From one to two CO2 molecules: controllable divergent synthesis of formate esters and carbonates

Abstract

The selective transformation of carbon dioxide (CO₂) into multiple high-value products from a unified set of starting materials represents a compelling yet underexplored frontier in sustainable synthesis. Herein, we report a controllable divergent strategy that enables the selective synthesis of either formate esters or unsymmetrical carbonates from CO₂, organic halides, and phenylsilane through precise modulation of the reaction conditions. Notably, the two pathways differ fundamentally in their engagement of CO₂: the formate pathway involves a single molecule of CO₂ undergoing two-electron reduction to a silyl formate intermediate, whereas the carbonate pathway incorporates two molecules of CO₂, wherein one is reduced by six electrons to a methoxysilyl species, and the other serves as the electrophilic carbonyl source. The protocols feature a simple procedure, broad substrate scope and excellent functional group tolerance. This work establishes a new paradigm for programmable selectivity in CO₂ valorization, offering divergent access to two important classes of compounds from a common feedstock.