Reaction Energetics & Diels-Alder Reaction Profiles for Enediones
and Decalines by Means of DFT
Hugo Semrád and Markéta Munzarová
Department of Chemistry, Masaryk University
The original goal of our study was an energy comparison between isomers of several forskolin
derivatives. Relative stabilities of decalines and related enediones were assesed with respect to
cis/trans isomerism at the ring junction as well as with respect to axial/equatorial position of tertbutylsilyloxy
substituent.
A comparison with experiment motivated us to perform a reaction path analysis for enedione
synthesis from cis-(tert-butyldimethylsilyloxy)buta-1,3-diene with p-benzoquinone, which has been
substitued by methyl and phenyl/naphthyl groups in the positions 2 and 5, respectively. Our results
demonstrate that all energy barriers are quite close to each other (it is about 19–23 kcal mol−1
). The
mechanism of the substituted p-benzoquinone addition to butadiene appears to be a non-concerted
one.
All calculations were performed by means of density functional theory (DFT) employing the
B3LYP/6-31G* implementation along with the SMD implicit solvation model of toluene and
tetrahydrofuran.
Figure 1: Example of the synthesis within Diels-Alder reaction.