Fig. 4: DFT-computed Gibbs free energies.
From: A [6+4]-cycloaddition adduct is the biosynthetic intermediate in streptoseomycin biosynthesis
a the Cope rearrangement of 12 and the subsequent Alder-ene reaction; b the Cope rearrangement of 10; c transition-state structures (Carbon: gray, Hydrogen: white, Oxygen: red, and distances are shown in Å).
