Magnetic non-equivalence in nuclear resonance. Part V. Geminal allenic protons

Abstract

Magnetic non-equivalence in the chemical-shift sense of geminal allenic nuclei, is introduced into allenic bromo-ketones by an asymmetric carbon atom in the δ position with respect to the terminal methylene.

The magnitude of the chemical-shift difference between anisochronous protons depends on the nature and concentration of the solvent. This behaviour allows the direct determination of the geminal coupling constant.