I neglected to explain a few things in my previous comment. The hydroxyl group was para with respect to the sulfonyl group in the paper I cited in my previous comment. We are attempting to synthesize a vinyl sulfone from 3-hydroxyisonicotinaldehyde. Although we were able to get a low but acceptable yield using an isomeric aldehyde in a Knoevenagel reaction, we have only obtained a few milligrams of the product with this aldehyde, which is not enough for our collaborators to use. That is why we are considering using a Horner Wadsworth Emmons reaction.