Efficient and Recyclable Cobalt(II)/Ionic Liquid Catalytic System for CO₂ Conversion to Prepare 2‐Oxazolinones at Atmospheric Pressure

Abstract

Summary of main observation and conclusion Converting CO2 into value‐added chemicals represents a promising way to alleviate the CO2 derived environmental issues, for which the development of catalysts with high efficiency and recyclability is very desirable. Herein, the catalytic system by combining cobalt source and ionic liquid (IL) has been developed as the efficacious and recyclable catalyst for the carboxylative cyclization of propargylic amine and CO2 to prepare 2‐oxazolinones. In this protocol, various propargylic amines were successfully transformed into the corresponding 2‐oxazolinones with CoBr2 and diethylimidazolium acetate ([EEIM][OAc]) as the catalyst under atmospheric CO2 pressure. It is worth noting that the turnover number (TON) of this transformation can be up to 1740, presumably being attributed to the cooperative effect of the cobalt and IL. Furthermore, the existence of IL enables the catalytic system to be easily recycled to 10 times without losing its activity.

Recent Advances in the Synthesis of Five-Membered Cyclic Carbonates and Carbamates from Allylic or Propargylic Substrates and CO2

“…A recent work of He et al demonstrates the conversion of various propargylic amines into 2-oxazolidin-2-ones 137 by using a CoBr 2 /ionic liquid 138 as the catalytic system (Scheme 35) [68]. As shown, N-benzyl terminal propargyl amines were reacted with CO 2 and gave desired Z-products in good to excellent yields (51-99%) under mild conditions.…”

“…The mild reaction conditions, low loading of the catalyst (5 mol%) and pressure of CO2 (1 atm) at 60 °C, and the lack of noble metals, as well as the easily available and inexpensive ligand, make this method attractive. A recent work of He et al demonstrates the conversion of various propargylic amines into 2-oxazolidin-2-ones 137 by using a CoBr2/ionic liquid 138 as the catalytic system (Scheme 35) [68]. As shown, N-benzyl terminal propargyl amines were reacted with CO2 and gave desired Z-products in good to excellent yields (51-99%) under mild conditions.…”

Recent Advances on Metal‐Organic Frameworks in the Conversion of Carbon Dioxide

“…Relative to CCS technologies, the strategy of converting CO 2 into high value‐added chemicals is a more economical method to reduce the CO 2 emission, which has been considered as a more sustainable way and conforms to the concept of green development. [ 6 ] Up to now, sorts of heterogeneous catalysts were employed to convert CO 2 into high value chemicals including metal oxide, [ 7 ] molecular sieve, [ 8 ] silica‐supported metal salt, [ 9 ] and porous polymer, [ 10 ] etc . Among these catalysts, metal‐organic frameworks (MOFs) with potential applications in the areas of drug delivery, [ 11‐12 ] proton conductivity, [ 13‐14 ] catalysis, [ 15‐19 ] adsorption and separation, [ 20‐25 ] have been considered as one of the most promising materials for the application of CO 2 conversion.…”

Chemodivergent Synthesis of Oxazolidin-2-ones via Cu-Catalyzed Carboxyl Transfer Annulation of Propiolic Acids with Amines

“…If the liberated CO 2 can be reused as a carboxyl synthon for further transformation, it will make the process sustainable and environmentally friendly. In recent years, a range of carboxylic acids and their derivatives has been employed in this carboxyl transfer reaction through a domino decarboxylative coupling/CO 2 -fixation procedure . In particular, the carboxyl transfer of propargylic or allylic carbonates has been regarded as a powerful CO 2 elimination–fixation strategy to construct carbonyl-containing heterocycles (Scheme a) .…”