Inquiry of the reaction paths in thermal retro-Diels-Alder reactions in the gas phase: Theoretical study on the concerted and stepwise elimination mechanisms of cyclohexenes

Calculated parameters from B2PLYP/6-31+G(d,p) of gas-phase elimination of selected cyclohexenes are in good agreement with experimental work in gas phase. Apparently, the mechanism of retro-Diels-Alder decomposition is a concerted molecular reaction.