How Dihalogens Catalyze Michael Addition Reactions.

ABSTRACT: We have quantum chemically analyzed the catalytic effect of dihalogen molecules (X₂ =F₂ , Cl₂ , Br₂ , and I₂ ) on the aza-Michael addition of pyrrolidine and methyl acrylate using relativistic density functional theory and coupled-cluster theory. Our state-of-the-art computations reveal that activation barriers systematically decrease as one goes to heavier dihalogens, from 9.4 kcal mol^-1 for F₂ to 5.7 kcal mol^-1 for I₂ . Activation strain and bonding analyses identify an unexpected physical factor that controls the computed reactivity trends, namely, Pauli repulsion between the nucleophile and Michael acceptor. Thus, dihalogens do not accelerate Michael additions by the commonly accepted mec

SUBMITTER: Hamlin TA 

PROVIDER: S-EPMC6617756 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature