COMMUNICATIONS
16: m.p. 81 ± 838C (hexane). 1H NMR (400 MHz, CDCl3): d 0.72 (s, 3H),
1.04 (s, 3H), 1.18 (s, 3H), 1.56 (s, 3H), 1.70 ± 1.90 (m, 3H), 2.04 ± 2.11 (m,
1H); 13C NMR (100.6 MHz, CDCl3): d 23.1, 28.5, 29.3, 30.9, 39.2, 41.7,
Solid-State Isomerization of
Atropodiastereomers: Effective
Diastereoselection through Polymorphic
Transformations**
1
44.2, 48.0, 90.0; IR (KBr): nÄ 1123 cm (S O); elemental analysis (%)
calcd for C9H16OS2: C 52.90, H 7.89; found: C 53.51, H 8.00.
Received: September 25, 2000
Revised: February 8, 2001 [Z15850]
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Cathy Einhorn, Andre Durif, Marie-Therese Averbuch,
and Jacques Einhorn*
Polymorphism is a fascinating phenomenon accompanied
by a lot of strange manifestations.[1] It is generally defined as
the existence of a given compound in more than one
crystalline form. In conformational polymorphs,[2] a given
molecular compound adopts different conformations in
different polymorphs. But, at a molecular level, conforma-
tional changes may involve quite high energy barriers,
allowing in some cases the isolation of separate stereoisomers
(atropisomers) which do not interconvert rapidly in solution
at room temperature, but do so if enough energy is supplied.
Herein we report solid-state thermal isomerizations of com-
pounds 1, which present such a type of atropisomerism. These
isomerizations have features reminiscent of polymorphic
transformations, although not involving polymorphs in the
usual sense of the word.[3]
[1] A. Ishii, M. Nakabayashi, J. Nakayama, J. Am. Chem. Soc. 1999, 121,
7959 ± 7960.
[2] R. M. Dodson, V. Srinivasan, K. S. Sharma, R. F. Sauers, J. Org. Chem.
1972, 37, 2367 ± 2372.
[3] Review: A. R. V. Murthy, T. R. N. Kutty, D. K. Sharma, Int. J. Sulfur
Chem. B 1971, 6, 161 ± 175.
[4] a) R. Steudel, M. Rebsch, Angew. Chem. 1972, 84, 344 ± 345; Angew.
Chem. Int. Ed. Engl. 1972, 11, 302 ± 303; b) R. Steudel, J. Latte, Angew.
Chem. 1974, 86, 648; Angew. Chem. Int. Ed. Engl. 1974, 13, 603 ± 604;
c) R. Steudel, P. Luger, H. Bradaczek, M. Rebsch, Angew. Chem.
1973, 85, 452 ± 453; Angew. Chem. Int. Ed. Engl. 1973, 12, 423 ± 424;
d) R. Steudel, T. Sandow, Angew. Chem. 1978, 90, 644 ± 645; Angew.
Chem. Int. Ed. Engl. 1978, 17, 611 ± 612.
[5] R. Steudel, T. Sandow, Angew. Chem. 1976, 88, 854 ± 855; Angew.
Chem. Int. Ed. Engl. 1976, 15, 772 ± 773; R. Steudel, R. Reinhardt, T.
Sandow, Angew. Chem. 1977, 89, 757 ± 758; Angew. Chem. Int. Ed.
Engl. 1977, 16, 716.
As depicted in Scheme 1, the synthesis of 1 has been
achieved by Diels ± Alder reactions between isobenzofuran 2
and maleimide or N-benzylmaleimide, giving adducts 3a or
3b in good yields. Their aromatization under strongly acidic
conditions furnished 1a and 1b quantitatively. Demethylation
of 1a and 1b gave diphenols 1c and 1d in high yields.
[6] R. Steudel, J. Steidel, Angew. Chem. 1978, 90, 134 ± 135; Angew.
Chem. Int. Ed. Engl. 1978, 17, 134 ± 135.
[7] A referee proposed that we examine the reaction of S8O with trapping
reagents, with regard to the mechanism of the reactions reported here.
The reaction of S8O, prepared by a reported method,[4b] with 2,3-
dimethyl-1,3-butadiene in dichloromethane at room temperature for
1 h gave 2 in only 1.4% yield, while that carried out under reflux gave
2 in 25% yield. At present we do not have direct evidence for the
existence of free S2O in solution, so that ªS2Oº should be read as ªS2O
equivalentº throughout this paper.
[8] For a review, see: G. Opitz, Angew. Chem. 1967, 79, 161 ± 177; Angew.
Chem. Int. Ed. Engl. 1967, 6, 107 ± 123.
