title: A DFT analysis of thermal decomposition reactions important to natural products.
abstract: The thermal decomposition reactions of several important natural flavor and fragrance chemicals have been investigated using density functional theory (DFT, B3LYP/6-31G*). Retro-aldol reactions of glucose, fructose, hernandulcin, epihernandulcin, [3]-gingerol, and [4]-isogingerol; retro-carbonyl-ene reactions of isopulegol, lavandulol, isolyratol, and indicumenone; and pyrolytic syn elimination reactions of linalyl acetate, alpha-terpinyl acetate, and bornyl acetate, have been carried out. The calculations indicate activation enthalpies of around 30 kcal/mol for the retro-aldol reactions and for retro-carbonyl-ene reactions, comparable to pericyclic reactions such as the Cope rearrangement and electrocyclic reactions, and therefore important reactions at elevated temperatures (e.g., boiling aqueous solutions, gas-chromatograph injection ports). Activation enthalpies for pyrolytic eliminations are around 40 kcal/mol and are unlikely to occur during extraction or GC analysis.
authors.affiliation: Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA. wsetzer@chemistry.uah.edu
authors.forename: William N
authors.initials: WN
authors.lastname: Setzer
mesh_terms: D001688:Biological Products; D002241:Carbohydrates / Q000737:chemistry; D003198:Computer Simulation; D008956:Models, Chemical; D015394:Molecular Structure
chemical_list: D001688:Biological Products; D002241:Carbohydrates