Wittig reaction in presence of carboxylic acids
This works because the acidic starting material is going to be deprotonated as there is excess bicarbonate present. Because of the adjacent carboxylate group, the pKa of the phosphonium species is going to be around 6-7  pKa Table here so within the range where bicarbonate can deprotonate it. The reaction is between the anion of the starting material and the anion of the phosponium species in aqueous phase. This will only work for readily deprotonated phosphonium species and aqueous soluble aldehydes in the presence of excess base.