Theoretical insights of p-Block compounds in ring expansion reactions and catalysis

Abstract

Chapter 1 illustrates the potential applications of ring expansion reactions in boron chemistry. We start with a computational analysis regarding the carbon monoxide (CO) insertion reaction in borole derivatives that has already been validated experimentally. We then use isosterism to transpose this type of reactivity to the 1,2,5-azadiborolidine ring, a boracycle that has not previously been investigated in this context. Here, we demonstrate that CO insertion occurs via a ring expansion mechanism governed by electronic, not steric, factors. Furthermore, we predict the ease of this reaction under mild conditions for 1,2,5-tritert-butyl-1,2,5-azadiborolidine in a solution of n-pentane. In Chapter 2, we investigate triethanolamine borate, a polycyclic compound characterised by a transannular bond between a boronic acid fragment and a tertiary amine. This atrane is known to catalyse the cycloaddition of epoxides and carbon dioxide (CO2). In this study, we computationally elucidate the reaction mechanism of this transformation and clarify the roles played by the catalyst and cocatalysts. Having revealed the catalyst’s mechanism of action, we proceeded to enhance its catalytic activity by atom substitutions, thus performing predictive catalysis. This results in the construction of a new family of atranes with potential applications in the ring-opening reaction of epoxides.