4510
G. E. Daia et al. / Tetrahedron Letters 43 (2002) 4507–4510
8. Thermal cycloaddition of furan and 2,5-dimethylfuran
References
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1. Ghosh, C. K.; Bhattacharyya, K.; Ghosh, C. Tetrahedron
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with PhSO2CꢀCH (CH2Cl2, rt, 3–41 days) provides the
pincer anti exo–endo and exo–exo adducts, Arjona, O.;
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the choice from six diastereomeric adducts to two i.e. 8,
or the anti endo–endo isomer. The latter is excluded on
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observed in furan cycloadditions.4 exo–exo Stereochem-
istry is normally observed under thermodynamic condi-
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5. Daia, G. E.; Gabbutt, C. D.; Hepworth, J. D.; Heron, B.
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6. New compounds were characterised by 1H and 13C
NMR, HRMS and elemental analysis.
7. syn Refers to the disposition of the bridgehead methyl
groups. lH(CDCl3) 1.82 (3H, s, Me), 1.85 (3H, s, Me),
3.62 (3H, s, CO2Me), 3.80 (1H, d, J14a,15=5.1, 14a-H),
5.09 (1H, s, 14-H), 5.61 (1H, d, J15,14a=5.1, 15-H), 7.55
(6H, m, Ar-H), 8.21–8.28 (2H, m, 1-H, 12-H). Crystal
data for 6: C28H20O8, M=484.44, triclinic, space group
(
,
P1, a=7.5200(5), b=13.984(4), c=21.53(2) A, h=
3
,
102.710(3), i=93.440(8), k=94.76(2)°, U=2194(2) A ,
Dc=1.467 mg m−3, Z=4, Mo–Ka radiation (u=0.71069
A), v=0.108 mm−1, T=150(2) K, 5958 measured reflec-
,
tions, 5044 observed reflections (Rint=0.0722), R1=
0.0386 [I>2|(I)], wR2=0.0643 (all data). Crystallographic
data (excluding structure factors) for the structure in this
paper has been deposited with the Cambridge Crystallo-
graphic Data Centre as supplementary publication num-
ber CCDC 157078.
13. Oleinik, A. F.; Adamskaya, E. V.; Novitskii, K. Y. Chem.
Heterocyclic Compd., Engl. Transl. 1982, 453.
14. Huke, J. P.; Hillier, I. H.; Infield, R. M.; Suschitzky, J. L.
J. Chem. Soc., Perkin Trans. 2 1984, 2119.
15. Maggiani, A.; Tubul, A.; Brun, P. Chem. Commun. 1999,
2495.