Circular dichroism of tocopherols versus tocotrienols

✍ Scribed by Francesco Mazzini; Gennaro Pescitelli; Lorenzo Di Bari; Thomas Netscher; Piero Salvadori

• Book ID: 102796522
• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 575 KB
• Volume: 21
• Category: Article
• ISSN: 0899-0042
• DOI: 10.1002/chir.20591

✦ Synopsis

Abstract

Vitamin E is an essential nutrient of still increasing economic importance. Vitamin E derivatives include many nonracemic chiral compounds whose chirooptical characterization is scarcely described in the literature. We report the CD spectra of δ‐tocopherol and its unsaturated analog δ‐tocotrienol. TDDFT calculations demonstrate that the weak CD of δ‐tocopherol is determined by the helicity of dihydropyrane ring. In addition, the moderate CD of δ‐tocotrienol is due to the exciton interaction between the aromatic ring and the closest alkene group. Direct exciton‐coupled CD calculations on structures generated by two different conformational sampling approaches reveal that, although such exciton coupling is expected to be weak, it is sufficient to explain the spectral differences between tocopherol and tocotrienol. Chirality, 2009. © 2008 Wiley‐Liss, Inc.