6512
L. Marzorati et al. / Tetrahedron Letters 48 (2007) 6509–6513
Ts
N
OH
OH
K CO / TsCl
2
3
t
-BuNH2
TsHN
TsHN
CH Cl2
2
DCC, HOBT (cat)
CONHt-Bu
CO H
2
CONHt-Bu
catalyst
5
6
Scheme 6. PTC preparation of 5.
Table 3. Catalyst efficiency screening for the preparation of 5
Sweeney, J. Tetrahedron: Asymmetry 1997, 8, 1693; (i)
Li, A.-H.; Dai, L.-X. Chem. Rev. 1997, 97, 2341; (j)
Mitchinson, A.; Nadin, A. J. Chem. Soc., Perkin Trans. 1
2000, 2862; (k) Cardillo, G.; Gentilucci, L.; Tolomelli, A.
Aldrichim. Acta 2003, 36, 39; (l) Bisol, T. B.; S a´ , M. M.
Quim. Nova 2007, 30, 106.
a,b
Yield (%)
Entry
Catalyst
33Me
Aliquat 336
Bu NHSO
q
1
2
3
4
5
C
16
H
3
NBr
3.06
1.38
1.00
—
98
99
57
54
0
4
4
18-Crown-6
None
3. Sudo, A.; Morioka, Y.; Sanda, F.; Endo, T. Tetrahedron
Lett. 2004, 45, 1363.
a
4. Tanner, D.; Harden, A.; Johansson, F.; Wyatt, P.;
Andersson, P. G. Acta Chem. Scand. 1996, 50, 361.
5. Baldwin, J. E.; Spivey, A. C.; Schofield, C. J.; Sweeney, J.
B. Tetrahedron 1993, 49, 6309.
4
2 3
equiv of K CO , 1.0 equiv of TsCl, catalyst (10 mol %), dibenzyl
ether as internal standard.
After 5.5 h.
b
6
. (a) Li, Z.; Conser, K. R.; Jacobsen, E. N. J. Am. Chem.
Soc. 1993, 115, 5326; (b) Evans, D. A.; Faul, M. M.;
Bilodeau, M. T.; Anderson, B. A.; Barnes, D. M. J. Am.
Chem. Soc. 1993, 115, 5328; (c) Evans, D. A.; Faul, M. M.;
Bilodeau, M. T. J. Am. Chem. Soc. 1994, 116, 2742; (d) Li,
Z.; Quan, R. W.; Jacobsen, E. N. J. Am. Chem. Soc. 1995,
117, 5889; (e) Gillespie, K. M.; Sanders, C. J.; O’Shaugh-
nessy, P.; Westmoreland, I.; Thickitt, C. P.; Scott, P. J.
Org. Chem. 2002, 67, 3450; (f) Jain, S. L.; Sain, B.
Tetrahedron Lett. 2003, 44, 575; (g) Chanda, B. M.; Vyas,
R.; Landge, S. S. J. Mol. Catal. A: Chem. 2004, 223, 57.
. (a) Chen, D.; Kim, S. H.; Hodges, B.; Li, G. Arkivoc 2003,
tert-Butyl N-tosyl-L-serine amide 6, to be used as a pre-
1
4
15
cursor of 5, was prepared from N-tosyl-L-serine and
tert-butylamine. As for the cyclization of 6, the efficien-
cies of four catalysts were evaluated by comparison of
1
crude yields determined by H NMR (Table 3).
As can be seen, more accessible catalysts13 (Table 3,
entries 1 and 2) are more efficient as compared to the
lipophilic Bu NHSO (Table 3, entry 3), suggesting that
4
4
7
the rate of transfer of the anionic intermediates plays a
major role in the overall kinetics. In a preparative
experiment, 18-Crown-6 was employed on the basis of
a compromise between yield (60%) and easy of purifica-
5
6; (b) Chen, D.; Timmons, C.; Guo, L.; Xu, X.; Li, G.
