Modes of neighbouring group participation by the methyl selenyl substituent in β-methylselenylmethyl-substituted 1-phenylethyl carbenium ions.
Selenium substituents which are disposed β to an electron deficient centre, such as a carbocation p-orbital, or the π* orbital of an electron deficient p-system, interact in a stabilising way by a combination of C-Se hyperconjugation (σ(Se-C)-π* interaction), and a through-space homoconjugative n(Se)-π* interaction. The relative importance of these two modes of interaction is dependant on the electron demand of the cation, with hyperconjugation predominating for low electron demand systems, and the n(Se)-π* interaction predominating for high electron demand cations.
School of Chemistry and BIO-21 Institute, University of Melbourne, Parkville 3010, Victoria, Australia. whitejm@unimelb.edu.au.
Benjamin L
BL
Harris
Jonathan M
JM
White
D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D016566:Organoselenium Compounds / Q000737:chemistry*; D011726:Pyridinium Compounds / Q000737:chemistry*; D011789:Quantum Theory
D016566:Organoselenium Compounds; D011726:Pyridinium Compounds