Stereochemistry of the Four-Centered Gas-Phase Dehydrohalogenation Reaction

Article abstract of DOI:10.1021/j100239a017

The stereochemistry of the gas-phase four-centered dehydrohalogenation reaction has been determined.Deuterium analysis of the 2-butene isomers formed by the thermal decomposition of threo- and erythro-2-bromo-3-deuteriobutane proves that elimination is principally via a syn transition state; i.e., the hydrogen and halogen are removed from the same side of the carbon-carbon bond.The results show that the contribution of anti stereochemical transition state complexes is small, perhaps zero.Primary and secondary deuterium kinetic isotope effects were 2.11 +/- 0.31 and 0.98 +/- 0.12 respectively for erythro-2-bromo-3-deuteriobutane, and 2.07 +/- 0.24 and 1.02 +/- 0.13 respectively for threo-2-bromo-3-deuteriobutane at 590 K.