Supporting the NMR-based empirical rules to determine the stereochemistry and halogen regiochemistry of vicinal vinyl dihalides. Naturally occurring monoterpenes as chemical models

Two novel monoterpenes, and , containing an unusual 1,2-bromochloro vinylic portion, were analyzed to study the influence of γ-substituents on the C-1 and H-1 chemical shifts of the 1,2-dihalo vinylic residue. This study reinforces the validity of the empirical rules based on 13C and 1H NMR spectroscopy as a helpful tool for determining the regio- and stereochemistry of substituted vicinal vinyl dihalides.