Theoretical investigation on facial and stereoselectivity in Diels‐Alder cycloadditions of maleic anhydride to dissymmetric cage‐annulated cyclohexa‐1,3‐dienes

Abstract

AbstractThe facial and stereoselectivity of the polar Diels‐Alder (P‐DA) reaction of dissymmetric cage‐annulated cyclohexa‐1,3‐diene,10,12,13,14‐tetrachloro‐11,11‐dimethoxy‐hexacyclo [7.5.1.01,6.06,13.08,12.010,14]pentadeca‐2,4‐diene‐7,15‐dione with maleic anhydride, has been theoretically investigated using density functional theory (DFT) method at B3LYP/6‐31G(d) level. Within possible 4 reaction pathways of this P‐DA reaction explored, the anti/endo reactive channel is found to be favored both kinetically and thermodynamically according to calculated results, in compatible with experimental findings. The analysis of DFT‐based global and local reactivity indices of reagents at the ground state enables us to correctly explain the polar nature of these DA reactions' pathways. The presence of steric interactions appeared at exo approaches and nonclassical hydrogen bond interactions seen at endo ones has significant effect on both facial and stereoselectivity of the corresponding DA reaction.