (48.9) (M+ - 44), 156
(100) (M+ - 128), 57 (58.1) (M+ - 227); HRMS (EI) m/z
282.2466, C16H32N2O2 requires M, 284.2464.
F or m a tion of 20. This compound was prepared in the same
manner as that described above, but using N-benzylpropar-
gylamine (1.32 g, 9.1 mmol), carbon disulfide (800 mg, 10.5
mmol), and Pd(OAc)2 (102 mg, 0.5 mmol) as a catalyst, to give
a colorless oil: 503 mg, 25%; IR (CHCl3) ν 1624, 1481, 1079
cm-1; 1H NMR (CDCl3, TMS, 300 MHz) δ 4.57 (2H, t, J ) 2.7
Hz, CH2), 5.02 (2H, s, CH2), 5.08 (1H, dd, J ) 4.9, 2.8 Hz, CH),
5.13 (1H, dd, J ) 4.9, 2.8 Hz, CH), 7.30-7.45 (5H, m, Ar); 13
C
NMR (CDCl3, TMS, 75 MHz) δ 51.91, 61.17, 104.82, 128.24,
128.34, 129.0, 134.54, 136.08, 194.45 (CdS); MS (EI) m/z 221
(M+); HRMS (EI) m/z 221.0326, C11H21NS2 requires M, 221.0333.
Gen er a l P r oced u r e for th e F or m a tion of Oxa zolid i-
n on es 1 a n d Im id a zolid in on es 2 u n d er High P r essu r e
of CO2. Propargylamine (550 mg, 10 mmol), Pd(PPh3)4 (45 mg,
0.05 mmol), PPh3 (13 mg, 0.05 mmol), and anhydrous toluene
20 mL and a magnetic stir bar were placed in the 50 mL glass
liner of a stainless steel autoclave under a nitrogen purge. The
autoclave was purged several times with CO2 (40 kg/cm2),
sealed, and stirred at room temperature for 24 h. After release
of the pressure, the solvent was removed under reduced
pressure, and the residue was purified by silica gel column
chromatograph (eluent: petroleum ether/EtOAc ) 1/4) to give
1 and 2 as a white solid.
Cr ysta l d a ta of 1: empirical formula, C4H5NO2; formula
weight, 99.09; crystal color, habit, colorless, column; crystal
dimensions, 0.28 × 0.30 × 0.25 mm; crystal system; mono-
clinic; lattice type, primitive; lattice parameters, a ) 10.776-
(2) Å, b ) 4.552(2) Å, c ) 10.073(2) Å, â ) 109.44ï, V ) 465.9(2)
Å3; space group P21/c(#14); Zvalue ) 4; Dcalcd ) 1.413 g/cm3; F000
) 208.00; µ(Mo KR) ) 1.15 cm-1; residuals: R; Rw ) 0.068;
0.138. Its structure has been deposited at the Cambridge
Crystallographic Data Centre and has been allocated the
deposition no. CCDC 164437.
Cr ysta l d a ta of 2: empirical formula, C7H8N2O; formula
weight, 136.15; crystal color, habit, colorless, prismatic; crystal
dimensions, 0.20 × 0.20 × 0.30 mm; crystal system; mono-
clinic; lattice type, primitive; lattice parameters, a ) 4.385(4)
Å, b ) 17.655(4) Å, c ) 9.622(3) Å, â ) 101.26(4)ï, V ) 730.6-
(8) Å3; space group P21/c(#14); Zvalue ) 4; Dcalcd ) 1.238 g/cm3;
F000 ) 288.00; µ(Mo KR) ) 0.86 cm-1; residuals: R; Rw ) 0.046;
0.053. Its structure has been deposited at the Cambridge
Crystallographic Data Centre and has been allocated the
deposition no. CCDC 164438.
F or m a tion of 18. To a solution of propargylamine (500 mg,
9.1 mmol) and carbon disulfide (800 mg, 10.5 mmol) in
anhydrous toluene (15 mL) was added a catalytic amount of
Pd(PPh3)4 (23.1 mg, 0.02 mmol) and triphenylphosphine (PPh3)
(5.24 mg, 0.02 mmol), and the reaction mixture was stirred at
room temperature for 24 h. The solution was concentrated
under reduced pressure, and the residue was purified by silica
gel column chromatography (eluent: petroleum ether/EtOAc)
1/4) to give 18 as a white solid: 1.2 g, 99%; mp 120-121 °C;
Ack n ow led gm en t. We thank the State Key Project
of Basic Research (Project 973) (No. G2000048007) and
the National Natural Science Foundation of China for
financial support (20025206). We also thank the Inoue
Photochirogenesis Project (ERATO, J ST) for chemical
reagents.
IR (CHCl3) ν 1626, 1490, 902 cm-1 1H NMR (CDCl3, TMS,
;
300 MHz) δ 4.67 (2H, t, J ) 2.7 Hz, CH2), 5.14 (1H, dd, J )
5.4, 2.7 Hz, CH2), 5.24 (1H, dd, J ) 4.8, 2.4 Hz, CH2), 7.96
(1H, s, NH); 13C NMR (CDCl3, TMS, 75 MHz) δ 57.05, 105.67,
141.13, 199.11 (CdS); MS (EI) m/z 131 (M+), HRMS (EI) m/z
131.9954, C4H6NS2 requires M, 131.9942.
Su p p or tin g In for m a tion Ava ila ble: 13C NMR spectra of
1-20; ORTEP diagrams of 1 and 2. This material is available
free of charge via the Internet at http://pubs.acs.org.
J O0014966