N. ACHARJEE ET AL.
Data for(2,3-trans-3,3a-trans)-2-phenyl-3-oxophenyl-
pyrrolo-[1,2-b]-isoxazolidine (I/2psx)
Supporting information available
All NMR spectra of the isolated cycloadducts, X-ray data, theo-
retical data for atomic coordinates of reactants, orientation complexes,
products, and transition states along with IRC calculations and
theoretical H NMR results are available as supplementary data
files from the website of the journal/publisher and also from the
authors.
M.pt 114 8C (yield 34%).
—
IR: y ¼ 1669 (s,—C O), 763 (s), 698 (s), (Found: C, 77.60; H,
—
6.41; N, 4.71. C19H19NO2 requires C, 77.79; H, 6.53; N, 4.77).
1H NMR (CDCl3, d, 500 MHz): 4.07 (1H multiplet, H3a), 4.00 (1H
dd, J 8.3,5.0, H3), 5.34(1H d, J 8.3, H2), 2.12 (1H m, H4a), 1.97 (1H m,
H4b), 1.87 (1H m, H5a), 2.30 (1H m, H5b), 3.04 (1H ddd, J 13.5 Hz,
6.9 Hz, 9.8 Hz, H6b), 3.59 (1H ddd, J 13.5 Hz, 7.1 Hz, 3.0 Hz, H6a),
7.72 (2H dd, J 7.5 Hz,1.2 Hz, H2,6 (B)), 7.35 (2H t, J 7.5 Hz, H3,5(B)),
7.51 (1H tt, J 7.5 Hz,1.2 Hz, H4 (B)),7.24–7.32 (5H m, H2,3,4,5,6 (A))
[oxophenyl ring ¼ (B), phenyl ring (A),numbering refer to Fig. 1].
13C NMR (CDCl3, d, 125.5 MHz): 71.7 (C3a), 66.3 (C3), 83.7 (C2),
32.5 (C4), 24.8 (C5), 57.4 (C6), 137.1 (C1 (B)), 129.0 (C2,6 (B)), 129.0
1
Acknowledgements
One of the authors, Tapas Kumar Das, expresses thanks to the
University of Burdwan for extending computational support. The
other author, Nivedita Acharjee, expresses thanks to the Council
of Scientific and Industrial Research (C.S.I.R.) for financial support
and the University of Calcutta for laboratory infrastructure facility.
(C3,5 (B)), 133.8 (C4 (B)), 138.3 (C1 (A)), 126.9 (C2,6 (A)), 128.9 (C3,5
—
(A)), 128.8 (C4 (A)), 198.2 (C O) [oxophenyl ring ¼ (B), phenyl
—
ring (A), numbering refer to Fig. 1].
Data for (2,3-trans-3,3a-cis)-2-phenyl-
3-oxophenyl-pyrrolo-[1,2-b]-isoxazolidine (II/2psn)
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CONCLUSION
1,3-dipolar cycloadditions of 1-pyrroline-1-oxide to methyl
cinnamate and benzylidene acetophenone have been reported
and the results were rationalized through both experimental and
theoretical findings. The theoretical analyses of energy, enthalpy,
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presented to substantiate the experimentally found selectivities
in these cycloadditions. The reactions were 100% regioselective
leading to the exclusive generation of 3-carbomethoxy and
3-oxophenyl substituted isoxazolidines which were monitored
both experimentally as also through DFT calculations of the
appropriate transition states. However, the reaction involving E1
was endo-selective, whereas that of E2 was found to be
exo-selective due to modification in functional group from
carbomethoxy to keto-carbonyl in the dipolarophile moiety.
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Copyright ß 2010 John Wiley & Sons, Ltd.
J. Phys. Org. Chem. 2010, 23 1187–1195