I am attempting to convert an aldehyde into a vinylsulfone using Horner-Wadsworth-Emmons chemistry with lithium hexamethyldisilazane as the base (28.7%). The number in parentheses is the yield of a closely related, purified product, as reported in the paper I am following. With respect to the HWE reaction, the protocol specified stirring for an hour at 0 °C followed by two hours at room temperature. The other reactant is a diethyl β-sulfonylphosphonate.
Although the important thing is just to get the product, I am somewhat concerned about the low yield in the HWE reaction, given that this is a multistep synthesis. The only idea that I can think of as a possible improvement is to monitor the HWE reaction by TLC or by P-31 NMR (there should be a difference in chemical shifts of roughly 10 ppm). I have previously found P-31 NMR to be useful in that it is relatively sensitive yet ideally there are only two molecules present, reactant and product. However, I do not presently know whether or not incompleteness of the reaction was the reason for the relatively low yield in the step. I have not yet surveyed other similar reactions for yield, although I have seen a variety of bases used.