[9] B. F. Bonini, G. Maccagnani, G. Mazzanti, J. Chem. Soc. Chem.
Commun. 1976, 431.
[10] B. F. Bonini, A. Cappelli, G. Maccagnani, G. Mazzanti, Gazz. Chim.
Ital. 1975, 105, 827 ± 839; B. F. Bonini, G. Maccagnani, Tetrahedron
Lett. 1973, 3585 ± 3588; B. F. Bonini, G. Maccagnani, A. Wagenaar, L.
Thijs, B. Zwanenburg, J. Chem. Soc. Perkin Trans. 1 1972, 2490 ± 2493;
L. Thijs, A. Wagenaar, E. M. M. van Rens, B. Zwanenburg, Tetrahe-
dron Lett. 1973, 3589 ± 3592; C. G. Venier, C. G. Gibbs, Tetrahedron
Lett. 1972, 2293 ± 2296.
[11] W. Adam, J. Bialas, L. Hadjiarapoglou, Chem. Ber. 1991, 124, 2377; W.
Adam, L. Hadjiarapoglou, A. Smerz, Chem. Ber. 1991, 124, 227 ± 232.
[12] The trans stereochemistry of 9 and 10 was determined by X-ray
crystallography and will be reported elsewhere.
[13] S.-Y. Tang, C. W. Brown, Inorg. Chem. 1975, 14, 2856 ± 2858; A. G.
Hopkins, S.-Y. Tang, C. W. Brown, J. Am. Chem. Soc. 1973, 95, 3486 ±
3490.
Scheme 1. Reagents, conditions, and yields: a) for 3a: 1 equiv maleimide,
toluene, RT, 6 h, 96%; for 3b: 1 equiv N-benzylmaleimide, toluene, RT,
6 h, 81%; b) 6 equiv MeSO3H, CH2Cl2, RT, 12 h, >99% for 1a, >99% for
1b; c) 3 equiv BBr3, CH2Cl2, 788C to RT, 15 h, 98% for 1c, 99% for 1d.
Full details can be found in the Supporting Information. RT room
temperature.
[14] D. H. R. Barton, F. S. Guziec, Jr., I. Shahak, J. Chem. Soc. Perkin
Trans. 1 1974, 1794 ± 1799, and references therein.
[*] Dr. J. Einhorn, Dr. C. Einhorn, Dr. A. Durif, Dr. M.-T. Averbuch
[15] R. Ahmed, W. Lwowsi, Tetrahedron Lett. 1969, 3611 ± 3612.
[16] M. Sander, Chem. Rev. 1966, 66, 297 ± 339; N. Latif, I. Fathy, N.
Mishriky, B. Haggag, Can. J. Chem. 1966, 44, 629 ± 632.
[17] F. S. Guziec, Jr., C. J. Murphy, E. R. Cullen, J. Chem. Soc. Perkin
Trans. 1 1985, 107 ± 113.
Â
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Laboratoire dꢁEtudes Dynamiques et Structurales de la Selectivite
UMR 5616
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Universite Joseph Fourier
BP 53, 38041 Grenoble Cedex 9 (France)
Fax : (33)4-76-51-48-36
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[18] L. v. Vargha, E. Kovacs, Chem. Ber. 1942, 75, 794 ± 802; N. Tokura, T.
Nagai, S. Matsumura, J. Org. Chem. 1966, 31, 349 ± 350.
[19] Y.-N. Jin, A. Ishii, Y. Sugihara, J. Nakayama, Tetrahedron Lett. 1998,
39, 3525 ± 3528.
[20] K. A. Muszkat, E. Fischer, J. Chem. Soc. B 1967, 662 ± 678.
[21] H. Nozaki, R. Noyori, K. Sisido, Tetrahedron 1964, 20, 1125 ± 1132.
[22] J. Nakayama, A. Ishii, Adv. Heterocycl. Chem. 2000, 77, 221 ± 284.
[23] A. Ishii, Y. Jin, Y. Sugihara, J. Nakayama, J. Chem. Soc. Chem.
Commun. 1996, 2681 ± 2682.
[**] Prof. Jean-Louis Pierre and Prof. Jacques Reisse are gratefully
acknowledged for fruitful discussions, as well as Dr. Christian Philouze
for assistance with the X-ray crystallographic studies. We would also
like to thank one of the referees for valuable suggestions. We thank
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Universite Joseph Fourier and CNRS for financial support.
Supporting information for this article is available on the WWW under
1926
ꢀ WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001
1433-7851/01/4010-1926 $ 17.50+.50/0
Angew. Chem. Int. Ed. 2001, 40, No. 10