One‐Pot Conversion of Carbon Dioxide, Ethylene Oxide, and Amines to 3‐Aryl‐2‐oxazolidinones Catalyzed with Binary Ionic Liquids

Abstract

An effective one‐pot method for the conversion of carbon dioxide, ethylene oxide, and amines to 3‐aryl‐2‐oxazolidinones has been developed. This one‐pot method consists of two parallel reactions and a subsequent cascade reaction between the two products of the corresponding parallel reactions. Notably, the binary ionic liquids of 1‐butyl‐3‐methyl‐imidazolium bromide and 1‐butyl‐3‐methyl‐imidazolium acetate demonstrate a synergistic catalytic effect on this new strategy. 1‐Butyl‐3‐methyl‐imidazolium bromide is essential in two parallel reactions owing to the good nucleophilicity and leaving ability of bromide, and 1‐butyl‐3‐methyl‐imidazolium acetate plays a dominant role in the subsequent cascade reaction owing to the strong basicity of acetate. In addition, the binary ionic liquids can be used thrice without significant loss of catalytic activity.

Transformation of Carbon Dioxide into Oxazolidinones and Cyclic Carbonates Catalyzed by Rare‐Earth‐Metal Phenolates

“…Gao et al. reported a three‐component synthesis of oxazolidinones from CO 2 , ethylene oxide, and amines catalyzed by binary ionic liquids (Scheme ) . This method, however, requires high CO 2 pressures (25 bar; 1 bar=0.1 MPa) and high temperatures (140 °C).…”

“…The reactor was pressurized to 10 bar with CO 2 and heated at 95 °C for 9 h. Upon completion of the reaction, the mixture was cooled to room temperature, and the pure product was isolated by column chromatography (EtOAc/petroleum ether 1:30). The structure was confirmed by comparison with literature data …”

BmimOAc ionic liquid: A highly efficient catalyst for synthesis of 3-aryl-2-oxazolidinones by direct condensation of 2-(arylamino) alcohols with diethyl carbonate

“…It is clear that the C-2 proton of imidazolium ring shifted step by step upon addition of DEC due to its interaction with carbonyl group of DEC. Similar results were reported by us and others [24][25]41]. On the addition of 10 eq.…”

“…In the course of our studies on the utilization of ionic liquids as catalysts, we reported approaches for the synthesis of 3-aryl-2-oxazolidinones via reaction of cyclic carbonates with aromatic amines, and the straightforward conversion of CO 2 using ethylene oxide and aromatic amines in the presence of catalytic amount of ionic liquids [23][24][25][26]. Although these approaches are regarded as green, they still suffer from relative long reaction time, high reaction temperature or large amount of catalyst.…”

Green Catalytic Synthesis of Heterocyclic Structures Using Carbon Dioxide and Related Motifs

“…This catalyst proved to be highly efficient for the coupling reaction between aziridines and CO 2 under reasonable reaction conditions (100 °C, p(CO 2 ) = 80 bar) without the utilization of any additive or cosolvents making it a rather green process. ILbased systems have also been reported in this same context and proven to be attractive catalyst systems though relatively high reaction temperatures are generally warranted to achieve acceptable turnover rates [101,104,105]. This selective behavior was also noted for most of the other investigated substrates with regioselectivities in the range 86-99%.…”