A molecular electron density theory study of hydrogen bond catalysed polar Diels–Alder reactions of α,β-unsaturated carbonyl compounds

Domingo, L.Pérez, P.Ríos-Gutiérrez, M.Aurell, M.2024-09-102024-09-102024-06Tetrahedron Chem, Volume 10 , June 2024, 1000642666-951Xhttps://repositorio.unab.cl/handle/ria/60036TEXTO COMPLETO EN INGLÉSThe hydrogen bond (HB) catalysed Diels-Alder (DA) reactions of acrolein with cyclopentadiene have been investigated within the Molecular Electron Density Theory (MEDT) at the ωB97X-D/6-311G(d,p) computational level. The formation of HBs increases the electrophilicity of these species, suggesting an acceleration of these polar Diels-Alder (P-DA) reactions with forward electron density flux. Formation of one or two HBs with acrolein decreases the activation energies of the HB-catalysed P-DA reactions by 1.7 (methanol) and 4.0 (squaramide) kcal·mol−1, with the corresponding DA reactions exhibiting low endo stereoselectivity. These HB-catalysed DA reactions proceed through non-concerted one-step mechanisms via asynchronous transition state structures (TSs). An Interacting Quantum Atoms (IQA) energy partitioning analysis of the TSs indicates that the intra-atomic stabilization of the acrolein framework, coupled with the increase of the global electron density transfer, plays a crucial role in reducing the activation energies of these HB-catalysed DA reactions.enDiels-Alder reactionsHydrogen bondsCatalysisStereoselectivityMolecular electron density theoryA molecular electron density theory study of hydrogen bond catalysed polar Diels–Alder reactions of α,β-unsaturated carbonyl compoundsArtículoAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttps://doi.org/10.1016/j.tchem.2024.100064