Mechanistic investigation of [2+2] cycloaddition reactions of keteniminium salts :|probing their applications in synthesis

Abstract

This thesis has two main parts, involving theoretical studies based on Density Functional Theory (DFT), related to [2+2] cycloaddition reactions of keteniminium salts, (KI)s, and their applications in industry. In the first part, the [2+2] cycloaddition reactions between KIs and alkenes were modeled to examine the mechanistic aspects of the reaction with respect to varying substitution patterns of alkenes. Moreover, the reactivity of KIs toward [2+2] cy cloaddition was evaluated by differing substitution on KIs. Energetic analysis and conceptual DFT methods were used to rationalize the difference in reactivity of KIs. This study aims to provide know-how to experimental studies that use keteniminium salts as key intermediates. In the second part, DFT studies conducted in collaboration with industry were presented. First, the reaction mechanism that leads to the formation of zealactone 1a/b was modeled. Second, the reactivity of vinyl-acetylenyl ketene toward olefins was compared. Finally, geometry optimizations of KI-enamine structures were performed to analyze reactivity patterns in relation to coplanarity