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 unsymmetric 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 via six electrons to a methoxysilyl species and the other serves as the electrophilic carbonyl source. The protocols feature 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.