Carboxylation of Phenols with CO₂ at Atmospheric Pressure

Abstract

A convenient and efficient method for the ortho-carboxylation of phenols under atmospheric CO2 pressure has been developed. This method provides an alternative to the previously reported Kolbe-Schmitt method, which requires very high pressures of CO2 . The addition of a trisubstituted phenol has proved essential for the successful carboxylation of phenols with CO2 at standard atmospheric pressure, allowing the efficient preparation of a broad variety of salicylic acids.

Transition Metal‐Free CO2 Fixation into New Carbon–Carbon Bonds

“…[25] They found that the use of 2,4,6-trimethylphenol( XI)a sr eaction mediator greatlye nhances the reactivity of the system, avoiding the high pressures commonly required in this kind of phenol carboxylation. [25] They found that the use of 2,4,6-trimethylphenol( XI)a sr eaction mediator greatlye nhances the reactivity of the system, avoiding the high pressures commonly required in this kind of phenol carboxylation.…”

“…Phenol and other aromatic alcohols are efficiently carboxylated in ortho positionb yu sing 4equivalents of NaH (X)u nder Scheme11. [25] Scheme10. [24] Scheme12.…”

“…[25] Scheme15. Proposed reaction mechanism of the o-carboxylation phenol derivatives with CO 2 developed by Larrosaa nd co-workers.…”

C−H Carboxylation of Aromatic Compounds through CO2 Fixation

“…In 2016, the Larrosa group developed the first protocol for Kolbe–Schmitt‐type carboxylations that occur efficiently under an atmospheric pressure of CO 2 12. The use of NaH as the base avoided the undesired formation of H 2 O, and allowed the reaction to proceed in a one‐pot process without isolation of the phenoxide precursor.…”

Palladium‐Catalyzed Inert C−H Bond Activation and Cyclocarbonylation of Isoquinolones with Carbon Dioxide Leading to Isoindolo[2,1‐b]isoquinoline‐5,7‐Diones

“…) in DMF (N, N-dimethylformamide) (2.0 mL) at 150°C for 20 h, and the desired product 12-phenylisoindolo [2,1-b] isoquinoline-5,7-dione (2 a) was obtained in 33% yield ( Table 1, entry 1). The effect of catalysts was firstly investigated, which revealed that Pd(OAc) 2 was the most effective catalyst (36%, entries [1][2][3][4]. No product was observed in the absence of catalyst or base (entries [5][6].…”