Michael addition of amines to α-ß unsaturated esters

The rate of Michael addition of primary amines to acrylates under different initial conditions was investigated. An acceptable agreement between different mathematical rate expressions was observed. The maximum rate was obtained in protic and polar solvents. The maximum temperature that equivalent amounts of primary amines and acrylates undergo the Michael addition without excessive formation of amide byproducts was about 50°C. The reaction rate was highly affected by the steric hindrance of the amine. Aromatic amines did not have a significant rate of reaction with simple acrylates. Lewis acid catalysts significantly increased the rate. The highest rate increase due to Lewis acid catalysts was obtained with aromatic and secondary amines. The rate was also affected by the structure of the Michael acceptor. The order of reactivity for amine addition to unsaturated esters was acrylates \u3e maleates \u3e fumarates \u3e methacrylates. A polar concerted mechanism with six-member cyclic transition state for the nucleophilic attack of amine on the Michael acceptor followed by protic medium assisted enol-keto tautomerization to yield the final product was proposed. Macrocycles based on the Michael addition of primary amines and multi-functional acrylates were synthesized. These macrocycles were also formed as byproducts during polymer synthesis. Optimization of conditions resulted in the formation of macrocycles in high yield --Abstract, page iii