April 1998
SYNLETT
417
References and Notes
1.
Kant, J.; Walker, D. G. in The Organic Chemistry of β-Lactams,
Georg, G. I. ed.; VCH Publishers, Inc. New York 1992. Chapter 3.
2.
This chemistry has been carefully reviewed, see: Morin, R. B.;
Gorman, M., Eds. Chemistry and Biology of β-Lactam Antibiotics,
Academic Press, New York 1982-1983. Vol 1-3.
3.
For other, less general methods, to prepare N-vinyl-β-lactams,
see: (a) Hrytsak, M.; Durst, T. Heterocycles 1987, 26, 2393.
(b) Mastalerz, H.; Vinet, V. J. Chem. Commun. 1987, 1283.
(c) Just, G.; Liak, T.-J. Can. J. Chem. 1978, 56, 211. (d) Niu, Ch.;
Miller, M. J. Tetrahedron Lett. 1995, 36, 497. (e) Manhas, M. S.;
Van der Veen, J. M.; Wagle, D. R.; Hegde, V. R.; Bari, S. S.;
Kosarych, Z.; Ghosh, M.; Krishnan, L. Ind. J. Chem., Sect. B
1986, 25B, 1095. (f) Gunda, T. E.; Vieth, S.; Kover, K. E.;
Sztaricskai, F. Tetrahedron Lett. 1990, 31, 6707. (g) Fukuyama,
T.; Laird, A. A.; Schmidt, C. A. Tetrahedron Lett. 1984, 25, 4709.
(9) Cossio, F. P.; Palomo, C. Tetrahedron Lett. 1985, 26, 4235.
4.
(a) Georg, G. I.; He, P.; Kant, J.; Wu, Z.-J. J. Org. Chem. 1993,
58, 5771. (b) Georg, G. I.; Kant, J.; He, P.; Ly, A. M.; Lampe, L.
Tetrahedron Lett. 1988, 29, 2409. (c) Georg, G. I.; He, P.; Kant,
J.; Mudd, J. Tetrahedron Lett. 1990, 31, 451.
5.
6.
Dürckheimer, W.; Blumbach, J.; Latrell, R.; Sheunemann, K. H.
Angew. Chem., Int. Ed. Eng. 1985, 24, 180.
successively added. The mixture was washed with water and brine. The
organic layer was dried (MgSO ) and the solvent eliminated under
4
reduced pressure. The crude product was purified by column
chromatography (EtOAc/hexane 1/2)
To the best of our knowledge, the sole precedent in the use of a
seleno derivative to prepare a N-vinyl-2-azetidinone, is the
treatment of a β-lactam having a N-β-(phenylselenyl)ethyl moiety
General Method for the Synthesis of Compounds, 1a-e. Method A
with MCPBA/i-Pr NH to afford the exocyclic double bond. See,
Heck, J. V.; Christensen, B. G. Tetrahedron Lett. 1981, 22, 5027.
(Compounds 1a and 1e). BuLi (1.3 mmol, 1.6 M in hexanes) was added
2
o
dropwise via syringe to
a
cooled (-78 C) solution of
hexamethyldisilazane (1.35 mmol) in anhydrous THF (5 mL) under
7.
8.
Reviews: (a) Stammer, C. H. in Chemistry and Biochemistry of
Amino Acids, Peptides, and Proteins, Vol. 6, Weinstein, B., Ed.;
Marcel Dekker: New York, 1982. (b) Schmidt, U.; Hausler, J.;
Ohler, E.; Poisel, H. Progress in the Chemistry of Organic
Natural Products 1979, 37, 251.
argon. After 30 minutes, the resulting solution was transferred via
o
cannula to a cooled solution (-78 C) of the corresponding β-lactam (1
mmol) in anhydrous THF (5 mL) by using argon pressure. After stirring
o
o
1 h from -78 C to -60 C, PhSeBr (1.3 mmol) in THF (5 mL) was added
rapidly to the enolate solution, which causes an instantaneous
decolourization of the solution. After stirring for 1 h, the reaction
Racemization of imines derived from amino esters is a problem
found in the use of these compounds as substrates for the
Staüdinger reaction. For a recent example, see: Niu, C.; Petterson,
T.; Miller, M. J. J. Org. Chem. 1996, 61, 1014. In fact, when the
imine was prepared in boiling benzene total racemization was
observed. Conditions used through this work ensured that the
imine was obtained and used without racemization.
mixture was quenched with saturated aqueous NH Cl solution (7 mL)
4
and extracted with ethyl acetate (10 x 3 mL). The organic layer was
washed with saturated NaHCO solution (15 mL), brine (15 mL), and
3
dried (MgSO ). The solvent was removed under reduced pressure and
4
the obtained compound 3 was used in the next step without further
purification. Method B (Compounds 1b-d). This method was identical
to method A except for that the corresponding β-lactam was added
dropwise over the solution of LHMDS .
9.
Staüdinger, H. Liebigs Ann. Chem. 1907, 356, 51.
10. Arrieta, A.; Lecea, B.; Cossio, F. P.; Palomo, C. J. Org. Chem.
1988, 53, 3784, and references therein.
To a solution of the corresponding seleno-β-lactam 3 (1 mmol) in
11. (a) Cossio, F. P.; Arrieta, A.; Lecea, B.; Ugalde, J. M. J. Am.
Chem. Soc. 1994, 116, 2085. (b) Hegedus, L. S.; Montgomery, J.;
Narukawa, Y.; Snustad, D. C. J. Am. Chem. Soc. 1991, 113, 5784.
(c) Palomo, C.; Aizpurua, J. M.; Mielgo, A.; Linden, A. J. Org.
Chem. 1996, 61, 9186. Ojima, in a seminal series of papers, has
unambiguously established the configuration of 2-azetidinones
derived from chiral amino ester imines and Evans ketene
experimentally: (d) Ojima, I.; Chen, H.-J. C.; Qiu, X. Tetrahedron
1988, 44, 5307, and pertinent references therein. For 2-
azetidinones derived from D- and L-glyceraldehyde acetonide
imines, see: (e) Wagle, D. R.; Garai, C.; Chiang, J.; Monteleone,
M. G.; Kurys, B. E.; Strohmeyer, T. W.; Hedge, V. R.; Manhas,
M. S.; Bose, A. K. J. Org. Chem. 1988, 53, 4227.
o
CH Cl (5 mL), cooled to -78 C, was added dropwise a solution of m-
2
2
chloroperbenzoic acid (1.1 mmol, 55%) in
5 mL of CH Cl .
2 2
Immediately after the end of the addition, TLC analysis showed the
complete transformation of the starting material. The cold reaction
mixture was poured into a separatory funnel containing 30 mL of Et O
2
and 30 mL of 10% aqueous Na SO The organic layer was separated,
2
3.
washed twice with saturated aqueous NaHCO solution, dried (MgSO )
3
4
and concentrated under reduced pressure. The crude product was
purified by crystallization or flash chromatography.
Acknowledgment. Support for this work under Grant PB93-0442
(DGICYT - MEC, Spain) is acknowledged. C. P. thanks the UCM for
the receipt of a pre-doctoral grant.
12. Hwu, J. R.; Lai, L.-L.; Hakimelahi, G. H.; Davari, H. Helv. Chim.
Acta 1994, 77, 1037.
1
13.
H NMR analysis of the reaction mixtures showed a single
diastereoisomer in all cases.