engleski

Diels-Alder Cycloadditions of 1, 3-Cyclohexadien-4, 5-diones (o-benzoquinones). Part II. A High Level Computational Study of their Stereospecificities

Ab initio and DFT quantum chemical calculations have been applied to a study of Diels-Alder reactions of o-benzoquinone as diene and norbornadiene as dienophile. Transition states for these reactions are located and activation energies estimated. The prefered exo- - facial selectivities and exo, endo- stereospecificities exhibited in these cycloadditions are readily predicted using RHF/3-21G or higher levels of calculations. Differences between experimentally observed results and calculations may be explained by the postulation of a second, nonconcerted biradical mechanism leading to formation of hetero Diels-Alder products.

calculations; DFT; abinitio; cycloadditions; Diels-Alder; norbornene

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