[discodermolide]

I'd stick with ethyl acetate. I would also go back to the original Pd/C you used.
You can try with a few drops of formic acid, but you may have purification issues.
Really one of the best methods for the hydrolysis of phosphonate esters is to use LiOH and heat. You get the Li salt of the P acid. Dissolve it in ethanol then add phosphoric acid, lithium phosphate falls out of the solution and is easily filtered off.

[Babcock_Hall]

I am worried that the LiOH would remove the trichloromethanesulfonyl leaving group by attacking the methylene carbon.  I will try to set up a reaction in ethylacetate tomorrow and see what happens.