engleski

Benzocyclobutene: The Impact of Fusing a Strained Ring onto Benzene

The gas-phase acidities of the two aromatic sites in benzocyclobutene were measured in a Fourier transform mass spectrometer using kinetic technique (i.e. DePuy method). Fusion of a cyclobutane ring onto benzene is found to have slight acidifying effect at the alpha position (3.2 +/- 1.7 kcal/mol) and little, if any, influence on the beta site (0.8 +/- 1.9 kcal/mol). Energetic data (acidity, electron affinity and C-H bond dissociation energy) for the benzylic position were obtained via the bracketing technique and application of a thermodynemic cycle. Differences in the reactivities of the three conjugate bases also were explored. Ab initio and DFT calculations were carried out to provide geometries, energies and insights into the carbanions' electronic structures.

Benzocyclobutene; acidity; Mass Spectrometry; Ion Cyclotron Resonance; electronic structure; ab initio; quantum-chemical calculations

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