Diels-Alder reaction of thiophene: Dramatic effects of high-pressure/ solvent-free conditions

Angewandte Chemie - International Edition

Volumn 43, Issue 15, 2004, Pages 2015-2017

  Kumamoto, Koji ^a   Fukada, Isao ^b   Kotsuki, Hiyoshizo ^a  

^a KOCHI UNIVERSITY   (Japan)

^b MITSUI CHEMICALS INC   (Japan)

Author keywords

Cycloaddition; High pressure chemistry; Solvent effects; Thiophene

Indexed keywords

ACRYLICS; HIGH PRESSURE EFFECTS; SOLVENTS;

ACRYLIC DIENOPHILES; DIEL-ALDER REACTION;

CHEMICAL REACTIONS;

DICHLOROMETHANE; HEXANE; MALEIMIDE DERIVATIVE; SOLVENT; THIOPHENE;

ARTICLE; CHEMICAL REACTION KINETICS; DIELS ALDER REACTION; ISOMER; POLYMERIZATION; PRESSURE GRADIENT; PROTON NUCLEAR MAGNETIC RESONANCE; SOLID STATE; TEMPERATURE DEPENDENCE;

EID: 4544349123     PISSN: 14337851     EISSN: None     Source Type: Journal    
DOI: 10.1002/anie.200353487     Document Type: Article

References (15)

1. O. Diels, Ber. Dtsch. Chem. Ges. A 1936, 69, 195.
2. Thiophene and Its Derivatives, Part 1 (Ed.: S. Gronowitz), Wiley, New York, 1985, pp. 697-705.
3. a) H. Kotsuki, S. Kitagawa, H. Nishizawa, T. Tokoroyama, J. Org. Chem. 1978, 43, 1471;
4. b) H. Kotsuki, H. Nishizawa, S. Kitagawa, M. Ochi, N. Yamasaki, K. Matsuoka, T. Tokoroyama, Bull. Chem. Soc. Jpn. 1979, 52, 544.
5. Organic Synthesis at High Pressures (Eds.: K. Matsumoto, R. M. Acheson), Wiley, New York, 1991.
6. Clean Solvents (Eds.: M. A. Abraham, L. Moens), American Chemical Society, Washington, DC, 2002.
7. a) K. E. Myers, K. Kumar, J. Am. Chem. Soc. 2000, 122, 12025;
8. b) G. Jenner, B. Gacem, J. Phys. Org. Chem. 2003, 16, 265.
9. K. Tanaka, Solvent-free Organic Synthesis, Wiley-VCH, Weinheim, 2003.
10. At the end of the reaction most of 3 was precipitated in the mixture as a result of its very low solubility. Typical experimental procedure: A mixture of thiophene (1.495 g, 17.8 mmol) and maleic anhydride (441 mg, 4.5 mmol) was placed in a teflon reaction vessel (volume: 3.9 mL), and the mixture was treated at 0.8 GPa and 100 °C for 2 days. After cooling the reaction mixture and releasing the pressure, the excess of thiophene was evaporated and the crude solid product (785 mg) was purified by column chromatography on silica gel (hexane/AcOEt = 1:1) to give exo adduct 3 (761 mg, 93%) as a colorless solid.
11. Theoretical calculations have revealed a very large activation energy for thiophene cycloaddition reactions: a) B. S. Jursic, Z. Dzravkovski, S. L. Whittenburg, J. Phys. Org. Chem. 1995, 8, 753;
12. b) B. S. Jursic, J. Mol. Struct. THEOCHEM 1998, 454, 105.
13. 3): δ = 50.12 (× 2), 53.89 (× 2), 126.54 (× 2), 128.87, 129.18 (× 2), 131.85, 139.94 (× 2), 175.17 ppm (× 2).
14. 3): δ = 34.26, 46.99, 51.27, 52.20, 54.55, 137.09, 140.17, 173.69 ppm.
15. The acrylic dienophiles have a strong tendency to polymerize at high pressure, and this can sometimes be very dangerous. Particular attention should be paid to these reactions.