Unravelling the Mechanism and Governing Factors in Lewis Acid and Non-Covalent Diels-Alder Catalysis: Different Perspectives.

In the current literature, many non-covalent interaction (NCI) donors have been proposed that can potentially catalyze Diels-Alder (DA) reactions. In this study, a detailed analysis of the governing factors in Lewis acid and non-covalent catalysis of three types of DA reactions was carried out, for which we selected a set of hydrogen-, halogen-, chalcogen-, and pnictogen-bond donors. We found that the more stable the NCI donor-dienophile complex, the larger the reduction in DA activation energy.

Reactivity of a N-Coordinated Germylene-Borane Complex: From Ge→B to Ge→Ga Coordination.

Reactivity studies of the Ge →B complex L(Cl)Ge⋅BH (1; L=2-Et NCH -4,6-tBu -C H ) were performed to determine the effect on the Ge →B donation. N-coordinated compounds L(OtBu)Ge⋅BH (2) and [LGe⋅BH ] (3) were prepared. The possible tuning of the Ge →B interaction was proved experimentally, yielding compounds 1-PPh -8-(LGe)-C H (4) and L(Cl)Ge⋅GaCl (5) without a Ge →B interaction.

Hydrogen-Bond-Assisted Diels-Alder Kinetics or Self-Healing in Reversible Polymer Networks? A Combined Experimental and Theoretical Study.

Diels-Alder (DA) cycloadditions in reversible polymer networks are important for designing sustainable materials with self-healing properties. In this study, the DA kinetics of hydroxyl-substituted bis- and tetrafunctional furans with bis- and tris-functional maleimides, both containing ether-functionalized spacers, is investigated by modelling two equilibria representing the and cycloadduct formation. Concretely, the potential catalysis of the DA reaction through hydrogen bonding between hydroxyl of the furans and carbonyl of the maleimides or ether of the spacers is experimentally and theoretically scrutinized.