Is cyclobutadiene really highly destabilized by antiaromaticity?
The high energy of cyclobutadiene (CBD) is not due primarily to "anti-aromaticity," but rather to angle strain, torsional strain, and Pauli repulsion between the parallel CC bonds. Estimations including block-localized wavefunction (BLW) computations conclude that the enormous ring strain (ca. 60 kcal mol(-1)) far exceeds its antiaromatic destabilization (only 16.5 kcal mol(-1)).
Department of Chemistry, Center for Computational Quantum Chemistry, University of Georgia, Athens, GA 30602, USA. judywu@ccc.uga.edu
Judy I-Chia
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Wu
Yirong
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Mo
Francesco Alfredo
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Paul
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von Ragué Schleyer