2
026
R. L. Paddock et al. / Tetrahedron Letters 45 (2004) 2023–2026
steel Parr high pressure reactor was charged with
References and notes
III
ꢀ5
Co TPP(Cl)(20.0 mg, 2.76 · 10 mol), propylene oxide
ꢀ
2
(
5 mL, 4.15 g, 7.14 · 10 mol), DMAP (6.7 mg,
1
2
3
. Behr, A. Carbon Dioxide Activation by Metal Complexes;
VCH: New York, 1988.
. Darensbourg, D. J.; Holtcamp, M. W. Coord. Chem. Rev.
ꢀ5
5
was placed under a constant pressure of CO
.51 · 10 mol), and CH
2
Cl
2
(1.0 mL). The reaction vessel
for 5 min to
2
allow the system to equilibrate and then heated to 120 ꢀC
for the allotted time. The vessel was then cooled to
ambient temperature by placement in a dry ice/water bath.
The pressure was then released and the contents trans-
ferred to a 50 mL round-bottom flask. Unreacted sub-
strate and solvent were removed in vacuo and the product
was then isolated via Kugelrohr distillation (65 ꢀC/
1
996, 153, 155–174.
. Biggadike, K.; Angell, R. M.; Burgess, C. M.; Farrell, R.
M.; Hancock, A. P.; Harker, A. J.; Irving, W. R.;
Ioannou, C.; Procopiou, P. A.; Shaw, R. E.; Solanke, Y.
E.; Singh, O. M. P.; Snowden, M. A.; Stubbs, R. J.;
Walton, S.; Weston, H. E. J. Med. Chem. 2000, 43, 19–21.
. Shaikh, A.-A. G.; Sivaram, S. Chem. Rev. 1996, 96, 951–
4
5
0
.2 mmHg). Analysis of the product was carried out via
976.
GC–MS, GC (using an instrument equipped with FID
detector and a 30 m HP-5 capillary column with 0.32 mm
inner diameter and 0.25 mm film thickness. Temperature
program: initial time ¼ 0, initial temperature ¼ 50 ꢀC,
rate ¼ 15 ꢀC/min; final time ¼ 10 min, final tempera-
ture ¼ 250 ꢀC), and NMR.
. Arakawa, H.; Aresta, M.; Armor, J. N.; Barteau, M. A.;
Beckman, E. J.; Bell, A. T.; Bercaw, J. E.; Creutz, C.;
Dinjus, E.; Dixon, D. A.; Domen, K.; DuBois, D. L.;
Eckert, J.; Fujita, E.; Gibson, D. H.; Goddard, W. A.;
Goodman, D. W.; Keller, J.; Kubas, G. J.; Kung, H. H.;
Lyons, J. E.; Manzer, L. E.; Marks, T. J.; Morokuma, K.;
Nicholas, K. M.; Periana, R.; Que, L.; Rostrup-Nielson,
J.; Sachtler, W. M. H.; Schmidt, L. D.; Sen, A.; Somorjai,
G. A.; Stair, P. C.; Stults, B. R.; Tumas, W. Chem. Rev.
2
2
2. No reaction was observed in the absence of Lewis base.
3. Aida, T.; Inoue, S. J. Am. Chem. Soc. 1983, 105, 1304–
1
309.
4. Increasing the Cl-concentration by the addition of excess
NBu Cl does not lead to a significant increase in TOF,
2
2
001, 101, 953–996.
. Baba, A.; Nozaki, T.; Matsuda, H. Bull. Chem. Soc. Jpn.
987, 60, 1552–1554.
. B €a ckvall, J. E.; Karlsson, O.; Ljunggren, S. O. Tetrahe-
dron Lett. 1980, 21, 4985–4988.
. Calo, V.; Nacci, A.; Monopoli, A.; Fanizzi, A. Org. Lett.
6
7
8
9
4
suggesting that the more Lewis basic DMAP is primarily
responsible for the ring-opening of the Co-activated epoxide.
5. That the ring opening of the epoxide occurs at the least
substituted position, as consistent with a nucleophilic ring-
opening mechanism, should not change the stereochemis-
try at the more substituted carbon of the epoxide. This is
indeed the case: the reaction of chirally pure (S)-(+)pro-
pylene oxide results in pure (S)-(+) propylene carbonate.
