Fig. 8. (a) Differences in free energies and enthalpies of TSSs from the non-selective background and enantioselective DA cycloadditions computed using multiple model chemistries and the 6-31G(d) basis set (see ESI† (Comp studies) for details). Energies shown in kcal mol–1 relative to separated reactants. (b) Plots of yield and enantiomeric and diastereomeric excess as a function of temperature for DAL reactions employing diene 13d and acid chloride 5. Enantiomeric excess was determined by chiral-phase HPLC and is only shown for the major (endo) diastereomer (ee values for the exo diastereomer were similar).
