Solution conformation of longifolene and its precursor by NMR and ab initio calculations.
We describe the conformation and stereospecific 1H and 13C chemical shift assignments of longifolene 1 and its penultimate precursor 2 through the combined use of ab initio calculations and experimental NMR techniques. The predicted stable conformation for both compounds was similar and adopts a twisted chair conformation at the seven-membered ring where C4 lies on top of the exocyclic double bond. The calculated chemical shifts for the stable conformation agree well with the experimental values.
Subramaniam
Gopal
G
Department of Chemistry and Biochemistry, Queens College of CUNY, Flushing, NY 11367, USA. gopal.subramaniam@qc.cuny.edu
Karimi
Sasan
S
Phillips
David
D
D002247:Carbon Isotopes / Q000032:analysis; D006859:Hydrogen / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D012717:Sesquiterpenes / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry
D002247:Carbon Isotopes; D012717:Sesquiterpenes; D012996:Solutions; C035607:longifolene; D006859:Hydrogen