A Molecular Electron Density Theory Study of the Competitiveness of Polar Diels⁻Alder and Polar Alder-ene Reactions.

ABSTRACT: The competitiveness of the BF₃ Lewis acid (LA) catalyzed polar Diels⁻Alder (P-DA) and polar Alder-ene (P-AE) reactions of 2-methyl-1,3-butadiene, a diene possessing an allylic hydrogen, with formaldehyde has been studied within the Molecular Electron Density Theory (MEDT) at the MPWB1K/6-311G(d,p) computational level. Coordination of BF₃ LA to the oxygen of formaldehyde drastically accelerates both reactions given the high electrophilic character of the BF₃:formaldehyde complex. As a consequence, these reactions present a very low activation enthalpy-less than 2.2 kcal·mol-1-thus becoming competitive. In dioxane, the P-AE reaction is slightly favored because of the larger polar character of the corresponding transition state structure (TS). In addition, the Prins reaction between hexahydro

SUBMITTER: Domingo LR 

PROVIDER: S-EPMC6222353 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature