Stabilization and first direct spectroscopic evidence of the o-quinone methide derived from vitamin E

Organic Letters

Volumn 4, Issue 24, 2002, Pages 4285-4288

  Rosenau, Thomas ^a   Potthast, Antje ^a   Elder, Tom ^b   Kosma, Paul ^a  

^a UNIVERSITY OF NATURAL RESOURCES AND LIFE SCIENCES   (Austria)

^b AUBURN UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

ALPHA TOCOPHEROL; INDOLE DERIVATIVE; QUINONE DERIVATIVE; QUINONE METHIDE;

ARTICLE; CHEMICAL STRUCTURE; CHEMISTRY; DRUG STABILITY; KINETICS; NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY; OXIDATION REDUCTION REACTION; SYNTHESIS; TEMPERATURE;

DRUG STABILITY; INDOLEQUINONES; INDOLES; KINETICS; MAGNETIC RESONANCE SPECTROSCOPY; MOLECULAR STRUCTURE; OXIDATION-REDUCTION; QUINONES; TEMPERATURE; VITAMIN E;

EID: 0037191616     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol026917f     Document Type: Article

References (18)

1. Van de Water, R. W.; Pettus T. R. R. Tetrahedron 2002, 58, 5367-5405.
2. (a) Machlin, L. J. Vitamin E: A Comprehensive Treatise; Marcel Dekker Inc.: New York, 1980.
3. (b) Parkhurst, R. M.; Skinner, W. A. Chromans and Tocopherols. In Chemistry of Heterocyclic Compounds; Ellis, G. P., Lockhardt, I. M., Eds.; Wiley: New York, 1981; Vol. 36.
4. (a) Schudel, P.; Mayer, H.; Metzger, J.; Rüegg, R., Isler, O. Helv. Chim. Acta 1963, 46, 636-649.
5. (b). Fales, H. M. J. Chem. Soc., Perkin Trans 2 1990, 1005.
6. Bolon, D. A. J. Org. Chem. 1970, 35, 3666-3671.
7. Rosenau, T.; Habicher, W. D. Tetrahedron 1995, 51, 7919-7926.
8. NMMO is used on the industrial scale as a solvent for cellulose to produce the Lyocell fiber type. The cellulose/NMMO mixtures need to be stabilized during dissolution and further processing against degradation reactions, before being spun. For a review, see: Rosenau, T.; Potthast, A.; Sixta, H.; Kosma, P. Prog. Polym. Sci. 2001, 26(9), 1763-1837.
9. (a) Rosenau, T.; Potthast, A.; Elder, T.; Lange, T.; Sixta, H.; Kosma, P. J. Org. Chem. 2002, 67(11), 3607-3614.
10. (b) Rosenau, T.; Potthast, A.; Hofinger, A.; Kosma, P. Angew. Chem., Int. Ed. 2002, 41(7), 1171-1173.
11. The rate constant for the reaction of 2 to 4 is about 10 times larger than that of the spirodimerization to 3. As ethyl vinyl ether is added in more than a 100-fold molar excess relative to 1, the trapping reaction becomes about 3 orders of magnitude faster than the dimerization, so that the formation of spiro-dimer 3 after addition of ethyl vinyl ether into the reaction system can be neglected.
12. As a result of the ring current effect, the resonances of the protons at C-7a, C-8b, and C-4 experience a downfield shift in tocopherol (1), which seems still to be operating in the complex between 2 and 5 (Table 1).
13. 13C NMR-Spektroskopie; Georg Thieme Verlag: Stuttgart, 1984; p 370.
14. 13C resonances of quinoid carbons are usually found between 180 and 195 ppm. See: ref 10, p 281.
15. 2 group is not a resonance form of quinoid 2, as rotating the methylene group breaks the resonance.
16. For the issue of planar and perpendicular benzyl cations and the corresponding rotational barriers, see: Dorigo, A. E.; Li, Y.; Houk, K. N. J. Am. Chem. Soc. 1989, 111, 6942-6948.
17. 2=CH-OEt addition. No other compounds than 3 and 4 were detected.
18. Rosenau, T.; Potthast, A.; Habicher, W. D.; Kosma, P. Synlett 1999, 3, 291-294.