6. Darensbourg, D. J.; Yarbrough, J. C. J. Am. Chem. Soc.
1
2
2
002, 4, 2561–2563.
. Fujinami, T.; Suzuki, T.; Kamiya, M.; Fukuzawa, S.;
Sakai, S. Chem. Lett. 1985, 199–200.
1
1
1
0. Kihara, N.; Hara, N.; Endo, T. J. Org. Chem. 1993, 58,
198–6202.
1. Kruper, W. J.; Dellar, D. D. J. Org. Chem. 1995, 60, 725–
27.
2. Nomura, R.; Ninagawa, A.; Matsuda, H. J. Org. Chem.
980, 45, 3735–3738.
3. Peppel, W. J. Ind. Eng. Chem. 1958, 50, 767–770.
4. Yamaguchi, K.; Ebitani, K.; Yoshida, T.; Yoshida, H.;
Kaneda, K. J. Am. Chem. Soc. 1999, 121, 4526–4527.
5. Yang, H.; Gu, Y.; Deng, Y.; Shi, F. Chem. Commun. 2002,
2
2
6
2
002, 124, 6335–6342.
7. Although the DMAP–CO
terized, the analogous DBU–CO
and characterized, see: Franco et al. Tetrahedron Lett.
002, 43, 4091–4093.
adduct has not been charac-
adduct has been isolated
7
2
2
1
2
1
1
2
2
3
3
8. Cyclohexene oxide was employed as substrate and found
to yield only the corresponding polycarbonate.
9. Katzhend, J.; Sarel, S.; Ringel, I. J. Chem. Soc., Perkin
Trans. 2 1972, 14, 2019–2025.
0. Lorincz, T.; Erden, I. Synth. Commun. 1986, 16, 123–
1
1
274–275.
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H.; Yoshihara, M.; Maeshima, T. Chem. Commun. 1997,
1
30.
1
1. 4-Butyl-1,3-dioxolan-2-one: H NMR (CD
2
Cl
), 1.69 (m, 1H, CH
O), 4.50 (t, 1H, CH
Cl ): d 14.12, 22.81, 27.00,
2
): d 0.92 (t,
), 1.78 (m,
O), 4.70
1
129–1130.
7. Iwasaki, T.; Kihara, N.; Endo, T. Bull. Chem. Soc. Jpn.
000, 73, 713–719.
8. Paddock, R. L.; Nguyen, S. T. J. Am. Chem. Soc. 2001,
23, 11498–11499.
9. Shen et al. have reported that Co salen also catalyzed the
formation of propylene carbonate in the presence of Lewis
bases, see: Shen, Y.-M.; Duan, W.-L.; Shi, M. J. Org.
Chem. 2003, 68, 1559–1562.
0. The Co TPP(Cl) complex was synthesized according to a
known literature procedure, see: Tse et al. Organometallics
998, 17, 2651–2655.
1. Representative procedure for the coupling reaction of
epoxides and CO : On the bench top, a 125 mL stainless
3
1
H, CH
H, CH
3
), 1.37 (m, 4H, CH
), 4.05 (t, 1H, CH
2
2
1
1
1
2
2
2
2
1
3
(
m, 1H, CHO). C NMR (CD
2
2
3
C
1
2
4.00, 70.02, 77.70, 155.55. HRCIMS: m=z Calcd for
1
þ
II
7
H
13
O
,3-dioxolan-2-one: H NMR (CD
3
([MH] ): 145.0859. Found: 145.0858. 4-Benzyl-
1
2
Cl
B
2
): d 2.97–3.13 (dd,
of ABX system,
H, benzylic protons,
A
and
J
4
AB ¼ 14:5 Hz, JAX ¼ JBX ¼ 7 Hz), 4.15 (t, 1H, CH
.44 (t, 1H, CH O), 4.92 (m, 1H, CHO), 7.23 (m, 2H,
aromatic-H), 7.29 (m, 1H, aromatic-H), 7.34 (m, 2H,
2
O),
III
2
2
1
3
aromatic-H). C NMR (CD
1
2
2
Cl ): d 40.07, 69.16, 77.50,
1
27.93, 129.39, 129.90, 134.94, 155.22. HREIMS: m=z
2
þ
10 3
H O ([M] ): 178.0624. Found: 178.0623.
Calcd for C10
2