STRUCTURE ASSIGNMENTS IN POLYSUBSTITUTED ETHYLENES BY NUCLEAR MAGNETIC RESONANCE

An nmr technique is described by which structures can be assigned to many di- and trisubstituted ethylenes simply from a knowledge of the vinyl proton resonance positions in the compound under study. The technique depends on the additivity of vinyl substituent shielding effects on the vinyl protons present. Tables of substituent shielding constants (σ values) for several common functional groups are presented, and various methods for obtaining σ values are outlined. Solutions to several structural assignment problems are presented, including cases in which steric and electronic interactions between substituents must be taken into account. © 1969, American Chemical Society. All rights reserved.