CO₂ Conversion into Esters by Fluoride‐Mediated Carboxylation of Organosilanes and Halide Derivatives

Abstract

A one-step conversion of CO2 into heteroaromatic esters is presented under metal-free conditions. Using fluoride anions as promoters for the C-Si bond activation, pyridyl, furanyl, and thienyl organosilanes are successfully carboxylated with CO2 in the presence of an electrophile. The mechanism of this unprecedented reaction has been elucidated based on experimental and computational results, which show a unique catalytic influence of CO2 in the C-Si bond activation of pyridylsilanes. The methodology is applied to 18 different esters, and it has enabled the incorporation of CO2 into a polyester material for the first time.

Synthesis of Aromatic Sulfones from SO2 and Organosilanes Under Metal‐free Conditions

“…Organosilanes are very mild nucleophiles and a fluoride source or a base is needed to activate the weakly polar C−Si bond and facilitate transmetallation to a metal catalyst . Interestingly, we have recently reported the fluoride‐mediated carboxylation of heteroarylsilanes with CO 2 , where CO 2 acts both as a reagent and as a catalyst . Reasoning that SO 2 is a stronger Lewis acid than CO 2 , we have sought to promote the sulfonylation of 2‐(trimethylsilyl)pyridine ( 1 ) with the SO 2 adduct DABSO.…”

Copper‐Catalyzed Carboxylation of Aryl‐ and Alkenyltrialkoxysilanes

“…In their hypothesis, the electron‐withdrawing moiety stabilizes the aryl carbanions that were generated from the fluoride‐mediated desilylation process. More recently, Cantat achieved the carboxylation of heteroarylsilanes, in which the silicon moiety was positioned ortho to the heteroatoms . In an attempt to develop a more general carboxylation method, Kondo utilized phosphazenium salts as catalysts .…”

Photocatalytic C–H silylation of heteroarenes by using trialkylhydrosilanes

“…Heteroaryltrialkylsilanes, especially the electron-deficient heteroaryltrialkylsilanes, represent a class of promising therapeutic agents with interesting biological properties (see the representative examples shown in Scheme 1). 1–4 Moreover, these organosilicon functionalities serve as versatile heteroaryl handles for complex molecule synthesis owing to their high air and moisture stability, low toxicity, and ease of manipulation 5–9…”