Thermochemical Study of 1-Acetyl Vinyl p-Nitrobenzoate: Vinyl Bond Enthalpy in Captodative Olefins

Abstract

Captodative olefins are highly reactive and selective substrates in Diels-Alder and 1,3-dipolar cycloadditions. Seeking an explanation of this fact based on molecular energetics, the thermochemical analysis of 1-acetyl vinyl p-nitrobenzoate, a captodative olefin, has been performed using semi-micro-combustion calorimetry, effusion measurements through a quartz crystal microbalance, and differential scanning calorimetry. The molar standard combustion energy and enthalpy as well as the molar standard formation enthalpy are reported along with sublimation and melting enthalpies. From these data, experimental formation enthalpy of the gas-phase is derived and compared with the theoretical value calculated through the density functional theory procedure. The olefinic bond enthalpy is also computed from experimental data, and the relevance of the results is discussed.

Conjugate addition between syringol and a captodative olefin catalyzed by BF3

“…However, the high reactivity and regioselectivity of alkene 2 shown in cycloadditions[4a,6] and conjugate additions seem to be associated to the long‐distance inductive effect of the aroyloxy substituents . Recent thermochemical studies on 2 have contributed to determine properties such as, the formation enthalpies, heat capacity, and sublimation enthalpy in the gas phase . They measured the gas‐phase formation enthalpy of 2 , and it was compared computationally with its enthalpy of formation.…”