(2-Carboxyethyl)triphenylphosphonium bromide (
1) is most commonly applied to Wittig reactions on carbonyl substrates. An additional and green application of the phosphonium salt is in the CO
2 fixation of epoxides to furnish cyclic carbonates. In the presence of catalytic amounts of
1 and heating under CO
2 atmosphere, epoxides react with CO
2 to afford cyclic carbonates in high yields. This reaction proceeds under metal- and solvent-free conditions and requires only 0.5 mol% of
1 as a catalyst. In this way,
1 is employed as a green catalyst for CO
2 fixation reactions.