Synthesis 2004, 2479.
. Davis, F. A.; Reddy, G. V.; Liang, C.-H. Tetrahedron
Lett. 1997, 38, 5139.
. (a) Tanner, D.; Birgersson, C.; Dhaliwal, H. K. Tetra-
hedron Lett. 1990, 31, 1903; (b) Fujii, N.; Nakai, K.;
Habashita, H.; Hotta, Y.; Tamamura, H.; Otaka, A.;
Ibuka, T. Chem. Pharm. Bull. 1994, 42, 2241; (c) Solomon,
M. E.; Lynch, C. L.; Rich, D. H. Synth. Commun. 1996,
8
1
6
tion of the desired enanatiomerically pure aziridine 5.
9
In summary, we have developed a facile PTC protocol17
for the preparation of some synthetically valuable enan-
tiomerically pure N-tosyl aziridine-2-carboxylates 1 and
2
6, 2723.
2
, starting from readily available b-hydroxy-a-amino-
1
0. (a) Nakagawa, Y.; Tsuno, T.; Nakagima, K.; Iwai, M.;
esters. Moreover, the new aziridine carboxamide 5 could
be also prepared by the same methodology.
Kawai, H.; Okawa, K. Bull. Chem. Soc. Jpn. 1972, 45,
1
162; (b) Imae, K.; Kamachi, H.; Yamashita, H.; Okita,
T.; Okuyama, S.; Tsuno, T.; Yamasaki, T.; Sauada, Y.;
Ohbayashi, M.; Naito, T.; Oki, T. J. Antibiot. 1991, 44, 76.
Acknowledgment
11. Liotta, C. L.; Burgess, E. M.; Ray, C. C.; Black, E. D.;
Fair, B. E. In Mechanism of Phase-Transfer Catalysis: the
Omega Phase; ACS Symposium Series 326; American
Chemical Society: Washington, DC, 1987; p 15.
This work was made possible by grants from FAPESP
and CNPq.
1
2. (a) Starks, C. M.; Liotta, C. L.; Halpern, M. Phase-
Transfer Catalysis Fundamentals, Application, and Indus-
trial Perspectives; Chapman & Hall: New York, 1994;
Chapter 6, p 277; (b) Starks, C. M.; Liotta, C. L.; Halpern,
M. Phase-Transfer Catalysis Fundamentals, Application,
and Industrial Perspectives; Chapman & Hall: New York,
1994, p 275; (c) Starks, C. M.; Liotta, C. L.; Halpern, M.
Phase-Transfer Catalysis Fundamentals, Application, and
Industrial Perspectives; Chapman & Hall: New York,
1994; Chapter 4, p 128.
References and notes
1
. Sweeney, J. B. Chem. Soc. Rev. 2002, 31, 247, and
references cited therein.
. (a) Tanner, D. Angew. Chem., Int. Ed. Engl. 1994, 33, 599;
b) Atkinson, R. S. Tetrahedron 1999, 55, 1519; (c)
Zwanenburg, B.; ten Holt, P. Top. Curr. Chem. 2001,
2
(
2
3
16, 93; (d) Lee, W. K.; Ha, H.-J. Aldrichim. Acta 2003,
6, 57; (e) Beresford, K. J. M.; Church, N. J.; Young, D.
13. Halpern, M.; Sasson, Y.; Rabinovitz, M. Tetrahedron
1982, 38, 3183.
W. Org. Biomol. Chem. 2006, 4, 2888; (f) McCoull, W.;
Davis, F. A. Synthesis 2000, 1347; (g) Hu, X. E.
Tetrahedron 2004, 60, 2701; (h) Osborn, H. M. I.;
14. Amidation was performed using 1 equiv of DCC and
10 mol % of 1-hydroxybenzotriazole as coupling reagents,
in THF yielding 82% of 6, as a solid, still containing traces