Nuclear Magnetic Resonance Spectroscopy. Cyclopropane Derivatives

Chemical shifts and coupling constants have been determined from the analysis of proton nuclear magnetic resonance spectra for a series of cyclopropane derivatives. The geminal and vicinal cyclopropyl couplings have opposite signs. Additional ^(13)C-H coupling constants have been obtained for cyclopropanes which support the conclusion that the hybridization of the carbon-hydrogen bonding orbitals in cyclopropanes is close to sp. The chemical shifts for several cyclopropane hydrocarbons seem consistent with a ring-current effect.