7
124
M. Periasamy et al. / Tetrahedron Letters 42 (2001) 7123–7125
11
Table 1. Reaction of diimines with the TiCl /Zn reagent system
4
Yield (%)d
[h] (c, solvent)
25
Entry
1
R
2
D
a,b
−77.4 (0.93, CHCl3)b
−136 (1, CHCl3)
1
2
3
4
5
6
1a
1b
1c
1d
1e
1f
C H
p-ClC H
p-CH C H
o-OCH C H
2a
2b
2c
2d
2e
75
73
79
86
85
30
6
5
c
6
4
c
−104 (1, CHCl )
3
6
4
3
b,e
a,b
+8 (1, CHCl3)
3
6
4
c
1-Naphthyl
C H
+200 (1, CHCl3)
+15.4 (0.26, CHCl3)
c
2f
4
9
a
The products 2a and 2d were identified by the spectral data (IR, 1H NMR, 13C NMR and MS) and comparison with reported data.7
b
c
7
Lit [h]D −70 (c 1.7, CHCl ) and +6.1 (c 3.3, CHCl ) for 2a and 2d, respectively.
3
3
The products 2b, 2c, 2e and 2f were identified using the spectral data (IR, H NMR, 13C NMR and MS11).
1
d
e
Yields of isolated products.
[
h]D −17 (c 1, MeOH).
comparison of the [h] values suggests that the configu-
ration of the new chiral centers in these cases may be also
2. Shimizu, M.; Iida, T.; Fujisawa, T. Chem. Lett. 1995,
609–610.
D
(
3S,4S) as in 2a. However, on the basis of the [h] values
3. Smith, J. G.; Ho, I. J. Org. Chem. 1972, 37, 653–656.
4. Mangenuy, P.; Tejero, T.; Alexakis, A.; Grosjean, F.;
Normant, J. Synthesis 1988, 255–257.
D
of the products 2d and 2e obtained from the diimines 1d
and 1e the configurations of the new chiral centers at C3
and C4 cannot be assigned without ambiguity.
5. Hatano, B.; Ojawa, A.; Hirao, T. J. Org. Chem. 1998, 63,
9421–9424.
7
Shono et al. previously reported the synthesis of com-
6. Betshart, V. C.; Schmidt, B.; Seebach, D. Helv. Chim.
Acta 1988, 71, 1999–2021.
7. Shono, T.; Kise, N.; Shirakawa, E.; Matsumoto, H.;
pounds 2a and 2d through an electroreduction method.
They assigned trans stereochemistry of the phenyl groups
in compound 2a on the basis of NOE enhancements
observed in H NMR (400 MHz) spectrum. Further,
these authors suggested trans stereochemistry for 2d and
several other derivatives by comparison of H NMR (200
MHz) data. It seems reasonable to assign trans stere-
oconfigurations for the aryl and t-butyl derivatives
reported here as they exhibit H NMR (200 MHz) signals
similar to that reported for 2a and 2d and other similar
derivatives. However, these trans stereochemical assign-
Okazaki, E. J. Org. Chem. 1991, 56, 3063–3067.
1
8. Periasamy, M.; Reddy, M. R.; Kanth, J. V. B. Tetra-
hedron Lett. 1996, 37, 4767–4770.
1
9. Periasamy, M.; Srinivas, G.; Karunakar, G. V.; Bharathi,
P. Tetrahedron Lett. 1999, 40, 7577–7580.
10. The X-ray diffraction measurements were carried out at
1
293 K on an automated Enraf–Nonious MACH 3 dif-
fractometer using graphite-monochromated, Mo-K (u=
a
7
0.71073 A
-scan mode. The data were reduced using the XTAL
,
) radiation. Intensity data were collected by the
ꢀ
ments are only tentative.
program. No absorption correction was applied. Crystal
structure data for compound 2a: q range for data collec-
In conclusion, we anticipate that the simple method of
synthesis of chiral 3,4-disubstituted 2,5-diazabicy-
clo[4.4.0]decanes reported here using low-valent titanium
species would stimulate further research in the synthetic
applications of these chiral derivatives as a 3,4-diaryl-2,5-
diazabicyclo[4.4.0]decane derivative has shown excellent
chiral discriminating ability (80–99%) in diethylzinc
20 24
tion is 1.64–24.97°. Empirical formula C H N2
0
.25H O, colorless needles (0.38×0.52×0.8 mm), crystal
2
system is monoclinic, space group C , unit cell dimen-
2
sions: a=25.307(2), b=5.4788(10), c=15.9953(14) A
,
, h=
3
9
D
0, i=129.11(2), k=90°; volume 1721.0(4) A
,
, Z=4,
3
=1.360 Mg/m , absorption coefficient is 0.084
mm , F(000)=744, index ranges −305h530, −65k50,
185l518, total reflections collected were 3368/1686
calcd
−
1
7
addition to certain aldehydes.
−
reflections with Rint=0.0436. The structure was solved by
direct methods and refined by full-matrix least-squares
procedure using the SHELX-97 program package. The
refinement was carried out using 931 observed [F>4|(F)]
reflections and converged to a final R =0.0484, wR =
Acknowledgements
1
2
We are thankful to the UGC, New Delhi for support
under the Special Assistance Program. G.S. and S.S.
thank UGC, New Delhi for financial support. X-Ray
data were collected using the National Single Crystal
X-ray facility, School of Chemistry, University of Hyder-
abad, funded by DST, New Delhi. We thank Dr. S. Pal
for helpful discussion.
0
.1369 and goodness of fit is 0.813 with largest difference
−
3
peak and hole 0.197 and −0.230 e A , respectively. The
configuration of the compound 2a moiety present in the
crystal structure was confirmed to be (3S,4S) by using the
platon 98 program, A. L. Spak, version 291198.
,
11. General experimental procedure: In dry THF (100 ml),
TiCl (20 mmol) was added under an N atmosphere at
4
2
0°C. Zn (40 mmol) was added with a solid addition flask
for 10 min. The reaction mixture was stirred for 0.5 h at
0°C and the imine (5 mmol) in 50 ml of THF was added
for 15 min. The reaction mixture was stirred for 0.5 h at
0°C and for 12 h at 25°C. It was quenched with saturated
References
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2