Absolute configuration of (-)-myrtenal by vibrational circular dichroism.
The VCD spectrum of the monoterpene (-)-myrtenal (1) was compared with theoretical spectra using ab initio density functional theory (DFT) calculations at the B3LYP/6-31G(d,p), B3LYP/6-31G+(d,p), B3LYP/6-311G+(d,p), B3LYP/DGDZVP, and B3PW91/DGTZVP levels of theory. Conformational analysis of 1 indicated that the lowest energy conformer was s-trans-C2-C10, which contributes more than 98.5% to the total conformational population regardless of the employed level of theory. The use of a recently developed confidence level algorithm demonstrated that VCD spectra calculated for the main conformer, using the indicated hybrid functionals and basis set, gave no significant changes, from where it follows that B3LYP/DGDZVP calculations provide a superior balance between computer cost and VCD spectral accuracy. The DGDZVP basis set demanded around a quarter the time than the 6-311G+(d,p) basis set while providing similar results. The spectral comparison also provided evidence that the levorotatory enantiomer of myrtenal has the 1R absolute configuration.
Burgueño-Tapia
Eleuterio
E
Departamento de Química Orgánica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala, Col. Santo Tomás, México, D.F. 11340, Mexico.
Zepeda
L Gerardo
LG
Joseph-Nathan
Pedro
P
D000465:Algorithms; D000081008:Bicyclic Monoterpenes; D002942:Circular Dichroism; D008958:Models, Molecular; D008968:Molecular Conformation; D013729:Terpenes / Q000737:chemistry*; D014732:Vibration
D000081008:Bicyclic Monoterpenes; D013729:Terpenes; C061545:myrtenal