Reaction Pathways in Carbonates and Esters

Area of Science:

• Organic Chemistry
• Physical Chemistry
• Green Chemistry

Background:

• Carbonates and esters exhibit complex reactivity influenced by various catalytic mechanisms.
• Understanding the interplay between acyl and alkyl cleavage is crucial for predicting reaction outcomes.
• Existing literature provides experimental data on these reactions, necessitating a unifying theoretical framework.

Purpose of the Study:

• To analyze and compare the reactivity of carbonates and esters.
• To propose a theoretical model for the intertwined base- and acid-catalyzed mechanisms (B_Ac2/B_Al2, A_Ac2/A_Al2, A_Al1).
• To investigate the role of entropic and anchimeric effects in carbonate reactions.

Main Methods:

• Comprehensive review and analysis of existing experimental data from scientific literature.
• Development of a theoretical model to explain energy profiles of competing reaction mechanisms.
• Comparative analysis of carbonate and ester reactivity under various catalytic conditions.

Main Results:

• A theoretical model was proposed, outlining energy profile differences for B_Ac2/B_Al2 and A_Ac2/A_Al2/A_Al1 mechanisms.
• Carbonate reactions are driven by precise sequences of B_Ac2-B_Al2 or A_Al2-A_Ac2 mechanisms.
• Entropic and anchimeric effects reduce Gibbs activation energy, enabling transformations at lower temperatures and requiring only catalytic base amounts.

Conclusions:

• Carbonate chemistry involves tightly interconnected reaction pathways crucial for product formation.
• Specific effects like cyclization and anchimeric assistance significantly lower activation energy barriers.
• Carbonates offer greener synthesis alternatives compared to chlorine chemistry, reducing environmental impact.